DIY Spray Foam Insulation – Things to Know Before You Spray

by on September 23, 2012Karie Fay

You need your money more than the electrical utility company does. That’s the point of having a well-insulated house: It keeps you comfortable, no matter what the weather or season, while saving more of your heating and cooling dollars. Spray foam insulation does the job better than other choices.

diy spray foam insulationLong ago, houses were poorly insulated (if at all) – first with sawdust and later with vermiculite – little absorbent pebbles that resembled kitty litter and sometimes, when it got wet, acted like it as well. Modern building technology delivered cellulose, Styrofoam and fiberglass batts. Reliable performers, each has a place in certain applications. But the newcomer on the block, spray foam insulation, has better insulating power, resists mold and insects, and also works in areas where other insulation doesn’t.

Spray foam insulation is divided into two major formulas, each with specific benefits and features that make it ideal in various locations. There are also three main application methods. Spray foam insulation comes in one-part formulas sold in small aerosol cans, two-component kits applied with a special low-pressure sprayer, and two-part kits designed for use with high-pressure sprayers. Understanding the different types, where they are used, and which are practical for the typical do-it-yourselfer to install is as critical to a successful installation as knowing how to properly spray it.

Open-Cell vs. Closed Cell Spray Foam Insulation

Each spray foam insulation product, no matter how it is applied, falls into either the open-cell or closed-cell category. Spray foam insulation in an aerosol can is typically closed-cell, but both low-pressure and high-pressure sprayers apply both types interchangeably.

So what’s the difference? Sure, both look much the same, insulate well and eliminate the need for a separate vapor barrier. Mainly, closed-cell is more rigid, exceptionally dense and offers a higher R-value, at 6.6, than open-cell spray foam insulation does at 3.9. Incidentally, open-cell is comparable to other insulation products while closed-cell insulates about twice as well. This means it takes twice as much open-cell insulation to achieve the same R-value as the closed-cell.

Closed-cell expands a little more slowly and creates a better moisture and air barrier than open-cell. Open-cell, in contrast, expands and cures quickly, causing the tiny cells to expand so fast that they break and fill with air, resulting in a soft, slightly spongy insulation that is more moisture-permeable than closed-cell.

Location is Everything

A slow-curing formula of open-cell spray foam insulation is favored in retrofitting wall insulation. Installers make small holes in the drywall and insert a sprayer nozzle, filling the cavity with a liquid that expands, like hair mousse or shaving cream, inside the wall. Using other formulas may cause your wall to bulge under the pressure and even burst.

In new construction, open-cell is often chosen for ceilings, interior walls – it soundproofs twice as well as closed-cell – and most anywhere you would use cellulose or fiberglass. Closed-cell should be used wherever moisture will be a problem, but either closed-cell or open-cell can be used in other, drier applications.

Spray Foam Equipment: Professional vs. DIY Installation

High-pressure sprayers attached to large drums of two-part foam formulas cover a lot of area quickly and are useful for larger jobs such as roofs or major renovations. Professional applicators bring a spray rig on a commercial truck to the house. Long hoses are threaded around and into the house where the installers, wearing protective gear, spray the insulation. This is not a DIY job. Not only is the equipment expensive, but specialized training is required.

Smaller projects, such as crawl spaces and attics, are suitable for low-pressure sprayers. With the proper protective wear, which includes eye protection and a respirator along with long pants and sleeves, an ambitious do-it-yourselfer can wield a low-pressure sprayer hooked to portable tanks of two-part foam insulation formulas. This generally isn’t something you can rent; disposable and refillable tanks are sold as part of a spray foam insulation kit, but the cost is steep. In addition, using the sprayer successfully can prove tricky. Most experts recommend leaving low-pressure sprayers to the professionals as well, so proceed with a DIY installation only after thoroughly reading the instructions enclosed in the kit. Each manufacturer will vary slightly in sprayer operation and other specifications.

So how can a frustrated but determined DIYer spray a little foam in his or her house? Try any general department store or home improvement center and look for a can of spray foam. Looking much like a bottle of canned air or lubricant, the one-part closed-cell spray foam has an attached nozzle that makes pointing, inserting and spraying easy. Designed to fill smaller cracks, gaps and holes around the house, the biggest drawback is a can won’t go very far. It’s the perfect supplement for a house that’s already insulated but has a little gap that was missed.

Preparing for Spray Foam Insulation

Whether you are spraying a low-pressure foam insulation or using spray foam in a can, make a plan of action before beginning. Examine the house envelope – the skin of the house, if you will, where heat meets cold – and identify areas where you see daylight, feel a draft, or find an obvious lack of insulation. Make a list so you know exactly where to go step-by-step, as the foam can very quickly clog the nozzle of a sprayer or can.

Clean debris from surfaces and sink or remove nails you encounter. Unlike painting or staining, detailed cleaning isn’t necessary, but it’s smart to remove or eliminate anything that will keep the insulation from bonding completely.

Before beginning, cover floors or nearby furniture and other items with plastic sheeting to protect them from excess spray. Cut scraps of plastic and tape in place over electrical outlets and light switches to prevent foam from invading the receptacle. Turn off any sources of flame near the installation area, as the foam is extremely flammable during installation. Open a window or turn on a fan to provide ventilation while you work, and have children and pets leave the area.

DIY: Spray Foam in a Can

Shake the can for about a minute to thoroughly mix the contents. Assemble the bottle, attaching the straw applicator or nozzle to the can top. Working quickly, stick the applicator into a gap or hole and squirt to fill about halfway. The foam insulation will swell instantly. Move on to the next spot, adding more foam to previous areas, if they need it, only after waiting 10 to 15 minutes or until the first layer is dry. Spray a little water over top before adding more insulation.

If the hole is overfilled, feel free to trim away the excess with a utility knife or other tool. This allows you to hang sheathing, trim, or any material you desire without a bulging surface underneath. Cure the foam insulation overnight before altering. It will shave easier when hard.

As with any method of application, take care to avoid overfilling holes excessively, especially around items such as windows and doors. Overzealous and inexperienced applicators may damage window and door frames or even break things if too much insulation exerts excess pressure.

Where to Apply Canned Spray Foam Insulation

As tedious and expensive as it would be, you could insulate with a can of spray foam insulation anywhere you would use a sprayer. However, due to the small amount in each can, it wouldn’t be practical. Some areas, in particular, are prime candidates for your attention with canned foam:

  • Seal gaps around windows and doors. Pull trim off to access space around the jambs that the builder may not have insulated properly. Take care to avoid overfilling these areas.
  • Add foam around wire and pipe entry spots, vents, or other intrusions through the exterior walls. Spray foam does not harm wiring.
  • Insulate around plumbing in the bathroom and kitchen.
  • Squirt insulation around dryer vents, working from either inside or outside the house.
  • Inspect the sill plate in the basement. Where the wood framing meets a foundation there may be a gap. Fill areas such as these with insulation.
  • Seal around penetrations from the attic to the ceiling, such as around registers and HVAC vents.
  • Run a bead around the attic trap door and along the eaves in the attic.
  • Add insulation where the siding meets the foundation on the house exterior. Leaving exposed foam on the exterior doesn’t harm anything.
  • Surround any electrical, water, gas or HVAC inlets and outlets. Even the smallest hole allows insects, pests and moisture or air entry to your home.
  • Insulate around outdoor faucets and exhaust fan outlets.

Hardcore DIY: Spray Foam With Low-Pressure Sprayers

If you’re taking a leap of faith and attempting a low-pressure installation on your own, assemble the sprayers as directed. From a distance of about 2 feet away, aim the sprayer nozzle at the wall and spray in an even sweep across the surface. Practice a few times to get the feel; spraying foam insulation is like spray painting a car or other item. You need a light, steady fan of insulation applied with a swing of your arm.

Use a back-and-forth technique to spread a thin but even coat of less than an inch in depth. Continue down the wall, ceiling or other surface, steadily applying more in a zigzag pattern. In fact, any time you stop for longer than 30 seconds, you must change the sprayer nozzle or risk clogging the machine – which may force you to purchase another one.

After two or three minutes, the foam will have reached full inflation depth of about an inch. Remembering your R-values – 3.9 for open-cell and 6.6 for closed cell – add another sweep to increase your R-values and energy efficiency. Each inch in depth will deliver the R-value stated, so multiple layers offer doubled or tripled values.

Avoid spraying a thick layer in one sweep to prevent it simply falling off the surface. For best results, check the temperature of both the ingredients and the environment before spraying foam insulation. Apply when temperatures range between 60 and 80 degrees Fahrenheit.

Aftercare for Spray Foam Insulation

Don’t simply paint over foam and treat it as a finished surface inside your home. Like any foam insulation, expanding foam ignites quickly and easily and the fumes it emits are toxic. Building code generally insists that interior applications are covered with a fire-resistant sheathing. Drywall works exceptionally well, as it resists burning for about 15 minutes. In addition, do not spray it with chemicals such as gasoline or expose it to extremely high temperatures or heat sources to prevent chemical reactions or combustion. Consult your local building code for further information about building safety requirements in your area.

{ 131 comments… read them below or add one }

Haywood August 26, 2014 at 3:27 am

Does installation spray foam in a can eat away at seals on pipes? I have a friend who said that I may have caused damaged to the pipeline. I did not directly spray the pipe, but I put a piece of cardboard up to fill a hole where the pipe comes from the ceiling and sprayed enough just to cover the cardboard from the bottom.

