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Why you shouldn't use a box spring with a foam mattress

Decided to ditch your old spring mattress for a foam one? You probably need to ditch your box spring.

Mercey Livingston CNET Contributor
Mercey Livingston is a health and wellness writer and certified Integrative Nutrition Health Coach. She's written about fitness and wellness for Well+Good, Women's Health, Business Insider, and Prevention.com among others. When not writing, she enjoys reading and trying out workout classes all over New York City.
Mercey Livingston
3 min read
the best frame for foam mattresses

If you have a new foam mattress you might have to buy a new bed frame to support it. 

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Decided to try one of the popular online mattress brands in lieu of a traditional spring mattress? Chances are that you now have a foam mattress which, in case you didn't know, needs a different kind of platform than your typical spring mattress. In fact, most popular online foam mattress brands (like Purple and Casper) recommend that if you have a box spring supporting your older innerspring mattress, you shouldn't use it at all with your new foam mattress.

Read more: Where to try online mattresses IRL | The best air mattresses for 2019  

In fact, using a box spring or other foundation for your mattress that is not recommended by the manufacturer can often void your warranty, depending on the brand. Either way, choosing the right kind of support for your mattress is important for optimal support, comfort, and durability.

Oftentimes, if you buy a foam mattress from an online brand like Casper or Purple, you can buy a bed foundation from the company that's made specifically to support your new mattress. But if the mattress company you buy from doesn't offer one (or maybe you don't want the extra cost) there are a few options for setting up your new bed without having to get rid of your entire old bed setup.

Read more: How to buy a mattress online

What type of platforms work with foam mattresses?

Most companies that make foam mattresses will tell you that a flat, solid surface is the best way to support their mattress. That gives you a few bed platform options to use:


A platform bed foundation is one option for a foam mattress.

Nectar Sleep

Platform bed

A platform bed has a flat, even surface and internal supports that will support your foam mattress.

Slat foundation

A metal or wood slat bed foundation usually works well for a foam mattress since the slats are evenly spaced and provide solid support for the mattress's weight. Check the mattress company's website to see what kind of slat foundation they recommend.


Usually mattress manufacturers sell platforms that support their mattresses. 


Mattress foundations

These are the foundations typically sold by each mattress manufacturer, designed specifically for the mattress.

Adjustable bed

Nectar is one brand that makes an adjustable bed frame that lets you adjust the bed up and down for optimal comfort. The frame is designed specifically for foam mattresses. 

Using a box spring for a foam mattress

So why exactly can't you use your old box spring? According to Casper, the slats on older box springs are too far apart to support the weight of a foam mattress, and that lack of support can cause it to sag. Instead, you need a platform with slats that are much closer together.


Casper's redesigned box spring, "The Foundation."


Casper sells The Foundation, a redesigned box spring that's made to sit on a normal bed frame. It has slats that are closer together to support the Casper mattress. 

Some other mattress companies, like Nectar, suggest that you actually can use your existing box spring to support a foam mattress, as long as it is supported by a metal bed frame, like this

Another important thing to keep in mind is that most companies will encourage you to buy their brand-specific product to support the mattress, which of course, is advantageous for their bottom line. 

Even if you'd rather skip buying another product, it may be worth considering getting a new platform because of the warranty issue. To be safe, check the warranty on your new mattress and verify with the company that the platform you decide to use will not void the manufacturer's warranty.

Buying a new foundation from your mattress company isn't the only way to support your new mattress. You can also create a flat surface with a bunkie board or a piece of plywood. Nectar has step-by-step instructions on how to do that.

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The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.