How Do You Store Plywood So it Doesn’t Warp? Solved!

Often when you buy plywood at a DIY store, it is stored standing upright which then has a tendency to make it warp or bend. Plywood will also warp when in damp conditions. Plywood should always be stored flat and in dry conditions to prevent warping.

When you are storing plywood, it’s important to make sure that it isn’t exposed to moisture. Doing this can lead to the wood warping and any leftover boards you have will be rendered pretty much useless.

But there are ways of storing it to make sure that it stays in the best condition ready for your next project. In this guide, we’ll be telling you everything you need to know about the correct storage of plywood and what to do if you’ve found your boards are warped.

What Is Plywood?

Plywood may be a modern construction material but it’s actually been around for more than 200 years with the concept first having been thought up back in 1797! It was a guy named Samuel Bentham who initially came up with the idea as a way of creating veneers and his patent has now evolved to become the type of plywood we use today.

Essentially plywood is a material that is made up of layers of wood that are glued together. Plywood is very strong thanks to a manufacturing process known as cross-graining. As each layer of wood is applied, it is rotated by 90 degrees which gives the board greater strength and durability in all directions. This is likely why it is such a popular building material.

So, what exactly is plywood used for? Well since it is so strong its primary use is within construction for structural purposes. The reason for this is that while it is relatively lightweight, plywood is able to withstand an enormous amount of stress. Moreover, it has excellent weather resistance so is ideal for outdoor purposes.

That said, in the construction industry, there are different types of plywood designed for indoor and outdoor use respectively. The exterior type of plywood (often referred to as marine ply) is made using water-resistant glue so it is much more easily able to stand up to the elements.

Plywood is also a very common material inside buildings for things such as kitchen cabinets, cladding and general furniture making. It’s certainly one of the most versatile materials out there and many DIY enthusiasts choose it for their projects as well as professionals using it for commercial purposes.

Why Does Plywood Warp?

If you want to successfully store your plywood and avoid warping then it helps to understand exactly why this happens. It’s a pretty simple science and involves exposure to moisture.

Think about wood in its natural state; over time, especially without treatments, it will deteriorate if it gets wet as the wood grain swells unevenly. When you store plywood boards in a humid or moist environment, the layers of wood absorb this moisture and swell. As the wood dries out again, those swollen parts shrink again but it is extremely unlikely that they would ever shrink back to their original shape. Instead, they warp and bend.

You can see which parts of the wood absorbed the most moisture just by looking at how the board bends. The convex side would have absorbed a lot more and this is why it has changed shape.

Sheet materials are also prone to warping when stored in a vertical or upright fashion. Gravity then takes its toll on the wood, if it is not supported sufficiently and then it begins to sag from the middle.

Store Plywood So It Doesn’t Warp

The key to storing plywood is to make sure that it is kept in a dry environment and stored or stacked horizontally and well-supported across the length and width of each board. As we have already learned, failing to do this is the leading cause of the wood warping. The problem is that many people opt to store their leftover wood in a garage or workshop purely because of how practical it is. After all, nobody wants a stack of boards stored in the house!

Moreover, you have to be careful that, when storing plywood, you don’t place the boards close together. This prevents sufficient air from being able to flow between the boards which go a long way in keeping them dry.

Many experts use plywood separators which allow you to store sheets of plywood with adequate space between them. You can easily make these spacers at home using the following steps:

1. Take some leather or heavy cloth and cut this into two one inch wide strips.
2. Now take some wooden blocks measuring 2” x ¾” x 1” and screw these along the strap leaving at least an inch gap between each block.
3. You can then place the blocks between boards to allow space for air to flow.

Using this method is incredibly effective and will allow you to store your plywood boards for as long as you need. However, you should keep in mind that the boards still need to be kept in as dry an environment as possible. Allowing good ventilation in the room itself will help.

Can You Salvage Warped Plywood?

If you have stored your plywood boards for some time only to come back and find that they have warped then it is frustrating. That said, there may still be a glimmer of hope and there are a few ways that you might be able to undo the warping that has already occurred. Do keep in mind that this won’t work in all cases, especially where the boards have warped by an extreme amount.

Use Weights

If you are looking for a very easy to follow technique to restore warped plywood then using heavy weights is as simple as it gets. There aren’t many steps involved and in most cases, you’ll find the results to be pretty decent.

You’ll need to find a flat surface on which to lay the plywood and find some heavyweights. The dumbbells you use for working out would be ideal for this, or indeed some heavy power tools can help at short notice. Once you have your wood on a flat surface simply place the weights evenly over it. Be careful not to place them so close to the edges that it causes them to bend.

You will need to leave the set up overnight if you want the best results but sometimes, if the wood is very warped, you may need to leave it a little longer. There have been some examples of this method where people have had to repeat the process for up to a week so don’t worry if this happens. Of course, the heavier the weights you use, the more effective they will be.

There have been some stories of people that will simply place a warped piece of plywood at the bottom of a stack and allow the weight of the others to flatten it. The problem with this, however, is that you don’t get the airflow we discussed earlier so it’s much easier for moisture to build up. Unless you’ve got a totally arid environment in which to store the wood, we wouldn’t suggest using other boards to flatten a warped one.

Use The Sun

For those of you who want to make the most of what nature has to offer, it is possible to use the heat from the sun to get your warped plywood back into good shape.

This works by spraying a good amount of hot water on the concave part of the plywood; the bit that didn’t get as wet initially. You will then need to lay the plywood board down on a flat area that will have full sun for a good part of the day. Something like a lawn or driveway is ideal, provided there are no lumps or bumps. Ensure that you place the board down with the hump facing up.

You can also place a heavy item onto the hump as this will help the flattening process along. It would be difficult to say just how long you’ll need to leave the board in place for this to work as each case is different. Just keep checking the board and remove everything once it has successfully flattened out. That said, it’s important not to leave it for too long as the heat and light from the sun could damage the wood if it is overexposed. So make regular checks.

It goes without saying that the warmer the sun, the better this method will work. If you live in a cooler climate or it’s winter then you might have a little more trouble using this method. But if there’s plenty of sun, you will find that this is quite an effective way to get the job done. You’re never going to get 100% perfect results this way but it’ll certainly be more than enough to be able to use the board afterwards.

Clamp The Plywood

Using clamps is very similar to the heavyweight method we discussed earlier as it relies on applying pressure to the warped areas of the wood. This is also an excellent choice if you don’t have any weights because let’s face it, as woodworkers, we’ve all got various types of clamps lying around.

Again, you’re going to need a flat surface on which to place your wood; the flatter, the better. You then simply need to take your clamps and use them to clamp the wood to the surface in as many places as you need. This will cause the board to flatten.

You may find that you have trouble getting some of the clamps to reach parts of the board, depending on its size but popping something like a can of paint on the top will give that bit of added pressure.

Much like the heavyweight method, you’re going to need to leave the boards overnight for the best results. Again, if you haven’t had full success after the first night, you can repeat the process as many times as you need.

Conclusion

There is nothing more annoying than coming to get a piece of plywood board only to find that it has warped while in storage. This usually happens because of exposure to moisture and poor air circulation or storing the boards in a vertical rather than horizontal position. The best way to avoid warping is to make sure that you store your plywood in a dry, well-ventilated room and horizontally on a flat surface.

Using plywood spacers is the best way to store plywood regardless of the environment as this ensures good airflow between the boards. However, if you do have problems, there are a few ways you can restore warped plywood using things you’ll already have at home.