Reply

Bill Miller August 14, 2014 at 5:19 am

I have been researching this and am really grateful for your information. I have a house that needs to be insulated. Anyway thanks for helpful tips!

Reply

AUBREY ROGERS August 4, 2014 at 6:12 pm

WHERE THE METAL FLOOR VENT MEETS THE INSULATED AIR DUCT IN MY CRAWL SPACE CONDENSATION IS FORMING ON THE METAL PART CAUSING THE FIBERGLASS INSULATION AND SUB FLOOR TO BECOME WET I HAVE 12 AIR VENTS IN MY HOUSE. CAN I SPRAY FOAM AROUND THE METAL VENT FOR INSULATION AND A VAPOR BARRIER? CAN GREAT STUFF BE USED FOR THIS ARE WHAT DO YOU RECOMMEND?THIS WILL BE A DIY JOB.THANKS IN ADVANCE.

Reply

Kathy July 19, 2014 at 2:39 pm

I live in a bi-level house. Years ago I renovated my bathroom walls as water had leaked thru the tiles. I removed all wallboard, insulation and had some black mould. I cleaned and then used Kliz to seal concrete walls. Reinsulated, applied waterproof wall board and went to marble slab walls and soaker tub. There is a bedroom closet next to the bathroom so I opened up the walls in the closet and checked to see if moisture went that far. It never did and I basically left the walls open for years. Basically with the concrete exposed and no insulation needless to say I was losing heat. This year I used fiberglass insulation and wallboard and closed in the closet leaving an opening that I needed to be able to have access to my cleanout pipe that was running down fro the kitchen above. I noticed that the insulation was acting like a wick and was wet so water must be seeping thru the foundation walls. Also I had broken the plastic vapour barrier, wet side, years ago when opening the closet and had laid the insulation directly on the concrete walls and then applied another plastic vapour barrier on the warm side. So hopefully its only condensation. I have taken out the insulation and used a fan to dry the area and it does not seem to have any leaks just damp like a basement. My foundation sits above ground as I do not have a basement. I was wondering if I could use Great Stuff along the bottom of foundation and use rigid insulation board against the concrete wall and then apply the fiberglass insulation back and just leave space at the bottom for air circulation. Suggestions???

Reply

Daryl June 28, 2014 at 10:56 am

I just used “Great Stuff” foam spray to fill gaps in a new door installation. I hadn’t
Secured the nozzle completely….to shorten my narrative; I made the mistake of rinsing the clumps of wet foam from my hands in my kitchen sink before realizing
my potential error. Should I now expect my drains to clog up? Is there something I can do to minimize the damage?

Reply

dora June 9, 2014 at 4:17 pm

I have a issue with my interior walls that are connected to my neighbors I can hear everything that they do, and talk about. I am conciderng spray foam from the cans, drill holes to inject foam, to help with the noise. Any reason why this wouldnt be a big problem? If so ,suggestions for me which doesn’t require to remove the drywall?

Reply

Lee June 18, 2014 at 9:33 am

Canned spray foam can not fill a large void. You would use a dozen cans (likely many more) to fill the void between 2 studs. Also, you will not know if the foam was filling the gap. Canned foam does not expand very far, and tends to fall in clumps if you are not squeezing in to a tight crack.

Reply

vicad vte June 7, 2014 at 9:22 pm

My 6″x 6″wood posts (arbor) have decay where attached to concrete.Decay is about 5″ hole . Any problem if I fill the hole with foam? (I will have soaked the wood with
Copper green (brown) to stop fungi before using foam.)

Reply

Adam June 6, 2014 at 7:24 pm

How well does the spray foam hold up in hot climate weather? I live in the Dallas, TX area where we get several weeks to months of +100 degree weather, I have used spray foam to seal pipe cut-outs and after a couple years, the foam starts to deteriorate fairly quickly.
Thanks in advance
Adam

Reply

Lance May 26, 2014 at 1:04 pm

Thanks for the article. Question: I’m thinking of using this foam to stay inside my topless jeep, around my amp (bolted to the floor), to keep the rain off. Thinking of staying the foam around the amp, and then putting plexiglass on top. This may be outside your expertise, but some Qs I have:
1) will the foam seal to metal (jeep floor)
2) what’s the best way to secure plexiglass in top? Guessing I can’t drill into the foam. Will plexiglass “cure” into semi-wet foam?
3) any danger of amp overheating if foam is an insulator?
4) any potential fire danger if amp heats up and ignites foam?

Understand this might be a little beyond your expertise. But having worked with the foam, hoping you can provide some guidance as I look to think “outside the box”. Thanks for any advice you can provide!! -Lance

Reply

Karl May 27, 2014 at 8:36 pm

If you insulate the fan or radiator fins on an amp, it will certainly fail withing minutes.

Reply

Richard Abbott May 10, 2014 at 6:51 pm

I’m building new house and had spray foam insulation sprayed in. The soffit vent holes are clogged with foam. Is this a problem or was it done intentionally? How do I get the the holes unclogged?

Reply

Azawisza May 28, 2014 at 11:12 pm

Baffles should have been installed before they sprayed. The foam in the vents should be removed

Reply

Rodney April 28, 2014 at 6:43 pm

I am fixing to build a metal building and i want to insulate between the perlins.Will the spray foam work for this?

Reply

Reginald April 24, 2014 at 11:26 am

Where can I buy open cell spray foam in a can? I want to spray it in a finished wall where expanding pipes make a knocking sound. I want to use the open cell because it is softer and I am not trying to block water or air.

Reply

Ben2014 April 22, 2014 at 3:29 pm

I have just demo’d the entire 2nd floor of our old 100+ far old home. Every bit of insulation has been removed. I am considering spray foam insulation – contractor – and need a few questions answered:

1. In the areas where we will be “cathedraling” the ceiling, can we go to a complete seal or should a proper vent be added?

2. we are having the roof re-done as well, and will be doing it BEFORE the spray insulation to prevent any nail holes or new permeations. should we plane for a ridge vent or no vent?

3. if we go with a complete sealed roof, should we invest in a whole home ventilation unit? and if so, where should we place this vent to provide for the best movement and circulation of bad/good air?

4. how much space should I allow for the roof joists to clear the decking (underside)? should i use existing 2×4, 2×6, or 2×8 joists? (roof is pitched at 3/12 and we live in a snowy area of upstate NY… my fear being that added insulation will create larger amounts of snow load )

thanks for any and all info and answers to the above

B

Reply

Yaz March 9, 2014 at 9:06 am

Great article . Is it ok to use great stuff gaps and cracks ( not the fire rated one ) for heating ducts gaps and bathroom vent fan and electric holes ? Thank you .

Reply

Karie Fay March 16, 2014 at 12:10 am

Hi Yaz,

Thanks for the question. I found Dow’s Great Stuff Air-Seal Audit Checklist online and read up a little on the stuff. According to them, all of their formulas are combustible. However, each formula is meant for a different purpose. The Great Stuff Fireblock is what you would want to use around electrical wires and plumbing, from what I see, to meet building code requirements. Check the back of each can or the website for further guidance.

Hope that helps,
Karie Fay

Reply

Linda Margolin March 6, 2014 at 3:02 pm

I have exposed laths in my plaster wall where I sampled [aggressively] for asbestos, and knocked out the plaster between the laths. The laths are in good shape (in my 100-year home) but are missing the interstitial plaster. Can I simply spray foam over the laths before i patch the hole?
The lack of internal plaster may be more extensive than this solitary hole. Does it matter if only a small area is foamed? I don’t want to weaken the rest of the scaffolding when I reinforce the exposed lath.
By comparison, the laths in the basement ceiling are in dismal shape. The plaster ceiling is falling apart, so the previous owner covered some of the gaps with drywall, which is in various stages of disrepair. Can I just aim the foam can into the void and fill up the spaces? There are some areas that leak due to plumbing issues. Is it OK if the foam is sprayed into an area that may get wet?
Thanks for your help.

Reply

Karie Fay March 8, 2014 at 2:13 am

Hi Linda,

I am not quite certain what you describe about spraying foam over the laths and patching the holes. However, I think what you want is an expanding foam adhesive — This Old House has a video episode entitled, “How to Repair Plaster Walls” that I think you will find extremely helpful.

I would hesitate using expanding foam behind your plaster since it exerts pressure as it expands. In your basement ceiling, you mention water leaks as well. Please don’t seal off a water leak. You really need to fix the leak, air out the area, then repair. Since you have patches of drywall already, I might be tempted to simply drywall the entire thing.

Sorry I couldn’t be of more help,
Karie Fay

Reply

KRIS G February 26, 2014 at 8:27 pm

i have live in the NW chicago land- on the lake.
my house is on a crawl about 22″ of mud floor– it gets 25 deg under there when it drops below 0 – it Does flood every year– usually it doesn’t hit the first floor but it gets within 1 inch of it– and in the future MAY reach it to flood the entire 1st floor.
with that said is t a good/bad idea to use closed cell on wood that may/probably see some water each year?- or is it just better to spray the foundation walls with the closed cell- but what about the Ciel plate made of wood- will that rot if i use the closed cell and it gets soaked -will it dry out?
will my floor boards dry out if I use the closed cell? or open cell?

