How to Fix a Sagging Mattress: Top Ideas on How to Save Your Old Mattress

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Written by: Alex Savy
Read 15 minLast updated on March 14, 2023

When your old, loyal mattress starts wearing off, you begin feeling less comfortable during sleep.

However, you can still save your restful slumber.

There are different ways to fix a sagging mattress, and we are going to look at all of them today to help you find the most effective solution. So, without further ado, let’s dive right in!

Key Takeaways

  • In most cases, flipping or adding a support pad should be enough to make a sagging mattress feel more comfortable. However, we have noticed that mattresses older than 10 years are hard to fix. In this case, it’s better to buy a new one.
  • Adding a layer of plywood underneath the mattress is one of the fastest and cheapest ways to make it feel slightly firmer and a bit more supportive. We also added a layer of fabric between the wood and the mattress to avoid damaging it further (as plywood may splinter and rip the cover).

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How to Fix a Sagging Memory Foam Mattress

How to Fix a Sagging Mattress: Top Ideas

While most top-rated memory foam mattresses typically last for up to 10 years, some models (and cheaper options) may develop sags sooner than that. In this case, here’s what you can try to do:

  • rotate your mattress (180 degrees) to start applying pressure to different areas of the mattress and to minimize the sags. I rotate mine every 4 months, which is when I usually start seeing slight body indentations on the surface of the mattress. Rotating it allows me to redistribute the pressure and keep the surface even and comfortable;
    Rotating the mattress
    Rotating the mattress
  • if your mattress allows for it, flip it and sleep on the other side that doesn’t have any sags yet;
  • put your mattress on the floor to give it firm support and, potentially, help it even out its surface to at least some extent. Most mattresses can be used on the floor safely, but you might want to add a layer of insulation (a blanket, for example);
  • get a mattress topper (make sure you pick a dense, firm enough model that could change the feel of your saggy mattress and offer some support for your spine);
  • buy an under-mattress support pad (or a couple of them) and put it under the spots where the sags are the most noticeable. You can also get a full-size under-mattress pad that can cover the whole perimeter of the bottom of your mattress;
  • change the layers. Some memory foam mattresses allow users to remove certain layers from the construction and buy new ones instead. In many cases, changing the top layer of a memory foam mattress is enough to battle sagging. However, I prefer changing the middle layer as well. It makes my mattress more supportive, allowing it to keep my spine properly aligned during sleep. Plus, I am a fan of firmer mattresses, and changing the middle layer as well helps me keep my mattress sturdy;
  • adjust the slats. Often, memory foam mattresses develop sags in those spots where the slats are placed too far from each other. So, if your foundation allows for it, detach the slats and move them closer to each other to create more support for your mattress.

How to Fix a Sagging Pillow-Top Mattress

Even some of the best pillow-top mattresses can’t serve you forever. And when the time comes, you might want to prolong the lifespan of your mattress and try a few tricks to combat sagging.

Now, in pillow-top mattresses, the first layer to become weaker is usually the top one. Some become flat; other models can develop dents and body impressions. Whatever the case is, you can save the day with the help of a good mattress topper. You see, if your old pillow-top mattress still has a rather supportive core but lacks that cushioning on top, you can add a quality topper for added comfort.

You can also rotate the mattress. This way, you will sleep in a new spot on your mattress, and not on the old indentations. Keep in mind that flipping is not an option for pillow-top mattresses. Their construction does not allow for that.

If the proper support is the main issue, you might want to give your mattress a little boost. Getting a new foundation often works, especially if the old one has developed weak spots with time. You can also try adding a layer of plywood between your pillow-top mattress and the foundation. Chances are, it will create solid support for the mattress. Speaking of which…

How to Fix a Sagging Mattress with Plywood

Using plywood seems like a very popular (and a cheap) way to fix a sagging mattress. However, it might not work for everyone.

Yes, a layer of plywood can help your mattress feel slightly firmer or a bit more supportive. If your old mattress has small(ish) dents, adding some plywood can potentially make it feel more even. It’s also a great option if your foundation is weak, or your mattress is standing on slats that are too far apart.

All things considered, plywood can save a mattress if it’s not too old. However, if yours has deep dents or feels super saggy (because it’s super old), plywood might not work in this case. Some users add two layers of plywood to make sure the base for their mattress remains sturdy, but that doesn’t always help either. 

The good news is, plywood is quite cheap, so if you try this method and it doesn’t work, you won’t lose that much. Just don’t expect it to be a miraculous solution to your mattress-related problems, especially if your mattress is older than 7-8 years, which is an average lifespan for many mattress types (1).

Others Methods You Should Try

I get it:

A new mattress is a serious investment. No wonder you want to save your old one and keep using it longer. After all, you’ve probably paid a lot for it.

if your mattress has become saggy

The good news is, there are a few tricks you might want to try if your mattress has become saggy. Aside from flipping or rotating the mattress, using a topper, and adding plywood under the mattress, here are a few more examples of what you can do:

Check the warranty coverage

Many mattress companies offer warranties that cover premature sagging and body indentations. So, it wouldn’t hurt to read about your mattress coverage carefully. Who knows, maybe the company will offer to repair or even exchange your mattress.

