Water can infiltrate the framing, flooring and other woodwork in your house in several ways. It can come from a plumbing or roof leak, it can collect as condensation from humid air or it can be the result of a flood. Bad things happen to wet wood, but they don't happen immediately, so you usually have time to dry out the wood before permanent damage occurs.
Remember this at the outset: Wood can't dry out if it is covered by something wet or if water incursion is still occurring. You have to expose wet wood so air can circulate around it and address the source of the moisture before the drying process can start.
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Some Water Damage You Can See and Some You Can't
If you have an active leak, or a flood just occurred, you won't have any trouble spotting wet wood. Some problems are not obvious, though, and reveal themselves only through related damage. Moldy or sagging drywall is the most obvious sign of water-damaged wood, but there are others, including visible congregations of ants.
Water flows downhill, so if you've experienced a minor flood or a leak, the most likely place to check for damage is the bottom of walls and cabinets. Floors are especially vulnerable to moisture. If water seeps underneath the floor covering and infiltrates the subfloor, the resulting rot can create sponginess.
Condensation from high-humidity air can create wet wood all over the house. It can make passage and cabinet doors swell, and it can warp door and window casement molding. Before structural damage occurs, dark patches of mold usually alert you to the problem.
The Damage Water Can Do
If you've recently suffered a flood, you may still have standing water on the floor. The Red Cross advises care because the water may contain pathogens and other unhealthy contaminants, not to mention that it just makes everything dirty.
Whether or not the water is actually pooling on the floor, it is providing nourishment for mold, rot and fungus, and if the moisture has been there for a long time, the colonies may be advanced. Drying out the wood is the best way to kill the colonies, but until that happens, you should avoid inhaling the air. Wear a mask.
Mold remediation is an inevitable part of damage control after an extended period of moisture exposure. You don't have to wait for the wood to dry out to remove the mold, but drying is necessary if you don't want the mold to return.
Dealing With Mold
Mold is bound to grow on any wood that gets wet, and mold remediation is a necessary part of any flood cleanup. The first thing to remember is that the Environmental Protection Agency recommends professional cleanup for any mold infestation that exceeds 10 square feet. Pros have the necessary tools and know-how, and they'll also be able to help with the drying process.
For localized mold problems, the recommended procedure is to physically scrub off the mold with detergent and water. Bleach isn't necessary because its high surface tension prevents it from penetrating wood and killing the roots. You can use bleach if you want at a concentration of one part per 10 parts water.
A better way to disinfect wood and prevent mold from growing is to apply borate wood treatment powder. This is especially good for wall studs and plates that have gotten wet. Dust the borate powder liberally on the dry wood before replacing the insulation and drywall.
First Step for Drying in a House: Remove Standing Water
Water that has pooled on the floor after a flood or a large leak has to go. The best method for removing it depends on how much there is. In some cases, you may be able to squeegee it into a corner and pick it up with a mop or sponge, and in others, you may have to pump it out.
A wet/dry vacuum comes in handy for clearing standing water, especially when you need to get it out of cabinets. Simply vacuum the water into the canister, empty the canister outside and clean up the residue with a sponge. You can also use the vacuum to suck water from underneath cabinets and wall plates.
Second Step: Expose the Wood
If the framing in your house or any other structural wood gets wet, anything touching it, such as drywall and insulation, is also wet. The wood won't dry out unless you remove the wet material covering it.
Take down any drywall that appears wet to expose the framing behind it and pull out the insulation. Remove any carpeting covering a wet hardwood floor. If you suspect water damage to the subfloor, remove the floor covering to expose the subfloor. This may involve a lot of work, but if you don't do it, you risk far more expensive repairs in the not-too-distant future.
When a leak occurs inside a kitchen or bathroom cabinet, remove everything from the shelves and take out as many shelves as you can. To promote air circulation inside the cabinet, it may also be a good idea to remove the doors. Don't forget to fix the leak.
