Repairing Water Damage in Your Home

If left unrepaired, water damage will continue to worsen, leading to greater problems. Learn what you need to know about water-damaged home interiors and how to tackle the situation appropriately.

First, you must find and fix the water source. Depending on the situation, you may need to hire a professional to repair plumbing or roofing. Then you can proceed to drying up any water present, sorting through items, and repairing the water damage.

Signs of Water Damage

  • Odors - Standing water stagnates. Rotting wood emits an earthy smell. Mold and mildew smell much the same. If you enter a room or open a cabinet and notice a musty, peculiar smell, it’s likely you not only have a water leak somewhere, but damage has occurred.
  • Fuzzy, discolored growths - It’s not a reflection of poor cleaning habits. Mold spores float through every waft of air inside and out. If they encounter a moist, dark area with a food source – which includes most building materials – mold, mildew and fungus will thrive. Within 36 to 72 hours, it’s entrenched. The longer it grows, the worse it gets.
  • Stains and discolorations - Brownish and dark stains on your ceiling are a sign of a leak. Walls and floors may also discolor. Whenever unexpected stains appear, check for a water leak in the immediate area.
  • Blistering or peeling wall surfaces - Water invading the wall material may cause paint to lose adhesion and separate, either blistering or peeling. Wallpaper, plaster and other wall coverings may act the same.
  • Damaged walls and ceilings - Beyond stains and the appearance of the wall sheathing, the wall or ceiling itself may begin to fail. The wall may warp or buckle, and the ceiling may begin to sag. Whenever the surface itself becomes soft and spongy, it indicates a definite problem. Drywall (the most common wall material) absorbs water easily and begins to swell and disintegrate. Walls or ceilings made from lath and plaster don’t fare much better.
  • Damaged floors - Buckling, cracking, cupping (curving at the edges) or soft flooring are a likely signs of water damage. Investigate changes in your floor immediately.

If you’re uncertain whether you have a leak or simply want to confirm your suspicions, consider using a moisture meter on your walls, ceilings or floors. Simply follow the manufacturer’s instructions to take the moisture reading. You can also use moisture meters to measure the water content in building materials for home remodeling.

Repairing Water-Damaged Structures and Materials

Every situation is different. If the water damage arises from a flood, for instance, it may not saturate the wall. Perhaps all you will need to do is tackle the floodwaters and repaint the wall to cover any surface staining. A leaking pipe inside a wall, in contrast, may cause it to rot from the inside out. In that case, you are looking at more extensive repairs. Even in the case of flooding, you must evaluate the type of floodwater and determine how to remove the water. Once the water or moisture is gone and the source is fixed, the damage can be evaluated. Repairing the area then depends on where it’s located and the extent of damage caused.

Mold and Mildew - Painting or otherwise covering mold and mildew won’t kill it. It can continue to spread unless it is removed. Worse, even “harmless” molds (in contrast to toxic “black mold”) can affect your health. Tackle mold with a solution of 1 part bleach to 8 parts water. Spray the mold or mildew first, wait 10 or 15 minutes, then wipe or scrub away. For a more natural mold-cleaning solution, use either straight vinegar (which kills 82 percent of molds) or a mixture of vinegar and baking soda. Rinse thoroughly and dry completely before proceeding with any further work on the affected area.

Discolored Paint - When damage is minimal and only the exterior of a wall or ceiling is affected, once it dries out, it will probably leave a stain. Use a stain-blocking alkyd-based primer to seal the stain before painting. Remove any peeling or damaged paint first to ensure the best results.

Damaged Drywall - If the drywall is exposed to water for less than two hours and the water is clean (not mixed with sewage or other contaminants), you may be able to save it. After a couple of hours, however, drywall becomes saturated. The problem is worse if it’s on the ceiling. Drywall is heavy by itself; when waterlogged, it grows even heavier and may begin to bulge or fall. If you have any doubt about the drywall’s structural integrity, place a level across the surface and see if it is either plumb – straight up and down – for walls, or level on ceilings. Next, try pushing a small finishing nail into the drywall using your fingers alone. It should meet immediate resistance. If the surface feels spongy or the nail sinks in easily, replace the drywall.

To replace damaged drywall, first determine how far back it needs to be removed. A leak from a pipe may need only a small section of drywall removed to access the pipe and fix it. In a flooded bathroom, on the other hand, you may need to remove the drywall around the entire room from the floor up 18 inches. Use a utility knife and a straight edge to mark and cut your wall sheathing. End in the middle of a stud on either side of the opening to provide an anchor for the new drywall.