Reply

Karie Fay March 8, 2014 at 2:17 am

Kris,

Ouch – that’s a bad situation. Expanding foam insulation will block moisture — but I would want a vapor barrier up at the very least wherever you don’t have expanding foam insulation. You can spray the foundation walls and make sure to enclose the sill plate too. However, the flooding concerns me. All that moisture may already be causing problems. I would suggest inspecting the area closely and asking a local contractor or building authority how they usually handle it. While foam blocks moisture from wood, I would hate to see another problem develop.

Good luck!
Karie Fay

Reply

Richard March 8, 2014 at 3:02 pm

Kris, I’ve done a lot of research on this and I am in the process of insulating mine as we type. First thing is stop the water. PERIOD. not only is it a moisture issue but also a foundation issue. After that apply 6 mil plastic sheeting over the dirt floor. I’m Assuming its dirt? Make sure to run it up the block walls also and any columns you may have. Then you can use CLOSED cell foam in betwwen your floor joists to seal any remaining air or moisture and also increase your r value. All the water you have, I would be very concerned with mold also.

Reply

emily February 17, 2014 at 12:04 am

Is it OK to spray foam behind a electric stove? Worried about a possible fire. Its also near the cord cause we have a wire there n mice are getting in. Is it OK to use it or is it a fire hazard??

Reply

Karie Fay February 23, 2014 at 12:47 am

Hi Emily,

First, spray foam insulation won’t stop the mice. They can — and may — chew through it if they are determined. You can block them better with some steel wool stuffed into any cracks or holes. Of course, that still doesn’t serve you for insulation. As far as using spray foam near a source of high heat like your stove, I would be leery of doing so. It starts to degrade at temperatures of around 240 degrees F, from what I see. That said, you could put a fire-rated material, such as a piece of drywall, over it. If it’s behind your stove, no one would see anyway.

Hope that helps!
Karie Fay

Reply

Debbie February 16, 2014 at 4:42 pm

I was told that if I sprayed foam underneath the floor boards of my home that there would be a build up of moisture between the foam and the wood and cause rot. Is that true? Would you recommend contacting a professional to do the work?

Reply

Karie Fay February 23, 2014 at 12:54 am

Hi Debbie,

I am curious who told you that? I did a little research, and it confirmed what I suspected. It should work well. Feel free to ask an expert for a second opinion. However, spraying the foam insulation under your floor boards creates a vapor barrier that not only seals out air and thermal transfer (heat and cold) but keeps out insects and spiders too. Most of the moisture would arise from the soil, underneath your home, and the insulation will block it from absorbing into subfloors or wood floors above. Fiberglass is more of a problem than spray foam. As fiberglass ages it sags, allowing a dead air space where moisture can penetrate and accumulate. You won’t have this problem with spray foam.

Hope this helps!
Karie Fay

Reply

Dick February 7, 2014 at 3:43 pm

Karie Fay, I’m inclined to disagree with your comment that products like Great Stuff are not cost effective for large jobs. Great Stuff comes in 16 oz cans (1 pound). If, as you say, it is closed cell foam the cured foam should have a density of 2 pounds per cubic foot and a can should produce about 1/2 cubic foot of foam per pound. This would be about 6 board feet per can. Each can costs $4 in my Home Depot and Lowes. Thus it costs $0.66 per BF. The best price that I have seen on the Internet for low pressure polyurethane DIY foam kits is $600 for a 600 BF kit, $1.00 per BF. Thus these large kits cost at least 50% more than the Great Stuff. Of course I calculate that I would need 200 cans for my attic! Also you do get some additional safety equipment with the kits. For the DIY, the 200 cans of Great stuff may actually be a lot easier to deal with than one of those kits. If my logic wrong? And are you certain that Great Stuff is a CLOSED CELL foam?

Reply

Connie April 9, 2014 at 1:54 pm

Dick, you really have me thinking. Is Great Stuff the same as the other closed cell foam insulation? I was looking to do it myself and I agree the small cans would take a lot of cans but would also be easier to handle. Will it really work as give as much insulation as the stuff the pro’s use? I live in Las Vegas, so we have hot hot summers. I did check and great stuff is closed cell foam. You seem pretty smart, what have you found out?

Reply

Connie April 11, 2014 at 2:00 pm

Kerie Fay, what do you think about my question?

Reply

Karie Fay April 15, 2014 at 10:09 pm

Hi Connie,

How big of an area do you want to insulate? Who will do the installation?

I don’t agree with Dick, actually. Here’s my take on it:

There are several products comparable to Great Stuff. Some may be more expensive or cover more area, etc. Still, for a comparison’s sake, lets stick with Great Stuff.

What does Great Stuff say about coverage? Their “Big Gap” formula says that a 12 oz. can = up to 19 tubes of caulk, a 16 oz. can = up to 24 tubes of caulk and a 20 oz. can = up to 30 tubes of caulk.

Now, a tube of caulk doesn’t go very far. In feet, those cans would equal 250 lineal feet (12 oz), 335 lineal feet (16 oz) and 420 lineal feet (20 oz). That’s based on a approximately 1/2-inch caulk bead size.

Using the formula for a volume of a column, as this bead is now 420 feet long and 1/2 inch in diameter, we can calculate the coverage better. Take pi * radius squared * height OR 3.1415*0.0625*5040=989.58 cubic inches. One cubic foot is 1728 cubic inches, so one 20 oz can of Great Stuff yields approximately .5 cubic feet of coverage.

There’s about 12 board feet (a square foot with 1 inch depth) in a cubic foot. So, half a cubic foot = 6 board feet.

How much is Great Stuff in your area? Using my calculations, you would need AT LEAST 100 cans to cover 600 square feet. At a cost of, let’s say $5 a can, that’s $500.

I find the kits all over the internet for $500 – $600 as of 2014. Of course you can pay more, but for the sake of comparison, we see it’s comparable.

What isn’t being mentioned is a couple of things. First, you will be hard pressed to get all the foam out of the can. That coverage is based on optimal conditions — the right temperature, application methods, nothing coming out in a glob or the nozzle getting clogged… I would think a few extra cans isn’t out of the question no matter who applies it.

Also, you won’t get the density he mentions. That density is achieved with the kits, which are two-part formulas, whereas Great Stuff isn’t.

Each product has its place. No doubt. But when it comes to the best results, go with the kit if you can. It will be less hassle in the end and simply insulate better.

That’s my take on it.

Hope that helps!
Karie Fay

Reply

Connie April 17, 2014 at 11:13 am

OMG, this is really such a big deal, I just want to get it right. We are enclosing a carport into living space. Here was another suggestion, see what you think. How about this product from home depot?

http://www.homedepot.com/p/Unbranded-Thermasheath-3-2-in-x-4-ft-x-8-ft-R-13-1-Polyiso-Rigid-Foam-Insulation-Board-613010/100573703?N=5yc1vZbaxx

They describe it as “R-Matte Plus-3/Thermasheath-3 is rigid foam plastic thermal insulation board composed of environmentally sound, closed cell, polyisocyanurate foam bonded to a durable white-matte (non-glare) aluminum facer and a reflective reinforced aluminum facer. This product is suitable for use in wall sheathing applications in new residential, commercial and agricultural buildings and for thermal retrofit construction to existing buildings. This Energy Star qualified Rmatte Plus-3/Thermasheath-3 provides R13.1 with dimensions of 2 in. x 4 ft. x 8 ft. This product is designed for exterior and interior, non-structural uses.

Rmax Polyiso sheathing offers the GREATEST R-value per inch currently available in a rigid foam board.
R-Matte plus-3/Thermasheath-3 is applied to the exterior or interior face of wood or metal studs to cover all studs, sills, plates and header constructions, thereby providing insulation over areas not normally covered by insulation products
Superior resistance to moisture and vapor in above grade applications.
Polyiso ridgid foam board offers superior fire protection properties compared to any other ridgid foam board insulation.
Energy Star qualified to meet or exceed federal guidelines for energy efficiency for year-round energy and money savings.
When taped and flashed, the Rmax Polyiso board greatly reduces air infiltration and prevents thermal bridging caused by heat and cold tranmission through studs.
Lightweight and easily cut to size”

What would you think of using this between the studs. The walls are 8 ft by 19 feet and 8 feet by 25 feet.

Do you think the spray kits are still better or would this be just as good? It is important we have the best insulation we can get.

Karie Fay April 24, 2014 at 5:11 pm

Hi again,

I have a much better idea what you want to do, now. Here’s my thoughts.
You could use spray foam insulation, but personally, I don’t think the hassle or expense is worth it. I understand you are anxious to do the best possible job. However, that’s more about installing the proper R-value than using the “right” insulation.

The rigid foam insulation you refer to in your link seems like an excellent product. With a 2-inch-thick sheet you can count on about an r-value of 13. You will also pay a LOT less than using spray foam. Using 4×8 sheets, you will need approx. 22 sheets (provides a little extra). At approx. $20 a sheet (per the Home Depot link) this will run you about $400. That’s less than the cost of spray foam at an inch of depth, not to mention a 2-inch depth.

Another alternative is fiberglass batt insulation between the studs with one layer of rigid foam insulation over top of it, nailed to the studs to secure. Personally, I probably would do that. Either way, tape the seams where the foam meets to ensure you have no moisture or vapor leaks.

If I can help further in any way, Please let me know.

