How to Fix a Sagging Mattress with Plywood

A sagging mattress can disrupt our sleep and lead to aches, pains, and discomfort. If you’re experiencing this issue, you may be wondering how to restore your mattress’s support and firmness without investing in a new one.

Fortunately, a simple and cost-effective solution exists: using plywood. By placing a sturdy plywood board underneath your sagging mattress, you can provide the additional support it needs to regain its shape and alleviate sagging areas.

How to Fix a Sagging Mattress With Plywood

In this guide, we will delve into the step-by-step process of how to fix a sagging mattress with plywood.

From measuring and cutting the plywood to properly positioning it and ensuring optimal support, we will provide you with all the information you need to successfully implement this method.

Say goodbye to restless nights caused by a sagging mattress and discover the benefits of this practical and accessible solution.

Does Putting Plywood under a Mattress Make It Firmer?

Yes, putting plywood under a mattress can make it firmer. Plywood is solid, rigid material that provides support for the mattress and prevents it from sagging over time.

It also helps prevent the mattress from collapsing in pressure points like the hips and shoulders. By using plywood under your mattress, you can extend its life span and improve overall comfort.

There are several ways to use plywood when fixing a sagging mattress. If your bed frame already has slats or a wooden platform, simply cutting plywood sheets to fit will effectively help to create a firmer sleep surface.

For beds without frames or one with metal links instead of wooden slats, adding a layer of plywood on top of other materials like box springs or a mattress foundation can be beneficial.

Additionally, adding plywood under the mattress in certain areas such as the center or hip area is also an effective way to create more support and firmness for those pressure points.

If you prefer not to use plywood on top of your bed frame, you may want to consider using it as a mattress topper instead of buying an entirely new mattress.

What Is the Best Plywood for Mattress Support?

When it comes to choosing the best plywood for mattress support, look for one that is thick and strong enough to provide stable and consistent support.

Choosing the Best Plywood for Mattress

The most common thicknesses are 1/2” or 3/4” plywood. Make sure the grade of plywood you use is rated for outdoor use since a sagging mattress is usually located in an area with moisture exposure, such as near a window or door opening.

For added comfort, consider using pressure-treated plywood with a smooth finish. This type of wood has been treated with chemicals that make it resistant to rot, termites, and other insects.

It also provides additional protection against humidity changes that can cause warping and cracking over time.

When cutting plywood for mattress support, use the right tools to ensure a precise and secure fit. A circular saw or jigsaw with a fine-toothed blade is best suited for cutting plywood.

Be sure to measure and mark the pieces accurately, as plywood can split or crack if cut too quickly. After cutting, sand and finish the plywood before installing.

10 Methods How to Fix a Sagging Mattress with Plywood

Method 1: Measure the Mattress

Start by measuring the dimensions of your mattress. Use a measuring tape to determine the length and width accurately. This measurement will help you cut the plywood to the appropriate size for a precise fit.

Measuring the Dimensions of Your Mattress

Method 2: Choose the Right Plywood

Select a high-quality plywood board that is sturdy and supportive. Opt for plywood with a thickness of at least ¾ inch to ensure optimal reinforcement. Consider using plywood made from hardwood such as birch or oak for added durability.

Method 3: Cut the Plywood

Using a saw, carefully cut the plywood to match the dimensions of your mattress. Make sure to trim the edges smoothly to prevent any sharp corners or rough edges that could damage the mattress.

Secure the plywood to the mattress using a staple gun or screws. This will help keep the mattress rigid and prevent further sagging.

Method 4: Sand the Edges

To ensure a smooth and safe surface, use sandpaper to sand the edges of the plywood. This step helps to remove any splinters or rough spots that could potentially cause discomfort or damage to the mattress.

Method 5: Position the Plywood

Place the cut plywood board directly underneath the sagging area of the mattress. Ensure that the plywood extends evenly across the entire width of the mattress, providing comprehensive support and preventing further sagging.

Method 6: Secure the Plywood

To keep the plywood in place, consider using adhesive Velcro strips or non-slip rug grippers. Attach these to the corners and edges of the plywood and the mattress, ensuring a secure connection. This prevents the plywood from shifting or sliding during sleep.

Method 7: Add Extra Support

For mattresses with severe sagging, you may require additional support. In such cases, cut multiple pieces of plywood to fit the sagging areas and stack them on top of each other. This layering technique provides enhanced reinforcement and reduces the depth of the sag.

Method 8: Test for Comfort

Lie down on the mattress to test the level of comfort and support provided by the plywood. Adjust the positioning or number of plywood layers if necessary to achieve the desired level of firmness and alleviate sagging.

If the mattress still appears to be too soft, add more plywood layers. Alternatively, if it is too firm, remove some of the plywood layers. Allow a few days for the mattress to adjust and become accustomed to the new plywood support before making further adjustments.

Method 9: Consider a Mattress Topper

To enhance comfort and further minimize the feeling of the plywood beneath the mattress, consider adding a high-quality mattress topper. Opt for a plush memory foam or latex topper that provides an extra layer of cushioning.

Latex Topper That Provides an Extra Layer of Cushioning

Not only will a mattress topper add more plushness and reduce the feeling of the plywood beneath your mattress, it may also provide extra support.

Method 10: Regularly Inspect and Adjust

Periodically inspect the mattress and plywood to ensure they remain in proper condition. Check for any signs of wear or damage and readjust the plywood if necessary.

This will help maintain the optimal level of support and prolong the life of your mattress. Additionally, it is essential to rotate the mattress every few months in order to even out wear and tear. This will also help keep your mattress from sagging over time.

Things to Consider When Fixing a Sagging Mattress with Plywood

1. Choose the Right Plywood:

When fixing a sagging mattress with plywood, it is important to choose the right type of plywood. A softer plywood such as pine or spruce is best for comfort, while a harder plywood like birch or maple will last longer.

A Softer Plywood Such as Pine or Spruce is Best

2. Measure Carefully:

Accurately measuring the area where the plywood will be placed and cutting it to size is key in fixing a sagging mattress with plywood. To ensure a snug fit, measure twice and cut once!

3. Add Support Features:

Adding support features such as wooden slats or cross-braces can help extend the life of your mattress when using plywood to fix it. Such additions can also provide more stability for your bed frame, making your sleeping experience even better!

4. Consider the Thickness of Plywood:

The thickness of plywood used to fix a sagging mattress should be taken into consideration as well. Too thick a board may be too rigid to provide adequate comfort, while a board that is too thin may not provide enough support.

5. Use Fasteners:

For extra security, use fasteners such as nails or screws to secure the plywood in place on the bed frame. This will prevent any shifting or movement of the plywood and can ensure your mattress lasts longer.

With a few simple tips and tricks, you can fix a sagging mattress with plywood quickly and easily! With the right materials, careful measurements, and some added support features, you can have your bed looking like new in no time.

Just make sure to use proper fasteners for extra security and enjoy a great night’s sleep!


Fixing a sagging mattress can be intimidating, but arming yourself with knowledge and the right materials can help.

After researching and understanding the right size of plywood to use to fit under your mattress, buying the best kind of plywood possible for durability, and following the steps above correctly, you’ll have a makeshift fix that will bring back an extra level of comfort to fibromyalgia flare-ups or other body aches.

The good news is that this project shouldn’t take more than an hour or two and is well worth every cent spent on tools, plywood, padding, and any additional items needed.

So what are you waiting for? Hopefully, this article gave you some helpful tips about how to fix a sagging mattress with plywood successfully, so now that you have the proper knowledge on how to get the job done, why not give it a try today?

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Jennifer Branett

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