Remove any insulation in the wall (see the section on insulation) and dry out the wall interior. Only once the inside is completely dry should you patch the drywall. Replace insulation if removed, using new material. Cut a piece of drywall to measure the dimensions of the opening. Attach with drywall screws every 16 inches apart along each stud (12 inches apart for ceiling drywall). Tape the seams with drywall tape and cover the seams and screw heads with joint compound or mud. Apply thin, even layers and sand between each. Feather out each layer of mud a little farther than the last to make a seamless appearance.

Sodden Plaster Walls - If your walls or ceiling are made with lath and plaster, as is more common in older homes, there’s good news and bad. Typically, the plaster holds up better to saturation than drywall, but it can take much longer to dry out. Loose plaster, advises the North Carolina Department of Cultural Resources, may be able to be reattached with plaster washers. Plaster ceilings can be temporarily supported with braces made from two-by-four lumber in the shape of a “T” (place the top of the T against the ceiling).

If the inside of a plaster wall is wet, remove baseboard trim and drill holes in the wall to allow water and moisture to escape. Use hand drills or cordless drills to avoid the risk of shock, and stay clear of wiring or other lines in the wall. Pull out any insulation and set up fans to encourage ventilation. Repair the holes only once the wall interior is completely dry – a moisture meter helps tremendously. For extensive plaster and lath damage, consider replacing the entire system.

Wet Insulation - While tearing your wall apart you may discover insulation, especially if it’s an exterior wall. Always remove the insulation. First, it may hide damage to the studs. Further, wet insulation deteriorates. It may compact, disintegrate, lose R-value and even harbor mold or other contaminants. Although rigid foam insulation may be salvaged, it’s generally easier – and safer – to replace insulation with new material.

Stained or Rotted Studs - If you’re lucky, your wall studs are solid. Push on them and try driving a nail into them if you have any doubts – the last thing you want is a structural failure, especially if it’s a load-bearing wall. Exterior walls are always load-bearing. Some interior walls may be as well. Load-bearing walls support the weight of the structure above and surrounding them. A weak or failed load-bearing wall may cause the home to collapse. If the studs of a load-bearing wall are rotten, consult a professional immediately. For walls with rotted studs that are not load-bearing, cut out the bad studs, one at a time, and replace them. If you find studs that are stained but still solid and don’t need to be replaced, spray them with a dilute bleach water mixture. Follow with an antimicrobial solution, available in hardware and home improvement stores.

Water-Damaged Floors - If the leak is under your floor or if the floor got wet from a flood, you’ll probably have to strip it down to the subfloor. Water and excessive moisture ruins carpet and padding, seeps under floating floors, dissolves the bond between tile and the subfloor, and works its way under vinyl and linoleum. Depending on the amount and source of moisture, you may be able to simply dry out some solid wood floors. Although it swells and buckles slightly, as it dries it may return to normal, especially if weighted down while it dries. Always dry wood slowly to avoid damage – don’t try to super-heat or cool the air to dry it rapidly.

When you get down to the subfloor, mark out the area you wish to remove. Use a straight edge to create the outline, and enlarge it as you cut through the floor, to end in the middle of a floor joist (this provides an anchor for the floor patch). Punch a hole in the middle of the area to be removed, and gradually cut it larger in order to watch for pipes, ductwork or wiring running underneath the floor.

Piece in a new subfloor, once the area has dried and the insulation has been replaced. Use screws to anchor the subfloor patch to the joist and thus prevent squeaking floors. Cover the subfloor with your choice of flooring materials.


Brittany - February 3, 2015 at 9:05 am

My husband and I saw a forclosed home this weekend with our realtor. We are trying to decide whether or not the damage to the house is more than we can take on. While looking at the house we noticed hairline cracks at almost all the edges between the wall and ceiling. There was one spot on the ceiling close to an exterior wall where we noticed a very small stain from water. Also, there was a spot where an interior bedroom wall met the ceiling that had paint chipping away. After reading this article, I know what this means… But are we looking at small amount of damage and minimal expense or does this sound like it may have extensive damage and repair costs (like the roof needing replaced)? Sadly, this has been the best house we’ve seen in our are that is in our price range, so we have to be realistic with the repair costs.

Cee ntim - January 8, 2015 at 2:00 pm

I have a house in west africa Ghana and I understand the plaster is abd the painting
Is cheaping away, do do have any idea what I can use
To reduce this problem?. Is flaky.