Karie Fay

Connie April 25, 2014 at 2:26 pm

Karie Fay, first of all I can’t thank you enough for all your knowledge and wisdom. For someone like me who does not have a clue and just trying to do the best I can, I really appreciate it more than you can imagine. You have been a life line! So we should go with the fiberglass first, then cut the foam so it meets in the middle of the stud(?) and some kind of tape over the seam. Duct tape? Or is there some kind of other tape, or do we cut the foam so it fits inside the stud? I promise this will be the last question.
Soooooooo, what do you think?

Kate February 6, 2014 at 11:48 am

Hi there,

Does spray foam that you can buy from a DIY store offer any sound insulation?

My situation is that I live on a busy main road, and I have an air vent in my bedroom above the window. The house is old, so the vent is essentially a foot deep hole in the wall covered by metal grates either side. Draughty yes, but regarding the noise level, I might as be outside with the traffic. Don’t even get me started bout the noise of the wind if it’s stormy. There is a more modern vent in the room, so I don’t really have any qualms about sealing the old one, just wondering what the best way to go about it is. The landlord has ignored every request I’ve made to address this problem, so I find myself having to deal with the problem with no DIY knowledge or skill.

Anything you have to offer me would be greatly appreciated!

Thanks

Reply

Kate February 6, 2014 at 11:53 am

I should also add that the metal grates are not removable, hence I’m struggling to think of a way to fill the void.

Reply

Karie Fay April 15, 2014 at 10:11 pm

Hi Kate,

Opinions may vary, but personally I would go for it. I assume no critters ever come through the vent? If they do, put some fine screen over it before spraying it down with spray foam insulation. Spray foam insulation will insulate and block a tremendous amount of sound. In fact, foam deadens sound much better than drywall or fiberglass.

Good luck!
Karie Fay

Reply

Jim miller January 31, 2014 at 6:03 pm

We are going to insulate the lower portion of the walls at my dad’s house. The upper potion is paneling and bat insulation was used. However, the lower potion is a customized knotty pine horizontal slat wall. There is about a 2″gap that is 4′ up the wall we will be insulating the wall through. I have 2 questions:

Is it feasible to blow the insulation in from the top to fill the cavity?

Will the foam expand and make the wall bulge damaging the wood?

Reply

Karie Fay February 1, 2014 at 11:16 pm

Hi Jim,

Were you wanting to do this yourself? If so, I would recommend consulting the product specifications to be completely sure. In most cases, holes are drilled into the walls at about 48 inches in height. I have never used the insulation in this way, but I understand that the foam should ooze out the holes if you overfill the wall cavity. So it shouldn’t get full enough to bow the walls out.

Hope this helps!
Karie Fay

Reply

Kelli January 26, 2014 at 12:25 am

Hi I have an old farm house and one of the rooms had a dirt floor, he put down a floor but my pipes for my washer is in there an with the extreme cold weather. We have had they are freezing. Can I crawl under there and use the can spray foam on the outside walls to stop the wind ? It not a big area prob about 5-6 feet of wall at a foot and half. Any suggestions would be so Greatly Appreciated. I’m an off work single parent and money is Very tight right now. Thanks again for ANY help kelli

Reply

Karie Fay February 1, 2014 at 11:05 pm

Hi Kelli,

If I understand correctly, there was a dirt floor and someone put a real floor in, but it is raised about 18 inches from the dirt? And the pipes run through that unheated area? If I have it right — ouch. Yes, I think if you can get in there, spray foam insulation would help immensely. You can also try rigid foam insulation. Cut it to the size needed and wedge in place along the wall. Then maybe squirt spray foam insulation over any gaps to seal the installation. The important thing is to make sure it’s completely covered so no air or moisture can pass through. Rigid foam insulation will save you money as well.

If you have any other questions feel free to ask!
Karie Fay

Reply

Carole January 24, 2014 at 4:06 pm

We are considering having foam spray installed in our attic of our existing home. Will the added weight cause cracks in our sheetrock?

Reply

Karie Fay February 1, 2014 at 11:00 pm

Hi Carole,

I don’t think you have anything to worry about. I did a little research, and according to the information I found, one solid cubic foot (1 foot high, one foot wide, one foot thick) weighs between about 1/2 lb./cu. ft. for open cell foam and at most about 2 lb./cu. ft.

Given that open cell has an R-value of about 3.5 per inch and closed cell delivers about 6 per inch, I doubt you will need a foot of insulation. So you aren’t putting as much weight on there as you may fear. You can find the exact weight by calculating the depth needed and how much a 4-by-8 sheet of drywall would therefore hold.

Hope that helps!
Karie Fay

Reply

TERRY B. January 11, 2014 at 1:23 pm

I HAVE A STEEL BUILDING CAN USE FORM INSUL. ON THE INSIDE

Reply

Karie Fay January 20, 2014 at 12:00 am

Hi Terry!

Oh yes! You not only CAN use the spray foam insulation inside a metal building, but many people prefer that method. Spray foam insulation provides a high R-value in comparison to the fiberglass batts or rigid foam insulation, and holds up much better to wear and tear than either, assuming you will leave your walls exposed on the interior. The best thing about using it, however, is no separate vapor barrier is needed. If you can afford to do it, I think it’s a great idea.

Thanks for the question!
Karie Fay

Reply

Ken January 27, 2014 at 7:06 pm

Karie Fay,
I have tried to use Great Stuff foam before on the sill plate of the basement to stop air flow. Right after spaying the foam fell off. The same thing happened when I tried to apply it in a bathroom reno to an exterior wall.
I have no Idea why. Any suggestions?
Thanks,
Ken

Reply

Brian January 28, 2014 at 3:01 pm

Did you spray water on first? seems to be a catalyst in some way.

Reply

Ken February 1, 2014 at 7:53 pm

Brian
No I did not, but I will.
Thank you very much for the help. I’ll let you know.
Semper Fi
Ken

Mereya January 9, 2014 at 9:03 am

I have a question… We just got our new kitchen installed and have our new sink location over an existing central air vent. The guy cut a hole out of the toe kick for the air to escape, but most of the air seems to be just circulating around in the space under there. When I asked the cabinet maker about how to make that more efficient, he said they could spray the foam under there to make a funnel type thing for the air, but I am worried about it getting too hot when the hot air is blowing out. Should I be worried?

Reply

Karie Fay January 19, 2014 at 11:55 pm

Hi Mereya,

If I understand correctly, a sink and cabinet was placed over a floor vent or perhaps against the wall vent. Since it’s still blowing air, a hole was cut in the bottom of the cabinet to allow hot and cold air to escape. Am I correct? And now the cabinet person wants to create a tube of foam to funnel the air out of the cabinet space into your room?

To me, that sounds like so much hassle. I question why the vent was left open. Here’s the deal: It’s not good to close off too many HVAC vents. It makes your system work more inefficiently, leading to wear and tear plus more energy consumption. BUT. You can safely close off a certain number of vents. One or two is likely okay. So the simple and logical way to approach your situation, it would seem to me, is to cap your vent and eliminate the problem.

Barring that, you probably could make a tube of insulation. It won’t get too hot from the air exiting your furnace — the air temperature isn’t that high. Even then, it seems to me there are simpler ways to route the air.

My suggestion? Board the vent up. Try asking them why that isn’t a solution (and keep in mind their specialty — it’s not HVAC).

Good Luck!
Karie Fay

Reply

Sebastian December 1, 2013 at 1:20 pm

Hello,

Great article! I have a two quick questions:

1. I am planning to do DYI foam spraying after removing inside part of drywall in my house. I would like to use closed cell formula and then cover it with new layer of drywall installed inside of the house. Outside side of the house is covered with vinyl siding. I am not sure if there is a rigid foam between siding and outside drywall (planning to check on this)… If there is one – would I run into risk of creating two layers of vapor barriers and trapping moisture between sprayed foam and rigid foam?

2. Also, my house is situated on the slab on grade. There is no insulation under the slab and removing the slab and adding insulation seems to be very expensive. If I insulate entire house well, but leave out the slab, would it be a huge drawback heavily affecting entire house R value?

I appreciate your help.

Reply

Karie Fay December 7, 2013 at 9:42 pm

Sebastian,

Hi, and thanks for the compliment. Regarding your questions, I would first advise talking to your building code inspector. I don’t know where you live, and vapor barrier issues can depend so much on your region. You are correct that you don’t want a double layer of vapor barriers, however — moisture must have somewhere to go.

As far as your slab — it’s concrete. Concrete absorbs heat. I would honestly recommend insulating under your floors if you can practically do so. Otherwise, do it as you can (if for instance you refinish a floor in a given room) and don’t worry about it. Balancing the savings from your R-value with the cost of insulating the slab it probably just isn’t worth it.

Hope that helps,
Karie Fay

Reply

Annie Bean December 1, 2013 at 6:02 am

Hi
My home is 150+ year old, but mostly rebuilt due to fire in 2000. Contractor installed batt insulation( that yellow fuzz stuff) along with rigid board in some places. Several rooms are just way too cold and you can feel drafts especially when windy. I’m in ny.
Can slow rise be used in existing walls which are already insulated?

Reply

Karie Fay December 7, 2013 at 9:31 pm

Hi Annie,

I wish I had more of an idea about your current situation. You say a contractor did the work, and that fiberglass and foam board insulation was installed in “some” places?

If your contractor did a proper job the R-value in your walls should be adequate. However, do you know if there is a vapor barrier? Was expanding foam insulation sprayed around window frames and electrical outlets and other gaps?

