What Is a Matching Foundation on a Bed?

Box Springs

• Although some use the terms "foundation" and "box spring" interchangeably, a box spring is one type of mattress foundation. It consists of a wooden frame that is filled with large metal coils. The combination of the frame and the coils gives your mattress firmness and softness at the same time, while also holding your mattress on your bed frame and up at a comfortable level for getting into and out of your bed.

Posture Box

• A posture box is a simple, inexpensive foundation. It is typically a wooden box that has been covered with fabric to match the mattress. Posture boxes are the least expensive foundation option, and also the least durable. They do not have springs and so do not provide any bounce or flex.

Modular Foundations

• Modular foundations, sometimes called flex grid foundations or modular grid foundations, have wooden frames that are filled with coils and also feature a grid of metal wires for additional flex and support.

To Buy or Not to Buy

• While mattress dealers and furniture stores will likely encourage you to buy a matching foundation in addition to your new mattress, you might wonder if it is really necessary. After all, if you skip the foundation, you'll save a nice chunk of money. If you have a platform bed, a foundation is unnecessary. However, if you have a standard bed frame, you'll need a foundation as well as a mattress. While your new mattress may work just fine with your old foundation, the manufacturer will often negate the mattresses' warranty if you place it on an old or mismatched foundation. Additionally, mattress manufacturers pair mattresses and foundations for optimal comfort and performance.