Chuck Guill - December 9, 2014 at 1:32 pm

In 2009 we had major renovation of exterior buildings, siding, stone work ect. On the ends of these buildings, on the inside walls, the sheet rock is buckling mostly at the top plate between first and second story but I do not notice water penetration,. Could this be caused by the cold air outside meeting warm air inside causing frost or condensation to build up between walls. I reside in upstate NY…

Malcolm Thomas - November 4, 2014 at 10:12 am

One of my bedroom walls was damaged due to a valley problem in between ny 2 roofs where the lesd had lifted.
The lead has now been replaced.
However due to the damageon the wall, the paper is coming away from wall.
Should I cover the wall with plaster biard and re-wallpaper, or can you advise alternative.
Many thanks.

esther - October 2, 2014 at 4:58 am

I live in a rented apartment in warri nigeria, anytime it rains water comes from under the floor and the whole bedrooms, kitchen,sitting room and balcony gets flooded as a result of water coming out from under the floor. Please what could be the cause and what can be done if repairs are to be made? Thanks.

Josie L - August 27, 2014 at 6:43 am

Such great tips and thanks for the explanation! Our house just recently got flooded. Unfortunately, we weren’t home and most of the furniture and items we had in the basement had to be disposed. We also got mildew/mold, stains, damaged walls and floors, and of course the smell! (Yuck) I was so glad to see so many tips online (one I looked at). I think without all of these suggestions we would have been lost! We acted quickly when we returned, we got all of our stuff out. We cut/tore out wall-to-wall carpeting, some storage cardboard boxes with out stuff in them – they couldn’t be salvaged. Thanks for the “water-damaged floors” tip, this was very helpful.

Robin Hammond - August 10, 2014 at 6:58 am

My house is built on a sloping lot so you enter on the main level and go downstairs to the beds and baths. The top story is suspended on perimeter beams over a dirt basement type area, accessed from one of the downstairs bedrooms. The basement and the downstairs portion of the house share a common wall.

The downstairs portion of the house is on a slab. The basement is unfinished and not what I consider a true basement providing walk out or storage space. Rather there’s dirt (solid rock) sloping from the front of the house to the downstairs area with about a 5′ drop and then maybe 2′ path along the shared wall from side to side. My guess is the contractor (in 1950) didn’t want to bother jack hammering through the rock to level it out.

Now here’s the problem. In Texas, when it rains, it usually flash floods. When that happens my basement hill becomes a spring and water percolates in thru the rock. Therein the reason for the 2′ path which also serves as a trench to direct water to a collection area and a pump connected to exterior drainage. Many times the rain is so intense the trench can’t contain the water and it becomes a small stream that will seep into the house all along the shared wall.

Is there anything I can do to seal the dirt and rock to prevent the water from seeping into the basement altogether? Then where do I start to waterproof and seal the adjoining wall to prevent water from coming inside?

Laney Schram - July 22, 2014 at 4:40 am

After the winter, I found our basement full of mold on the walls and in the corners, and the whole basement was in a bad condition. I had to clean up and called up drain & waterproofing service in our place, Doctor Rooter Toronto, and they had a look-in and found a crack in our foundation and seems like the melted ice water came in through the cracks. They sealed the foundation and cleaned all the mold. They had these dehydrators to remove all the moisture from the air. Then had waterproofing installed, and everything was back to normal. It was a hectic week for us, but it seems pretty ok now.

carmen - June 17, 2014 at 6:10 pm

After a flooding damage in the ceiling, a non-structural divider beam along the ceiling, and the hardwood floor, a rather large hole was opened in the ceiling, the paint was peeled from the beam, and the floor was swiped dry. Afterwards, the hygrometer indicated a dry surface in all three places. I am however not sure whether mold is growing in the ceiling insulation, between the wood structure and drywall in the beam, and in the subfloor underneath the wood floor.

Is it possible to test the air inside the ceiling and sample the beam to assess whether mold is growing?

What can be done to test what is happening underneath the hardwood floor?

linda - May 11, 2014 at 12:44 pm

You mention how to replace a damaged stud. What if your exterior wall sheathing has sustained water damage. How do you repair/replace from the inside, without affecting the exterior siding?

CajunPatriot - December 15, 2014 at 1:01 am

If you can reach the damaged stud from the inside of the house/wall, then you can use a zip saw (Sawzall) to cut the stud into pieces to pry and hammer out to remove.

Sometimes, damaged studs or other solid wood do not need to be actually removed but rather treated with bleach and other sprays to kill any mold or mildew spores. Put a blower or fan on the area to dry it very well once it is sprayed several times over several days. If your damaged stud can be treated and not removed it is much less work and expense.