A lot of times you can find a local utility company willing to perform a home energy audit. This will tell you exactly where you are losing heat. Also, try checking out my articles for winterizing information and insulation information.

Hope this helps you stay warm -
Karie Fay

Reply

Jilly November 29, 2013 at 7:33 am

A quick question, more for research than practicality. Regarding expanding foam, I understand the external temperature range advised for efficient use, but I would like to know what kind of temperatures the foam itself can reach as it cures (like Plaster of Paris does), particularly in a confined space? Thanks. Jill.

Reply

Karie Fay December 7, 2013 at 9:37 pm

Hi Jill,

What a neat question! Unfortunately, I haven’t a clue. Of course there’s a chemical reaction that takes place as the foam expands, so I would expect a heat transfer of some sort. I wonder, however, if it isn’t dependent on the ambient temperature as well. I would suggest writing or emailing a manufacturer and asking. I would be curious to know the answer!

Good Luck!
Karie Fay

Reply

brian November 28, 2013 at 5:01 pm

Hi,
I want to spray a closed cell foam into the top row of my basement cinder block cores in an effort to mitigate radon. i’m wondering if the cessation of air flow would help with this AND what type of foam would be the most expandable so i could swish it around the opening and have it seal without having to fill too much depth? thanks.

Reply

Laura November 21, 2013 at 9:46 am

We just recently concreted our crawl space floor and spray-foam insulated the exterior walls in the crawl space (both were professionally done). I have two questions: (1) how long do we have to wait until we can start storing our stuff in the room (most items will be in plastic containers), and (2) do we need to cover the walls with the spray-foam insulation or can they remain exposed? We installed 4 lights in the crawl space so we can easily see in there, and I want to say I recall seeing something about UV rays deteriorating the spray foam over time. We spent all this money fixing up that room and I just want to make sure it stays in as great a shape as we can keep it. The company doing the work says it takes 28 days for the concrete to fully cure, but I really can’t wait that long to put everything in that room. Any advice or opinions is appreciated. Thanks!

Reply

Karie Fay November 25, 2013 at 9:00 pm

Hi Laura,

I hesitate when you ask how long before you can store items on freshly poured concrete. The contractor told you 28 days, and that is indeed when it should be fully cured — dried and hardened. Sometimes they tell you that you can drive on it much sooner (if it was outside) but keep in mind that’s a temporary weight. I have no idea how heavy your boxes are, or what condition the concrete is in. I would suggest trying to wait just as long as you can — you don’t want to mess it up, as you said, and weight could leave dents in the floor.

I am uncertain what you want to know about the spray foam insulation. What walls are you wanting to cover? From what I hear, it sounds like you’re already in good shape… if you can be more specific, I am glad to try and help. Oh, and lights won’t hurt your foam insulation. It’s the sun that deteriorates it.

Good luck!
Karie Fay

Reply

Kirk Leadbetter November 14, 2013 at 8:56 pm

Hi Karie,

Redoing a finished basement in a Late 60’s, below grade apartment. We’re removing all the batting and planning on a diy installation of closed cell foam for the exterior walls which is mostly concrete or plywood. My question is, what about between the ceiling in the basement and the floor above it? I’m hearing that you don’t want a vapor barrier between two heated spaces.

I’m looking for:

1. keeping the basement heat in the basement
2. soundproofing or sound deadening

Is foam the way to go or should I consider batting or open cell foam? There are lots of wires (no junction boxes) and pipes that I’d be spraying around.

Reply

Karie Fay November 25, 2013 at 10:19 pm

Hi Kirk,

I wouldn’t think it would be a problem per se to use spray foam underneath your floor (the ceiling of the lower level). You won’t have enough of a temperature difference between the two areas to form any real condensation, in my opinion.

That said, I am still hesitant about using spray foam. I love the stuff in certain uses — but if you ever need to get to any wires or pipes in it, that won’t be it. Have you thought about fiberglass topped with rigid foam? I would think that would be more economical and fairly good at stopping noise.

Hope that helps,
Karie Fay

Reply

tedone November 13, 2013 at 5:13 pm

I have a home with plaster walls that was built without any insulation in 1958.
I want to replace the exterior siding and sheathing soon.
My question is: When I remove the siding and sheathing, would it be okay to spray the backside of the plaster walls with spray insulation at that time? The plaster walls are in great condition and I dont want to fill from the inside. I havent heard of anybody doing this, and want to confirm that this wouldnt cause moisture with the air gap between the foam and new siding. Should I use open or closed cell?
Thanks, Ted

Reply

Karie Fay November 25, 2013 at 10:16 pm

Hi Ted,

From what I understand in listening to others discuss it, an air gap between the foam insulation and the siding would actually be beneficial, since it allows a slight air pocket that allows drying on the inside. In fact, others have sprayed foam behind plaster walls — though typically by drilling holes into the wall and filling the stud cavities. Still, I personally am hesitant about what you propose (and others may feel differently). As long as you have the walls opened up from the exterior, why not use fiberlass and rigid foam on the exterior, underneath the siding? Seems to me cheaper, easier and more conventional.
You could try asking a local contractor what they suggest. Practices vary from area to area, of course.

Good Luck!
Karie Fay

Reply

Indy November 6, 2013 at 2:00 pm

Hi I used expanda foam on an aluminum awning where my ex had enclosed the underneith of the awning to look nice but some how left a hole for squirrels to squeeze in. I did three awnings and now I am a nervous wreck that maybe the expand a foam could catch fire in the summer heat. These are on the second floor and I worked from the window. Now if it is wrong to do this I will need to hire someone to try and remove it. :( It kept the squirrel out. I trimmed as much as I could off but on the outside of the awnings where I couldn’t get to I couldn’t trim right. Sun would probably hit it. I know this might be hard to envision cause who covers the inside of awnings. Thanks for any help

Reply

Karie Fay November 10, 2013 at 1:58 am

Hi Indy,

Now that’s a new one to me. But don’t worry – I won’t tell anyone! :)

I can’t actually envision what you are talking about, but I think I can set your mind at ease. Expanding foam insulation is unlikely to catch fire or anything from exposure to the sun. It would take extremely high temperatures, like hundreds of degrees. NOT to say it’s ok to use in high-heat areas, mind, but the sunlight isn’t that great of a risk.

The bad thing about sunlight exposure is I would expect it to degrade eventually. Same with exposure to weather — rain, wind and such. You may want to consider a more permanent solution. Since I can’t look at it, I really can’t advise you without a mental vision of the situation. Still, you’re probably good for several years. And it keeps those darn squirrels out!

Good luck!
Karie Fay

Reply

deedee October 30, 2013 at 1:31 pm

My house designer has suggested applying closed cell insulation on the bare ground under my house. Are there any circumstances in which this could work, for example if a plastic barrier were placed on the ground first?

Deedee

Reply

Linda November 14, 2013 at 2:23 pm

Hi Deedee,
It’s great to hear you’re thinking of spraying closed cell foam under your home! Crawl spaces and basements are notorious for higher levels of moisture, which can lead to mold, so it’s critical to keep the dampness from rising up into the living area. Closed cell foam will provide you with a seamless air barrier, stop moisture penetration, and give you a very high R value; however, spraying directly to the bare earth may not provide you with the results you’re hoping for long-term because the earth may shift or settle and you’ll lose the tight seal. If the main goal is to prevent the cold and dampness from migrating up into the home, spraying closed cell foam to the underside of the floor above will yield tremendous results!
Linda

Reply

Scott October 26, 2013 at 4:27 am

I have taken up the original flooring in a 1925 house. Over the years the subfloor boards have separated from each other about a quarter of an inch. I was thinking of using spray foam in those cracks. I’m going to install a new hardwood floor on top of this subfloor, probably using a tarpaper underlayment. Woud this be a good idea? Thanks!

Reply

Karie Fay November 10, 2013 at 2:12 am

Hi Scott,

Good thinking, but I have a few questions first.

When you say the subfloor boards, are they like a wood floor with planks? What’s underneath the subfloor? Is there a crawl space, a basement, or a slab? Do you know what — if any — insulation is underneath the floor already?

The thing I am thinking is this. Sure, you can fill those cracks with spray foam. There’s almost no “wrong” answers to using spray foam insulation as long as you don’t expose it to extremely high temperatures.

However, you would have to make sure that you level the top so a new floor won’t have bumps and hills to deal with. Tarpaper, while a great leveler and underlayment, can only compensate so much.

If you can get to the underneath, I would rather see you insulate beneath the floor. You can use the same spray foam insulation that way, or use rigid foam insulation. Fiberglass batts are also a reasonably priced solution.

Consider your circumstances and the questions I asked. You seem to have good thinking – I think you will find the solution best for you.

Thanks for the question!
Karie Fay

Reply

Michael October 22, 2013 at 5:18 pm

Lapolla Foam Lok and sealer was sprayed on my 2007 Jeep. Won’t come off. Leaves white spots on paint. On hardtop Plastic it has pitted surface. Cannot paint Jeep hardtop. Must be replaced??? or any scientific info you can give to remove. I’m pretty upset. The spray company says its not that bad. What a bunch of dummies.

