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Ask Woodiwiss: My house has structural damage. How do I repair and repaint walls after a flood?

We hope it never happens, but a flood can come from nature, an overflowing toilet, a failed sump pump, or a busted dishwasher. It’s rare that water heaters “burst”, but some older models can suffer structural damage that causes them to collapse, too. The result is flood water in the kitchen, the bathroom, or the whole house. Water-damaged drywall, badly warped hardwood floors, and a risk of mildew or mold are all top concerns.

What to do immediately after a flood or water damage

Depending on the amount of water and your ability to control it, your first job is to:

  1. Turn off the power in the affected area if there’s even a slight risk the outlets or electricity are exposed to moisture.
  2. Wet-vac or push out the excess flood water. Obviously, a natural flood is no match for a wet vac or some towels, but if it’s smaller in scope, get the standing water out.
  3. If you’re in the kitchen or have cabinets, open all the doors to let air circulate.
  4. Open the windows and use floor blowers, box fans, and anything that can maximize air circulation. Special carpet-drying air movers are relatively cheap at hardware stores. And if that means turning the heat or air conditioner on even on a pleasant day with the windows open, turn it on.

Depending on the amount of water, drying everything out may take a few hours or even a few days. Proper drying is critical for reasons we’re about to cover and will ensure excessive moisture doesn’t creep further into grout, floor tile, or wooden floors.

Prepare a mildew surface cleaner to clean up what you don’t see yet

Surface mildew will be easy to spot if it starts to form, which may appear in some climates within a couple of days in the summer. Scrub floors with a mild surface mildew detergent or cleaner. Chlorine bleach mixed with water works great so long as you wear rubber gloves and have enough ventilation to breathe. One-quarter cup bleach with a gallon of water is a good ratio.

Bleach and many mildew cleaners can damage the colors of wood floors or carpets, so proceed cautiously and read the cleaner’s labels. Carpets and pads soaked with contaminated flood water are probably worth removing and replacing. 

Once carpets are removed, clean the subfloor with a good disinfectant to prevent mildew build-up before replacing the flooring. You may need to sand hardwood floors level depending on the wood’s exposure to moisture if it warps.

The water is dried, but what about the paint and walls?

After a flood, most people focus on the floors. But you need to disinfect the walls, too. Paint and drywall are slightly porous, so unless rapid and sudden drying is possible in small areas, your walls have likely absorbed the water like sponges.

If the flooded area was exposed to water for less than a few hours you can probably get away with drying the walls. Wait a few days to see if surface mildew appears, and if it doesn’t, you can either paint over the surface or clean it again and let it dry.

If the flooded area was underwater for a long time, mold and mildew can begin to form in the damaged drywall. You’ll need to remove the wet drywall down to the exposed wall cavities and all the flood-damaged insulation.

While the wall cavities are exposed, check for damage to interior spaces, electrical outlets, wiring, and any drywall screws that may start to rust. 

After you’re convinced everything is appropriately and thoroughly dried and no further damage is likely from mold and mildew, replace the insulation and drywall and repaint the walls. For extra protection, you can use paint with a mildew-resistant finish. These paints don’t kill existing mold growth so much as they smother it.

Contact professionals if you’re unsure about anything

Water-damaged drywall can pose a severe permanent health hazard, especially for children and older adults. Professional cleaners can use a phosphate cleaning solution and commercial dehumidifiers to dry floors in an affected area. You should lean on that experience and expertise.

We’ve helped restore homes after flood-damaged walls developed bubbling or peeling paint — a sure sign water is behind the paint layer. You often have no idea how sneaky water can be and where it can hide.

Consult your homeowner’s insurance policy for possible coverage that can help, even if the flooding was caused by a failed appliance or plumbing issue. 

It’s cheaper and easier to deal with the damage properly all at once as it happens rather than waiting to see what, if anything, develops. Water-damaged drywall can retain moisture for weeks or months, rot, and cause more headaches as you repair and repaint it, only to rip it all apart again.

If you’re facing flood-damaged walls in your home, contact us in the East Bay area to get started with a permanent solution to restore your home like new.