Plywood is a staple in my workshop, where I construct many useful jigs and even some pieces of furniture. I was caught in a downpour when bringing some home from the store the other day. Water seeped through and drenched the top three layers of plywood.
With that in mind, I will explain what I did to save those sheets and how. In light of this, one would wonder if plywood is watertight.
Plywood can be submerged in water for brief periods of time, then dried out without losing its structural integrity or aesthetic finish. De-lamination of the softwood layers can occur after prolonged exposure to wet conditions. It is possible for the glue in some plywoods to degrade and come loose.
Keep reading to find out how I managed to keep my plywood sheets from being thrown away. Let’s start with a definition of plywood.
What Is Plywood?
Thin sheets of softwood are layered and glued together in stages, with the grain running in opposite directions between each layer to create plywood. Urea-formaldehyde or polyurethane are common types of glue. Plywood’s alternating layers make it a durable choice as a flooring or furniture top.
Plywood is made by adhering many of these thin sheets together to create panels of varying thicknesses. The most common thicknesses of plywood are 6, 9, 12, 17, 19, 25, and 33 mm.
If you want to know whether or not MDF may be used outdoors, read the rest of my detailed essay. It could catch you off guard.
Does Rain Ruin Plywood?
Plywood is not vulnerable to water damage from light rain. If the rain or storm merely lasts for an hour or so, the plywood shouldn’t be damaged.
But plywood should not be left out in the rain overnight. This will cause water to seep through the layers of wood, potentially weakening the structure.
Keep in mind that plywood is just layers of softwood cemented together. The wood fibers aren’t watertight, but the glue is.
Plywood that has been left out in the rain for a lengthy period of time may swell, warp, and possibly separate at the seams. The glue is water-resistant, however it can be compromised by heavy rain.
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3:42 PM · Jan 21, 2017
Does Plywood Absorb Water?
Since plywood is made from layers of softwood fibers that have been bonded together, it does absorb water. Like other types of wood, the cell walls of these softwood layers can absorb water.
Water will soak through the layers of wood, but it may take several hours for this to happen.
Plywood is typically sold in bundles, making it more cumbersome to move it in one go. Check out my write-up where I detail the plywood bundle count.
The rate of water absorption can also be affected by the type of plywood used. Instead of using an inexpensive piece of OSB, you should use A-grade plywood that has been carefully pressed. Hardwood layers add strength to some plywoods and make it more resistant to water damage since its cells are less porous.
Plywood is water-resistant to a certain extent.
Can Wet Plywood Be Saved?
Even if your plywood has been submerged in water or exposed to moisture for several hours, there is still hope for it. Where the water has begun to seep in, the edges may have turned a dark discoloration.
The key is to keep it dry by removing any extra water right immediately and keeping it covered. After that is complete, we may talk about how to dry it out.
Witness my techniques for repairing warped plywood and learn if perfectly flat sheets are even available.
How Do I Dry My Plywood?
In this article, I will explain how to thoroughly dry off your plywood. The plywood I made using this method turned out beautifully. Let’s get that water out and let it evaporate.
Put the plywood in an indoor, dry area to prevent it from getting wet. Keeping it outside (even under cover) is not ideal, particularly in humid climates. The wood fibers are constantly taking in and giving off moisture. It’s best if you can find the driest spot you can.
First, you should get rid of any extra moisture by any means necessary. The water can be soaked up by using a few dry cloths or a layer of dry sawdust.
Sheets should be stacked individually on packers or bearers of timber. The goal here is to provide equal air circulation on both sides of the sheets. If you want your sheet to stay flat and not droop, I recommend using a bearer or packer every 300mm or foot.
Make use of a fan by positioning a few strong fans so they blow over the sheets, which will cause the air to travel rapidly, removing any moisture. Those packers are useful because they allow air to circulate around the board.
Make use of heat, preferably in the form of a heater or a heater with a built-in fan if at all possible. To increase the temperature in the room. Plywood sheets may distort or cup if heat is applied directly to them.
I recommend leaving your linens like this for a few of days to ensure they dry completely. This could take a little longer if you’re in an area that typically sees a lot of rain and storms at this time of year.