Reply

Becky October 9, 2013 at 9:26 pm

Hi – I live in NW Georgia, in a 59 y.o. house with in-slab air ducts. Have found mold in the “reachable” areas of the ducts. I’m guessing moisture has gotten into the ducts from ground water. Am going to abandon this duct system & go overhead.
Thought of filling the in-slab ducts with concrete or foam, but am wondering if it would be just as good, to stuff something down into the “ends” of the ducts, then add concrete as a plug.
Was going to have the mold removed, but what good would that do, if moisture IS getting into the duct system…it would just get in again & cause more mold. The best thing to do seems to be close off the system, so that no air from it can get into my house.
Any ideas on this?
Thanks!

Reply

Karie Fay October 21, 2013 at 2:11 am

Hi Becky,

My understanding is by and large, the in-slab duct systems have been mostly done away with due to problems such as yours. While I honestly hate the thought of leaving mold anywhere, the pros do indeed say you can plug it with concrete. Don’t fill it completely — that would get expensive. Instead, create a backing at the duct entrance, for instance filling it with some stiff, strong wire that will fit snugly. Then add concrete — the wire will reinforce it. You can cover your plug with drywall or something similar and you’ll never know it was there.
Out of curiosity, did you notice a smell? Your indoor air quality (IAQ) had to be poor with mold in the ducts. I would urge you to try to find out HOW you are getting the moisture as well, so it doesn’t just simply move elsewhere. How is your yard drainage? Are your downspouts in good repair and away from the house a little bit?

Hope that helps,
Karie Fay

Reply

Jim Barrows October 7, 2013 at 10:07 pm

Hello There: I have a 1994 Bellavista Modular home and live in colorado, i am looking at reinsulating, what type of insulation should i use, spray or the denim batt insulation. Any suggestions would be appreciaTED. Thanks Jim

Reply

Joe September 26, 2013 at 6:57 pm

I live in an apartment with central heating/cooling. The unit in our living room has a 3″ gap at the bottom…that lets in all types of creatures. Can I use spray foam (like GreatStuff) to fill that space? My concern is the heating. From what I can tell it wouldn’t directly touch any pipes or anything. Any guidance is appreciated! Thank you.

Reply

Karie Fay October 5, 2013 at 9:44 pm

Hi Joe,

I am not clear what gap you are describing. However, if you have a gap to the outside that bugs and animals can get through — yikes! Have you called it to your landlord’s attention?

Great Stuff and other canned foams you find at the hardware store contain closed foam. It cures to a more dense, rigid product. It insulates better and yes, it should keep those varmints out! As long as it isn’t touching anything of high heat, or near a source of high heat, you will be fine. My rule of thumb — if I can’t lay my hand flat on a hot surface, I don’t put anything flammable near it.

Hope this helps!
Karie Fay

Reply

Andrea September 23, 2013 at 6:40 am

Would this be a good option for an 80 year old house which has had various building phases. We have no idea what is in all of the walls. It has been divided into three apartments.

Reply

Chris September 13, 2013 at 10:58 am

Karie Fae,
I’ve got that out there in left field kind of question. I’m refitting a 52′ yacht; what are your thoughts on using closed cell to provide a good insulation for both hot and cold climate control? I’m sure I would have to hire a pro, even though I’m an avid DIYer; the cost of the DIY tanks seems to make it worth hiring a contractor.
Thanks,
Chris

Reply

Karie Fay October 5, 2013 at 9:34 pm

Hi Chris,

They actually advertise a marine-formula closed cell product. And you’re correct — the DIY tanks do run some money. I think it would work wonderfully, and depending on where on the boat you’re applying it, you may just be right about the professional installation. In small areas, foam in a can will often work as well.

Good Luck!
Karie Fay

Reply

Steve C September 11, 2013 at 2:05 pm

I have a somewhat different use that I’d like to know if it’s feasable to use spray foam insulation. At a trade show, I want to fill an open backed cavity of a plastic acoustic diffuser that is approximately 24″ x 24″ x 5″. And I have 16 of them and they will be hung on walls with the open (foamed) back to the wall. The cans at Home Depot seem to be designed for cracks & beads rather than filling voids. Does anyone sell open cell in cans? Any suggestions?

Many thanks

Reply

Karie Fay October 5, 2013 at 9:31 pm

Hi Steve,

The reason the canned foam products say they are for cracks and voids is because it is very expensive to fill a large area with it. An entire wall would take several cans and it wouldn’t turn out as precisely as if it was applied with a sprayer.

Closed cell (the type in cans) is also more expensive than open cell and insulates better as it’s more rigid.

What you really want is open cell. You can find DIY kits — the trick will be finding one you can afford. You don’t need hundreds of board feet, I assume. So a small kit is perfect.

Another option is taking it to a spray foam installer and find out if they would fill your diffusers for less than a kit would cost. They just might.

Hope that helps,
Karie Fay

Reply

Reinhart September 1, 2013 at 9:33 pm

Hi, I’m thinking of doing my crawl space with low pressure, closed cell foam.
Currently I have older batt insulation, but it’s turned into a mouse-condo, so I’m ready to remove and replace with foam…DIY.
The crawl space is quite low… about 30″ from floor to joist. I have two vents (10″ x 15″) on either side of the space plus the access port (30″ x 26″).
I’m pretty handy with a spray gun, but I am concerned about being overwhelmed by fumes. Will I be ok with a proper respirator or in such a close space will I need to increase ventilation as well?
Also, what if I see mold areas of the joists…does it have to completely removed before spraying?

Thanks

Reinhart

Reply

Karie Fay September 12, 2013 at 11:22 pm

Hi Reinhart,

Good question. There’s many concerns with DIY spray foam insulation in the manner you propose. First, the chemicals must be mixed exactingly or the foam can fail or continue offgassing even after it cures (Not Good!). Second, it takes some skill to install it in an even layer at an effective depth. It takes special equipment. And yes, while it’s being installed the gas and smell is extremely noxious. Some people can’t take spray foam at all — even once it’s cured and they simply live in the home that contains it. IF you take all the safety precautions — including a special respirator and protective suit — and you have enough ventilation you should be okay. Still, I can’t suggest it. Too many risks and too much can go wrong.

I hope this information helps,
Karie Fay

Reply

George September 1, 2013 at 12:17 pm

I have a wet/dry dirt crawl space underneath a 1968 home. My house is on wood and concrete blocks. There is water damage and mold damage underneath. Inside the home there is no insulation in walls. I have eliminated the water spots, and as of now working to remove the mold and clean up the space . My concern is this: Is it possible to put a moisture barrier such as plastic underneath to protect from cold air and moisture in winter-and apply foam insulation?

Reply

Karie Fay September 12, 2013 at 11:18 pm

Hi George,

Is your crawlspace vented or unvented? With a heated or unvented crawlspaces, the walls of the crawlspace are typically insulated. Vented/ unheated crawlspaces insulate the floor above instead.

Either way, it IS important to remove all that mold. It will continue to eat at what it’s growing on otherwise. Next I would suggest laying plastic sheeting across the ground in your crawlspace. If you use more than one piece, overlap the seam generously. Setting a few bricks, rocks, or some sand on top holds it in place and sand protects it some as well. This plastic prevents ground moisture from coming up through the soil.

There’s no need to use plastic under or over the foam. Foam won’t allow moisture to pass through anyway. You might run it up the sides of the crawlspace — again with no holes or open seams through which moisture can travel — although the presence of wood concerns me. Is it treated wood? In what condition is it?

As for the foam. I would point you toward a closed cell foam, it costs a little more than open cell but it will work better. You can either install a layer of spray foam by itself (about an R-6 per inch of depth) or line the area with rigid foam, then cover it with spray foam. I tend to recommend this because if you do the work yourself, depth and evenness aren’t as critical as if the spray is used alone. I still suggest a professional installer, however.

Hope this helps,
Karie Fay

Reply

russell lewis August 11, 2013 at 3:49 am

i have an old stone house in italy and it has the original black stone roof. Rain has been coming through a few gap at the top of the roof. Can I spray foam to fill the holes. Which would mean the foam is partly exposed to the sun – which can hit about 38centigrade (100f). I’m not too fussed about it degrading over time, as it’s a stop-gap job until we sort the roof properly. My concern is if the exposed foam could ignite in direct sunlight.

Reply

Karie Fay August 17, 2013 at 11:28 pm

Hi Russell,

I wouldn’t have any concerns about the sun overheating the foam. It would have to get much, much hotter than that for it to ignite. As you mentioned, it will degrade over time — especially when exposed to the sun, wind, rain etc. It will seal the hole, however, and it’s great for insulation of course.

Good luck with your beautiful-sounding old stone house!
Karie Fay

Reply

Max August 7, 2013 at 7:07 am

I am considering toing my crawlspace myself with the spray kits. I know they are expensive but was thinking about adding a layer of ridigid foam insulation against the underside of the floor before spraying the foam. So this would give me layers of: floor-rigid foam-spray foam (from top to bottom). I was thinking it would be much cheaper to do it this way and the spray foam would still seal all the edges and such as it would without the rigid foam.

Is this advisable, is there something I’m not thinking of (foams are incompatible for ex: rigid foam is open cell and would trap mositure, they are different materials and spray foam would eat into the rigid foam, etc..?)

Any advice would be great as I would like to get started on this by doing section at a time .. .it’s not cheap and the winter will be here before we know it.

Thanks.