Third Step: Circulate the Air
Open doors and windows in the room to create a cross draft as long as the weather is dry and not too cold. Turn on any available exhaust fans and bring in as many portable fans as you can find. Set these at floor level to circulate air at the bottom of the walls and cabinets, which are the most likely to be wet.
Some remediation pros recommend buying or renting a carpet fan to speed up the drying process. This type of fan is designed to blow an extra-strong stream of air at floor level where you need it most.
Fourth Step: Provide Heat
Water evaporates more readily in warm air, so the more heat you can add, the faster the wood will dry out. Use electric heaters, not propane ones. Moisture is a byproduct of propane combustion, so while large torpedo heaters may provide a lot of heat, they increase the room humidity and slow down the drying process.
During the winter, you will want to keep the doors and windows closed – or at least most of them – to help retain heat. It is a good idea to open a few windows upstairs, though. Heat rises, and if it has a way to escape, the resulting updraft will hasten evaporation.
Fifth Step: Run a Dehumidifier
A dehumidifier works best in a closed space, and you should definitely run one if the wood you are trying to dry out is in the basement or in a bathroom. It may not help much in a large, airy living room, but you probably won't need it there anyway.
A dehumidifier can be a big help with kitchen or bathroom cabinet water damage. Air doesn't circulate well inside a cabinet, but it doesn't have to for the dehumidifier to suck out the moisture. Set it at the opening of the cabinet and run it at full power.
Handling Wood Rot
Like mold, rot is a microorganism that needs moisture to survive. When you uncover a wall that has been wet for an extended period, you are likely to find rot in the studs and the wall plates, especially at the bottom of the wall.
It goes without saying that the wood has to be dry before you cover it back up. You can use heat, air circulation and a dehumidifier to speed the drying. Once the wood is dry, apply borate wood treatment powder to kill the rot fungus and prevent more from growing back.
Rot damage often requires replacement of the wood, but you may not have to go to that much trouble. You can use epoxy resin wood filler to make repairs. Dig out the rot with a chisel or screwdriver first, and then fill the cavity with the filling material. If you don't have epoxy filler on hand, auto body filler also works.
Water Leak Under Cabinets
Flooded cabinets in the kitchen or bathroom present a particular challenge because water usually seeps through the bottom of the cabinet onto the floor. The resultant rot can destabilize the cabinet, and mold creates a health hazard.
You may have to remove the toe kick or the bottom of the cabinet to gain access to the area underneath the cabinet. If you can't do either, it's best to move the cabinet if that is feasible.
Use a wet/dry vacuum to suck out standing water, and then use a sponge mop to clean up the residue. Point a fan under the cabinet and leave it there for one or two days to dry out the floor. After that, make any necessary repairs before covering things back up again.
Water-Damaged Plywood and Particleboard
In a high-moisture kitchen or bathroom, condensation can wreak havoc on cabinet sides and doors. It causes plywood to delaminate and particleboard to swell, and, of course, it promotes mold growth. Once delamination or swelling occurs, replacement of the wood is usually the only option.
The signs of impending damage are usually evident in brown or black discoloration on the cabinet facing. When you see this, wipe off the mold with soap and water, and then run a fan, heater or both to dry things out. If you have a chronic problem, look for ways to improve air circulation around the cabinet.
Window and Door Casings
If you live in a part of the world with cold winters, you may have a problem with condensation forming on the window and door trim. The moisture promotes mold growth and may even warp the trim. This happens because the temperature gradient at the door or window condenses water out of the warm inside air. It wouldn't happen if the trim were better insulated.
Improve insulation by removing the casing and blowing spray foam insulation into the gap between the door or window frame and the wall. You can also stuff fiberglass batt insulation into the gaps, although this isn't quite as effective. Block drafts by applying weatherstripping to door and window jams. Replacing single-pane windows with double-pane ones also helps if your budget allows.
You might also consider improving air circulation around affected areas by using a fan. This might not be practical if your house is cold and you're trying to make it warmer, so an alternative is just to wipe off condensation with a rag once a week during the coldest months.