Get a new foundation

Even long-lasting mattresses can lose their supportive properties when standing on an unreliable base. If you notice sags in your mattress, check the foundation – chances are it’s broken in some spots. In this case, getting a new base for your mattress can alter the way it feels and might help it get back to its normal state.

Switching a bed frame
Switching a bed frame

Use extra pillows

Sometimes, a few pillows are enough to balance out the sags in your mattress. You can simply cover the gaps using extra pillows to increase your comfort (however, remember that it’s just a temporary measure). Some users also put pillows under the mattress to kind of push the dents out and to create a more even sleeping surface. 

Add a box spring

If you are using a bed frame that does not require a box spring, the latter might come in handy as a nice addition to the overall support structure. You see, a new box spring can create a more reliable base for your mattress, especially if the foundation is old.

Get a new mattress

Some users consider it as the last resort, others choose to get a new mattress because it’s the easiest (and the most effective) solution. Here’s the good news: there are plenty of great mattresses that don’t sag, which means your new investment will certainly be a long-term one. You might also want to check some of the best mattresses according to Reddit users that won’t be likely to disappoint you even with time.

Things to Do to Prevent the Mattress from Sagging

Fixing a sagging mattress shouldn’t be too hard in most cases, but preventing sagging is an even easier solution. And luckily, there are several things you can try to achieve that:

Flip and Rotate the Mattress Regularly

Flipping and rotating the mattress can help distribute the pressure evenly. In other words, the mattress will experience a more even wear and tear process when the sleeper rotates and flips it from time to time. Naturally, this will reduce the chances of sags appearing.

Usually, it’s enough to rotate the mattress every 3-6 months. As for flipping, it can be done every 6-12 months.  

Change the Way You Sleep

Another way to redistribute the pressure is by sleeping in different spots. For example, if you sleep alone, you can alternate between the two sides of the mattress. If you share the bed with your partner and there’s a weight difference between you two, it’s a good idea to switch sides from time to time.

Make Sure the Mattress Is Properly Supported

Sagging can occur when the mattress doesn’t receive uniform support (for instance, when the foundation is old and wobbly). Thus, keeping the mattress on a box spring or a suitable foundation can significantly reduce the chances of sagging. Slats can work too, but they have to be spaced accordingly (3 inches for memory foam mattresses).

Invest In a Durable Mattress

Some people choose to get a new mattress after dealing with a saggy one. And that’s often the best thing they can do for their back health, as sleeping on a saggy mattress often leads to pain and issues with the spine.

Here’s the deal, though: getting an extra-durable mattress can help you forget about sagging for many years. Thus, it’s better to do your research and choose a mattress that uses extra-durable materials and comes with an extended warranty

My Experience with Fixing a Sagging Mattress

Trust me when I say this:

I have tried every possible solution to fix my old memory foam mattress. After all, experimentation is an excellent way to discover more ways to fix something that doesn’t work anymore. 

Adding a sheet of plywood under the mattress had the best results for me. That being said, I also tried placing the plywood on top of the mattress and under my thick memory foam topper. This configuration helped me get the extra support my old mattress lacked. At the same time, the foam topper cradled my pressure points, so I didn’t press into the plywood and, thus, didn’t experience any pain.

Of course, this solution was only temporary. Under the topper and the plywood, my mattress kept giving in and was losing its supportive properties daily. But if you need your mattress to hold on for a couple of weeks until you buy a new one, placing a plywood sheet under the topper might be a good solution.


What causes mattresses to sag?

Sagging is the result of normal wear and tear that happens after some time. It happens because mattress materials tend to lose their properties with time, especially because they always experience pressure from the sleeper’s body.

Can a saggy mattress affect my sleep?

Yes. An old, saggy mattress cannot provide proper support. As a result, it can’t keep your spine in a neutral alignment. This can lead to discomfort (and thus, poorer sleep) and even more serious issues (like back pain).

How long should a mattress last before sagging?

It would depend on the type of the mattress, but generally, mattresses last for around 7 to 10 years before they start sagging.

Can you flip a pillow top mattress to make it firmer?

No, you can’t flip a pillow-top mattress to make it feel firmer. Such mattresses are designed to be used on one side only. However, you can rotate your mattress 180 degrees to change the feel of your sleeping surface.

Can a sagging mattress cause back pain?

Yes. A saggy mattress can’t keep your spine supported during the night, which can lead to pressure build-up in certain parts of your back and, consequently, pain.

Wrapping Up

As you can see, a saggy mattress can still “guard” your restful sleep if you help it a little.

Whether you decide to add a mattress topper, use plywood, get a new foundation, or prop the mattress with pillows, remember: these are usually temporary solutions. So, pay attention to how your body feels. If you start experiencing back pain or frequent nighttime awakenings due to discomfort, perhaps getting a new mattress might be the best idea.

How long have you been using your current mattress? And what anti-sagging methods have you already tried? Let us know in the comments!


  1. Living Spaces Shopping Basics (n.d.). How Often Should I Replace My Mattress? Retrieved from 

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