Reply

Karie Fay August 9, 2013 at 1:08 am

Hi Max,

Excellent question. Personally, I don’t see a problem with it. Against metal roofing you can place fiberglass batts and cover that with spray foam. I would think rigid foam would work just as well. I would suggest securing the rigid foam independent of the spray foam. You don’t want its weight on the spray. Go ahead and tape the seams as well. Also, spray a deep enough layer to create an effective barrier.

Good luck!
Karie Fay

Reply

Patricia July 31, 2013 at 5:03 pm

If the spray foam should not be exposed to heat, how can a attic be done, it gets so hot in there because the roof is right there. Also will the foam expand and dent my roof tiles?

Reply

Karie Fay August 2, 2013 at 11:31 pm

Patricia,

Good question. An attic doesn’t get hot enough to ignite spray foam insulation. It does get extremely hot, but still not hot enough to cause ignition of most items. A water heater flame, on the other hand, or other sources of extremely hot heat or flame will. Also, once it’s installed, it will be significantly cooler in your attic if the attic is relatively sealed and air-tight. The biggest challenge is applying the foam in an attic — high temperatures make foam cure very quickly and it may not cure properly.

Hope that helps!
Karie Fay

Reply

Susan July 25, 2013 at 6:01 am

Can the spray foam be sprayed on the “cold side” of the cavity?
-we want to remove the drywall and spray the exterior walls with closed cell so we won’t need a vapor barrier. Is this the proper way?

Reply

Karie Fay August 2, 2013 at 11:27 pm

Hi Susan,

Thanks for the question. If you’re not using any other insulation you can use just the foam. Obviously it would run from the “cold side” to the “warm side” of the wall cavity this way. It’s a vapor barrier at a given thickness. so you wouldn’t need to hang plastic or anything else on the warm side.

If you’re wanting to save money and use two types of insulation, however, you really need to put the foam on the warm side. A stone wool insulation batt, for instance, covered with a couple of inches of foam (then topped with drywall or other wall sheathing) works extremely well.

Hope I understood your question right and the information helps!
Karie Fay

Reply

Laura July 22, 2013 at 12:18 pm

There was some over spray that landed on the wood trim of my window. The gentleman applying the insulation told me to use a non-acetone polish remover to get it off….it didn’t work. Not at all. Any ideas? The wood trim I’m talking about is over a hundred years old and a beautiful patina has developed….now there’s dull yellow spatter all down one side. Help!

Reply

Karie Fay August 2, 2013 at 11:12 pm

Hi Laura,

Oh no! I hate hearing that. I so enjoy the look of wood, especially old wood which gathers so much charm and beauty. Have you contacted the company or gentleman who performed the installation? If not, I definitely would keep that in mind, in case you’re not able to get your wood looking the way it did. I also feel disappointed that it wasn’t wiped away while it was wet, when it would have done the least damage and wiped off easiest.

Acetone-based nail polish removers are commonly used to remove foam insulation. The acetone actually dissolves the foam when it’s uncured. Once it cures, it may not remove so easily. Instead, you may need to sand it off. I would try a nylon dish scrubbie or something similar first — even if it takes a lot of work, it sounds like you would prefer to keep the wood’s current finish. If that doesn’t work, sanding will remove it. Depending on the size of the area maybe you can sand just enough to remove it without completely refinishing the whole thing.

I would also call the company and tell them what happened. They should have ideas, and you have every right to be dissatisfied with it dripping on your antique wood. Sometimes workmen aren’t as careful as they should be.

Good luck!
Karie Fay

Reply

dora June 11, 2014 at 7:55 am

You can also try turpentine pure gum mineral spirits. Works great on wood, and will actually clean your wood as well.

Reply

dora June 11, 2014 at 7:59 am

Laura, you can try to use turpentine pure gum mineral spirits. It will help with residue and also takes off sticky messes including tape, glue ect.and will not harm the wood! It actually used to clean wood. A must try. .

Reply

ronald wilder July 21, 2013 at 11:54 am

I was talking just recently with a government building surveyor and retired architect and he added a very interesting fact that has nothing to due with insulation and pest suppression. He referred to a test that was don to determine the effects of wind on a structure using a jet engine. The structures that had been spray foamed held together and far exceeded the other construction methods. The foam, it seemed, added a “gluing” effect to the building that resulted in holding it together better than the other conventional methods. One more benefit to spray applications. Also I have seen fire retardant formulas on the market now available with some of the spray kits.
I am redoing my house in Florida and intend to foam as much as I can to take advantage of all the benefits of this product. For the people I was reading about with the crawl space problems spraying under the floor joists may be a better way to solve any insulation issues.

Reply

Karie Fay August 2, 2013 at 11:00 pm

Hi Ronald,

Very interesting information! It makes sense, however, when you think about it.

Personally I endorse using spray foam, rigid foam and fiberglass. There’s times when each form is perfect for the job. But there’s no doubt that spray foam is awesome stuff!

Good luck!
Karie Fay

Reply

Cindy Cooper July 15, 2013 at 1:07 pm

Can the spray foam insulation be stained after it hardens?

Reply

shane July 27, 2013 at 11:37 pm

No it is no recommended from what I’ve heard.

Reply

Karie Fay August 2, 2013 at 10:57 pm

Hi Cindy,

Please don’t stain, paint or otherwise coat your foam insulation. Two things concern me about that. First of all, foam can be flammable. I am afraid that adding yet more chemicals to it can be a fire hazard. Then there’s the fact that foam is a chemical, and adding yet more chemicals to it may cause a chemical reaction. Many solvents, glues and adhesives will eat away at the foam. You don’t want to spend all that money on the foam and then ruin it.

Why are you considering staining it? Have you cut the excess flush with the surrounding surface? If so, you can put wood trim over it and no one will ever know it’s there.

Hope that helps!
Karie Fay

Reply

george July 14, 2013 at 4:17 pm

what is the least amount of closed cell insulation i could spray to create a good vapor barrier, we have a seasonal motel and would not need the bennifit of keeping out the cold in the winter. just trying to keep the condensation and moisture down.
Thank you

Reply

Karie Fay August 2, 2013 at 10:52 pm

Hi George,

All you would really need, to create a moisture barrier with the foam, is a thin, even layer. Think of butter on bread — or even peanut butter — just a constant but thin coat. In order to be an effective vapor barrier, it can’t let in any air so the foam must be unbroken too.

That said, why do you prefer spray insulation to another type of vapor barrier? Using unbroken sheets of plastic is about the most affordable VB you can use and it works fine as long as you don’t puncture any holes in it and tape the seams as you hang it. And you say it’s a seasonal motel. Foam insulation will keep the hot out — not just in. Having lived in the south I know in warm climates they sometimes think insulation just isn’t important, but it is. I would really suggest either using a plastic vapor barrier or going thick enough with the foam to insulate as well. Even 1/2 to 1-inch-thick would do wonders.

Hope that helps,
Karie Fay

Reply

Meg June 18, 2013 at 11:14 pm

Is there a way to give the foam and extra water proffing if it has been used to fill gaps near doors and windows. Its already set up and trimed and not inplaces where dry wall van cover it. My slum lord wont do anything so Im trying! So far adding it has helped the kitchen stay cooler, but I am worried rain in the fall ( we are dry here in summer) will make all of it go away! I had thought about a spray on shellac to give it a seal but now and nit sure after reading this.

Reply

Karie Fay June 30, 2013 at 9:36 pm

Hi Meg,

Thanks for reading the article — I am glad it made you hesitate before coating your insulation with anything! I would be very concerned about any chemical or solution possibly melting the insulation or proving flammable — or worse.

Expanding foam insulation is already waterproof — you don’t have to worry about water ruining it, or leaking through it as long as it’s solid. It may leak AROUND the insulation, if you leave any gaps. Just make sure you completely fill the gaps and you should be fine.

Now, you say the drywall doesn’t cover it… Consider wood trim if appearance is an issue. Curtains should also work well.

Good luck with your efforts… I applaud you!
Karie Fay

Reply

mike r June 11, 2013 at 6:27 am

HI PEDERSON
CAN SPRAY FOAM BE USED ON A CRAWL SPACE FLOOR THAT IS ONLY A GRAVEL AND DIRT BASE

PLEASE REPLY

Reply

Karie Fay June 21, 2013 at 3:07 am

Mike,

No. It would really be a waste. You would be much better simply using sheets of rigid foam insulation to line the ground if you were determined to insulate it — it’s much cheaper. You should have a vapor barrier such as plastic lining your crawlspace floor/ground. Then, insulate the walls and ceiling rather than the ground.

Hope that helps,
Karie Fay

Reply

Mike May 13, 2013 at 2:05 pm

My Contractor got spray insulation on my new fiberglass Pella door and it dryed.. Is there anyway to remove it? I am holding up payment until it is clean..

Reply

Karie Fay May 19, 2013 at 12:12 am

Hi Mike,

Ouch! I would be pretty upset with that contractor! Have you informed him of the problem? If you haven’t yet, you should. Personally, I think he should clean the mess as well. It would have been much easier to remove before it dried.

If you have to tackle this yourself, it might prove a little difficult. In general, the only way to remove expanding foam, once it has dried, is to mechanically remove it – scrape, sand, dig, etc. Knowing the last thing you want is to take the chance of marring your new door, I did look into the situation a little further. It appears that there are a few silicone and foam sealant removers that may work for you. Without recommending any specific product, I see that Mötsenböckers FSR Sealant Remover is designed to not exactly dissolve the foam, but rather loosen it from the fiberglass so you can pry it away without damaging your door. I am not seeing any other comparable products, but there may be some out there.