After you’ve finished the above processes, your plywood should be dry and ready for use.
How Long Does Wet Plywood Take To Dry?
It takes about four to five days for wet plywood to dry out if it is placed on packers and the air can circulate freely around the entire sheet.
It could take a couple of weeks for plywood to dry out if you’re not using a fan or heater.
Listed below are some alternate techniques for slicing plywood.
Are Your Plywood Sheets Ruined?
Maybe you’ve dried your plywood as much as you can; if so, how can I tell whether it’s completely ruined?
Any wooden objects that have been exposed to too much water may end up with dark stains all over the sheets. It may just be a matter of discolouration, but this shouldn’t have any effect on the quality of your plywood.
Discoloration is a surface flaw that requires a lot of sanding to remove. It may not be possible to sand it out in some instances. This can be a hassle if you bought high-quality plywood and planned to stain and seal it.
It’s possible that your plywood will be ruined in this situation, forcing you to use it for less important repairs.
Next, check for warping or cupping. Plywood that has absorbed a lot of water will likely be severely warped or cupped. If you want to check if this is a problem, just look along the surface.
It’s possible that, if you plan to divide the sheet into smaller pieces, you’ll be able to remove much of this.
Plywood is difficult to inspect for damage until the edges begin to expand or de-laminate. Discoloration will be most noticeable around the edges.
De-lamination usually only affects the very edge, so you should be able to trim off that small portion before utilizing the sheet.
Plywood that feels spongy all the way through when pressed has de-laminated and should be thrown away.
What Kind Of Plywood Is Waterproof?
Unless you’re working on an outdoor project, you won’t ever need waterproof plywood indoors.
For the most watertight and durable plywood, go no farther than marine grade plywood, often known as marine ply. Hardwood layers replace softer wood ones in this plywood, making it more resistant to moisture.
Marine Ply is waterproof because it is bonded with waterproof glue, but its increased resistance to water comes from both the hardwood and the glue. Depending on the conditions of use and location, some types of Marine plywood come with a 15- to 25-year warranty.
But don’t assume it’s completely waterproof. It’s better able to withstand water. It’s held together with waterproof adhesive, but drowning it will eventually kill it.
Because it is not chemically treated, marine ply is susceptible to rot.
What Works Best For Plywood Finish
If you’re using plywood for an outside project, it’s important to protect it so it lasts for many more years. How I get a solid finish and airtight seal on plywood:
Sand – If the plywood you bought is of high quality, you can begin smoothing out the irregularities with 120 grit sandpaper. Get the edges as smooth as you can by paying great attention to them. Use sandpaper with a grit between 180 and 240 if you’re sealing plywood for an indoor piece of furniture.
Dust off the plywood by wiping it down with a lint-free cloth.
To paint or to seal in clear? – I think this essay would be of great help if you are just going to paint the plywood. Keep going for a neat conclusion.
Use a sanding sealer to protect the plywood and lay a solid base for your topcoats, which will help you get the best possible finish.
More Sanding – Always sand after using sanding sealer. You can get the plywood surface perfectly smooth and ready for a finish coat by using sandpaper with a 240 grit.
Top coat – Use whichever polyurethane finish you like now. For expansive areas, a roller is your best bet. Potentially more than one coat needs to be applied.
Can Plywood Get Wet During Construction?
Plywood is widely utilized in construction because it can serve as either wall bracing or flooring in multi-story homes.
Can plywood get wet during construction? This plywood will likely get rained on before the roof is on.
Plywood used for framing or structural purposes can get wet without weakening because of its A-grade glue bond. It can resist a good deal of dampness before showing any signs of wear.
Plywood that gets wet won’t be a huge problem because there are usually plenty of sunny days to dry it out. However, if the plywood edges begin to delaminate during prolonged periods of rain, you may have a problem.
Is finding a new method to rip your plywood sheets a priority for you? Additionally, these five methods are applicable.
Conclusion
The answer to the question “what is plywood?” has been found, and you can safely use your plywood with a moderate amount of water in most situations. But if your plywood has been sitting in the rain for a few days, its usefulness is highly unlikely.
If you wanted to learn more about what happens when plywood gets wet, I hope you found this information helpful.
