Do You Need a Box Spring or a Foundation?
After carefully choosing between an innerspring, latex or memory foam mattress, settling on a mattress comfort level that matches your sleep style, quizzing friends about what they sleep on, and reading more reviews than you could ever count sheep, you've finally picked a mattress. And suddenly you're faced with another decision—do you want a box spring to go with that?
“We get a lot of questions from consumers who are wondering whether the box spring is an essential component of the mattress 'system,' as salesmen say, or just a way to sell you more stuff, like rust-proofing for a new car," says Frank Apodaca, of review site thesleepjudge.com. The answer is a little of both.
Box spring vs. foundation
Historically, a box spring was a wood box filled with metal coils that added springy flexibility and cushioning to the thin, stiff mattresses of the day. But box springs haven't actually contained springs for about 20 years. And though amongst the public the name box spring has stuck, the proper term these days is “foundation."
Foundations can have a fabric-covered or exposed wood frame, with a solid top or one made of wood slats. Although they do add a bit of flex to the bed, their main purpose is to support the mattress and raise your sleeping surface to a comfortable height (a standard box spring is around 9 inches thick).
Alternatively, you can purchase a platform base or adjustable base, both of which support a mattress without need for a separate bed foundation. Some beds also work with a Euro-style slat system that provides adjustable, flexible suspension.
(For a closer look at how an adjustable base works, check out The Definitive Guide to Adjustable Bases.)
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Do you need a box spring?
The short answer is you don't need a foundation, says Keith Cushner, of the sleep health site tuck.com. “Not a single one of our staff members sleeps with a box spring," he says. “Unless you're hiding money inside, there's no purpose to buying one."
Instead of a box spring, a platform or an adjustable base makes a perfectly acceptable support for a mattress. You can even put a mattress directly on the floor and get plenty of support, says Alessandra Woolley, of mattressadvisor.com. But you might not want to: "That can create problems with dust, mold, and allergens," she says.
You need a box spring or foundation if:
- You're using a standard metal bed frame—or any bed that provides only a rim around the perimeter to hold the mattress, perhaps with a few cross pieces of wood. Without a box spring, the mattress won't have adequate support.
- Your bed frame is set at a height that assumes a foundation. In that case, you'll need a box spring to raise your sleeping surface to the optimal height of about 25 inches off the floor. (Low-profile foundations, which measure around 5 or 6 inches, work with especially thick mattresses or higher-than-standard bed frames.)
- Your mattress warranty requires a specific type of box spring. Some latex foam mattresses, for example, specify the allowable spacing of the slats in an open-slat foundation. “If I was spending a lot on a mattress and the company said I should spend another $100 or $200 on a particular box spring, I'd go ahead and pay a little more to protect my investment," says Michael Magnuson, founder of the mattress price-comparison site goodbed.com.
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Box spring and foundation options
Brick-and-mortar retailers and full-service online companies sell and deliver box springs that meet warranty requirements for their mattresses. Bed-in-a-box companies generally offer assemble-it-yourself box springs, or provide lists of compatible box springs you can purchase from local retailers. That adds another step to the buying process, but it's far easier than putting together the foundation yourself, Cushner notes.
You could also keep your existing box spring when you replace the mattress. That's fine, as long as it's only a few years old; is not sagging, squeaking, or otherwise damaged; and your new mattress warranty doesn't require a new foundation. If you are keeping an existing box spring for a new queen or king size mattress, be sure it has adequate center support to prevent sagging.
And whatever you do, don't even think about using your old mattress as a box spring. It's too soft and won't create a stable, comfortable surface for a good night's sleep, the most important feature of any bed.
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Learn more about foundation options in our mattress guide.