A suggestion – take pictures of the problem before you do anything. Then, if you still want to try to clean it yourself, document what you use and what you do. Shoddy work is never acceptable, so don’t be afraid to speak up.

Good luck!
Karie Fay

Reply

Mike May 9, 2013 at 4:57 am

This is true spray foam insulation does the job better than other choices. You have shared an informative and useful post, insulation is really a crucial thing for homes it can keep them warm in winters and cool in summer so we can reduce energy bills after installing it. Thanks for the informative post.

Reply

Chuck Kreps April 24, 2013 at 9:32 pm

Very interesting information. I was looking for a way to make my own insulation. I have a limited budget but this was all good. Recently I made my own wood treatment / green treatment only mine was pink saved $65 a gallon. Thanks for all the good insight.

Reply

Ted Dulka April 24, 2013 at 8:12 am

At what air temperate is spray foam insulation should be sprayed

Reply

Karie Fay April 25, 2013 at 9:48 pm

Hi Ted,

Good question. The answer is actually a little bit complicated.

In general, the *ideal* temperature for most expanding foam insulation products is room temperature — between about 75 degrees and 85 degrees Fahrenheit. However, some products can be applied at much lower temperatures and some can tolerate higher temperatures.

Air temperature isn’t the only factor either. Make sure the product temperature is at room temperature and the surface which you are insulating is up to the minimum temperature. If the surface temperature is adequate and the product temperature is sufficient, it’s more important than air temperature (although there is a relationship between the two typically). Applying the product outside of temperature requirements may cause the foam to under-expand, to not cling to the framing, to have less R-value, or other undesirable consequences.

Your best bet is to look for a product that allows application in the temperature range you require. It will be listed in the instructions and on the label.

Hope that helps!
Karie Fay

Reply

Ted Dulka April 24, 2013 at 8:10 am

At what air temp

Reply

Bob April 15, 2013 at 12:05 pm

In my an attic installation (Region 4) that is 3 floors above a gas furnace, can the spray foam be applied around the furnace vent where is passes through the roof? If not, what material can I wrap or install around the vent (e.g. mineral wool), against which I will spray the foam? How much leeway should I plan for furnace vent expansion/contraction where I spray the foam?

Thanks in advance!

Reply

Bob April 15, 2013 at 11:30 am

In an attic installation (Region 4) that is 3 floors above a gas furnace, can the spray foam be applied around the furnace vent where is passes through the roof? If not, what material can I wrap or install around the vent (e.g. mineral wool), against which I will spray the foam? How much leeway should I plan for furnace vent expansion/contraction where I spray the foam?

Thanks in advance!

Reply

Karie Fay April 26, 2013 at 12:15 am

Hi Bob,

There are spray foam formulas that can withstand higher temperatures (and likely at three floors above a gas furnace, that vent is not very hot anyway). That said, I am just not comfortable with advising your situation. Your safety is just too important.

I will say the typical way to treat it is to install flashing cut just enough to allow your vent to travel through. Seal the gap between the flashing and the vent with high-temperature silicone caulk to prevent vapor transference.

Next, cut a piece of aluminum long enough to wrap around the vent plus about 6 inches. Cut the top and bottom edges with slits 1 inch long and about 1 inch apart. Bend these tabs in at top and out at bottom. Fit around your vent, maintaining the 1-inch clearance the top tabs create, and secure with tack nails at the bottom (covered with silicone). Then feel free to insulate around the barrier however you wish.

I would suggest looking at your local building code or consulting with the local building code department. They can provide more information applicable to your area.

Hope that helps!
Karie Fay

Reply

Huguette March 29, 2013 at 7:04 pm

I have old 1975 aluminum window frames that badly conduct the Canadian winter cold air right through into my home making it very difficult to warm it up. I am considering drilling holes in my aluminum frames and spraying foam into them. My concerns is about the flammability of the spray foam. When the sun beats on these windows they get hot. How would it affect the spray foam inside the frames???

Reply

Karie Fay April 25, 2013 at 9:38 pm

Hi Huguette!

Thanks for the question. In my opinion, the window area doesn’t get hot enough to pose any fire hazard. In fact, expanding foam insulation typically will not burn unless exposed to an open flame. The greatest danger heat poses to spray foam is melting — it’s actually a plastic, and like all plastics, if the temperature is too high it will melt. At the melting point it will also release toxic fumes. This is the major concern of exposing spray foam to high temperatures.

That said, the melting point is somewhere around 400 degrees Fahrenheit. I doubt your window frames ever get that hot. I would suggest using cans of window and door formula expanding foam — it expands a little less than regular expanding foam in a can so it’s a bit of a safeguard against overfilling the framing around your windows.

I would also encourage you to take your steps a little further as you can. Are your windows single pane glass? Do you have storm windows? In those cold Canadian winters every bit of air sealing you can do to your windows — and your entire house — will impact your heating bill tremendously. Feel free to look at my article on the subject. Just click my name to the right and there’s a list of topics.

Hope this helps!
Karie Fay

Reply

Sue February 20, 2013 at 9:16 pm

I replaced vinyl windows two 2 years ago, the contractor ordered them slight smaller
Used a lot of calk, the 1st year was ok but this second year I’m seeing daylight thru gaps. Can I use spray foam safely around my windows without binding them or damaging them. What would you recommend?

Reply

cody February 26, 2013 at 4:00 pm

yes you can just make sure that the can of foam is ment for windows and doors they generally dont expand as much as the others thus no binding.

Reply

Karie Fay March 11, 2013 at 9:05 pm

Hi Sue,

Caulk is not the way to go. I would dig all the old caulk out and replace with spray foam insulation from a can. Easy to find in the store and super easy to apply. As Cody mentioned, just make sure you get a formula that either says “Windows and Doors” or possibly “Low Expansion.” Since they don’t inflate as much as other formulas, they won’t damage your window or window frame. Then, when you’re done, use a utility knife to shave the excess from the area.

Good Luck!
Karie Fay

Reply

Stevenson Building Products January 16, 2013 at 7:28 am

Something to keep in mind especially in the winter months, is that spray foam needs moisture to properly cure. It may look cured at first glance but if you dig into it you may find that it is very “airy” and brittle. To avoid this, lightly mist the area you are foaming with a spray bottle prior to applying the foam. This will allow for a proper cure. Another important note is to keep the spray foam at the recommended temperature!

Reply

Car insulation January 13, 2013 at 7:22 pm

It’s the most efficient and cost-effective insulation that you can put in your home. Made from 2 liquids which react to become a foam, expanding 20-30 times their liquid state-filling cracks and difficult-to-insulate places.

Reply

Pedersen January 6, 2013 at 3:06 pm

Can this type of insulation be sprayed directly onto the concrete block walls in a crawl space? Our 30+ year old home had the crawl space insulated with standard fiberglass roll insulation and it’s deteriorated and falling down and needs to be replaced.

Reply

Karie Fay January 25, 2013 at 5:32 pm

Hi Pederson,

You’ll find two camps when it comes to spraying concrete crawl spaces with spray foam. One side prefers spray foam or rigid foam to the exclusion of any other choice. The other side says never.

The problem is, if moisture seeps through the concrete block (which is naturally absorbent) and becomes trapped between the concrete and insulation, it has but one choice — to stack up and eventually leach into your wood house framing above. This leads some people to use fiberglass instead — which can also rot.

My suggestions: First check with your local building authority and find what they suggest and what R-value you need for your area. Assess your crawlspace and see how damp it is. If it is damp, you may be able to encapsulate it (use sheets of moisture barrier on the walls and floor, at minimum) to prevent moisture. Once you seal everything properly, and if local code allows, then spray foam is an excellent choice. If you have a very dry crawlspace already, you’ve got it made.

Hope that helps!
Karie Fay

Reply

Aaron January 2, 2013 at 11:28 am

Can you use spray foam to seal the vent connector that goes directly into the chimney from an oil furnace, or will temperature exceed the foam’s capabilities? it is just a single walled vent connector that runs from the furnace to the chimney, it does get quite hot, too hot to touch when running

Reply

Jay January 23, 2013 at 3:43 pm

Aaron what part of ignites quickly did you not understand? Spray foam absolutely cannot be used to seal chimneys and/or furnace vents pipes!!!!!

Reply

Karie Fay January 25, 2013 at 5:07 pm

Hi Aaron,

No, I wouldn’t put it anywhere where the temperature exceeds normal environmental temperatures (a 125-degree attic is okay, in other words, but not in a vent or chimney). Spray foam of any form is highly flammable and emits toxic fumes as it burns. In any residence, you must cover it with a fire-rated covering such as drywall. I also am concerned about sealing a vent connector. Please make sure that this is safe — a furnace repair service can advise you on that.

Hope this helps!
Karie

Reply

Tony Scott December 20, 2012 at 4:22 am

This blog has presented some useful tips regarding the usage of spray foam insulation. Applying these steps will help in checking unwanted air and moisture from entering your home.

Reply

Anjaleena October 4, 2012 at 9:24 pm

I would recommend professional installation, but even DIY installation can be quite successful if planned properly. Specialized training is required before attempting a DIY installation of spray foam equipment.

Reply

Leave a Comment

{ 1 trackback }