Back in the day, I had an hour long drive from the nearest Home Depot to my rural home in Missouri. More than once, I loaded up my trailer, failed at tarping it properly, and unloaded soaking wet plywood once I got home.
I’m now a pro at saving wet plywood. My process generally goes like this:
Wipe up any water on the surface of the plywood panels. Then move the plywood to a dry area with lots of ventilation. Prop the plywood off the ground, so air can circulate around it. This will allow the water to evaporate from the plywood, drying it out.
Loose planks of plywood that have not been wet for long will be easy to save. The same is not true for plywood that has been soaking for a long time or that is fixed into walls or floors. However, there are things you can try.
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How To Dry Plywood
Provided you act quickly, wet plywood can be saved. When plywood gets soaked with water, it usually swells and will eventually rot. However, if your plywood does get wet, there is no need to panic as plywood usually takes at least a few weeks to decay, especially if you live in a cool and dry climate.
How To Dry Plywood Panels
Step 1: Mop Up Excess Water
Since the primary goal is to dry off the plywood, grab a towel or sponge and dry up any puddles of water you see on the plywood.
Plywood is porous, so the plywood will still be wet, but it shouldn’t be dripping water everywhere at this point.
Step 2: Place the Plywood in a Dry Place
The first thing you should do is move the plywood indoors to somewhere dry.
Ideally, you’re placing the plywood somewhere with low humidity, and if possible allowing the plywood to sit in direct sunlight. Anything you can do to help the plywood dry is beneficial.
Step 3: Elevate the Plywood
Don’t just lay the plywood flat on the ground. That will trap water between the plywood and the floor.
Instead, place the plywood on some 2x4s, books, or whatever else can get it off the ground while allowing air to circulate underneath it. I used cardboard boxes in the picture above.
The more air circulation the plywood has, the faster it’ll dry.
Step 4: Improve the Room Conditions
If you’ve placed the plywood indoors, increasing the temperature of the room and decreasing the humidity will help the plywood dry faster.
A dehumidifier or space heater goes a long way toward saving your plywood!
Step 5: Wait
Plywood generally takes a few days to dry, and the thicker the plywood, the longer it’ll take.
For loose 3/4″ plywood boards that are well-ventilated, I usually wait 48 hours before using the plywood (or acting to remove the warp.)
1/4″ plywood usually only requires 24 hours, but it never hurts to let it dry longer!
Step 5: Remove Any Warp
Moisture and water is the primary reason plywood warps, so if your plywood has gotten wet, it’s likely that it’s warped as well.
Wait until the plywood is dry, then tackle the warp. One problem at a time!
I have a whole post on removing warp from wood, where I tested a bunch of different methods to see what worked best.
Tips To Speed Up The Drying Process
- Allow loose panels of plywood to dry out in direct sunlight. Turn these panels around every so often, so each side is exposed to the sun. This can also help to reduce warp.
- Increase the ventilation as much as possible. If there are ceiling fans, turn them on. If you have portable fans, run them in the room.
- Turning the heat up will also help the plywood dry faster.
- If you have a dehumidifier, that’s a good idea as well. Not only will the lower humidity help dry the plywood, but it’ll also reduce warp. Warp is likely to happen regardless (that’s a result of water hitting the wood,) but the dehumidifier will help minimize the amount.
How Long Will It Take For Water To Damage Plywood
The time it takes for plywood to be damaged and unsavable depends on a few factors.
Plywood that was not pressure treated is likely to rot within six months if it has been sitting in water in a hot and humid climate. If the plywood is sitting on the ground or placed near the ground, it will likely rot quickly.
Untreated plywood that is constantly exposed to water from leaking pipes or appliances, rainfall, or sprinklers is likely to rot within one to three years, particularly if you live in a hot and humid area.
If you live in an area with a climate that is cooler and less humid, plywood will take longer to rot.