Polyurethane Foam or Memory Foam for a Murphy Bed?

What the question means

On a mattress listing for a Murphy bed, the words polyurethane foam and memory foam name two different foam materials. They are related: memory foam is a type of polyurethane foam with added compounds that change how the foam responds to pressure. The two are not competitors so much as layers that work together.

The practical question for a Murphy bed is which layer does what, and how density changes support. A mattress that folds into a cabinet must hold its shape when stored upright. Wilding Wallbeds describes its Murphy bed mattresses as specially engineered to stand on-end with no slumping or sagging.

What polyurethane foam is

Polyurethane foam, sometimes called polyfoam or support foam, is the common foam used in mattress cores. It is a flexible foam that compresses under weight and springs back quickly when the weight is removed. In a mattress listing, a foam core is the supportive base beneath the comfort layers.

On Wilding Wallbeds' mattress page, several mattresses list a foam core as the main support layer. The Sunset Sleep Products model with an 11-inch height lists a 7-inch foam core beneath gel memory foam and memory foam layers. The Serta iComfort options list a 7-inch SertaFoam core beneath layers of comfort foam and memory foam.

What memory foam is

Memory foam is a type of polyurethane foam with viscosity modifiers that slow its recovery. It conforms to the shape of the sleeper and returns to its original shape gradually rather than rebounding instantly. This is why memory foam appears as the top comfort layer on many mattresses.

The mattress listings from Wilding Wallbeds show memory foam as a named layer: HexCloud gel memory foam, CradleGel memory foam, and EverCool Fuze gel memory foam are a few of the stated materials. Night and Day Furniture offers a trifold gel memory foam mattress for its cabinet beds. For a separate comparison, see the latex versus memory foam article.

Density and what it means for support

Density is the amount of foam material in a given volume. A higher density foam has more material packed into the same space, which makes it firmer and more resistant to compression. A lower density foam is softer and compresses more easily under the same weight.

Density is not the same as firmness. Firmness describes how soft or hard a surface feels; density describes how much material is there. Two foams can feel similar in firmness while having different densities. A mattress listing may state the construction layers without stating a density number.

For a Murphy bed, the mattress stands on end when stored, so the support layers need enough density to hold their shape. The makers' listings emphasize foam core construction for that reason. Compare the stated construction layers on each mattress listing. The density and support article goes deeper into this relationship.

What a Murphy bed mattress needs

A Murphy bed mattress must do two things: support the sleeper when the bed is down, and keep its shape when the bed is folded upright. Wilding Wallbeds states that its Murphy bed mattresses are specially engineered to stand on-end with no slumping or sagging. The cabinet bed page notes that each model comes with a tri-fold mattress designed to store inside the cabinet.

A common construction is a dense polyurethane foam core for structure with a memory foam layer on top for comfort. The Wilding Wallbeds mattress page shows this pattern: a supportive foam core beneath layers of gel memory foam. A mattress with that construction belongs in a Murphy bed because the core carries the weight of the foam when the mattress is stored upright. If you are shopping for a cabinet bed with the mattress included, the cabinet beds guide lists the options.

What the listings actually state

Listings state the mattress construction in different ways. Wilding Wallbeds lists the layers by name and height, such as a 7-inch foam core with 1 inch of gel memory foam and 1.5 inches of memory foam on top. Night and Day Furniture names the mattress type, such as trifold gel memory foam, without breaking down every layer.

When comparing two mattresses, read what each listing names as the support layer and the comfort layer. A mattress that states a foam core is designed to stand on-end. A mattress that only names a memory foam layer may be softer and better suited as a comfort layer within a core construction. For more on what a listing does and does not say, see the Murphy bed mattress compatibility article.

Which to choose

For a Murphy bed, choose a mattress that states a foam core construction. The core is the polyurethane support layer that holds the mattress shape when it is stored upright. Add a memory foam top layer for comfort. A memory foam top layer conforms to the sleeper, while the core beneath maintains structure.

Density matters in both cases. A higher density core is more resistant to compression and holds its shape better when standing on end. A higher density memory foam layer is firmer in feel and conforms more slowly. Look for density words in the listing and compare the construction layers.

The mattress height also matters for the cabinet. Murphy bed cabinets are sized for a stated mattress height; for cabinet beds, Wilding Wallbeds includes a 6-inch tri-fold mattress. Read the mattress thickness article before choosing a separate mattress, and match the height to the bed's stated cabinet depth.

What to pick for your situation

Questions

Is memory foam the same as polyurethane foam?

Memory foam is a type of polyurethane foam with added compounds that slow its recovery. Standard polyurethane foam springs back quickly; memory foam conforms to pressure and returns gradually.

Why do Murphy bed mattresses use memory foam?

Memory foam is used as a comfort layer because it conforms to the sleeper. It sits on top of a foam core that provides the structure the mattress needs to stand on-end in the cabinet.

What does density mean in a mattress listing?

Density describes how much foam material is in a given volume. A higher density foam has more material and is more resistant to compression. The maker may state the layer heights but not a density number.

Can I use any polyurethane mattress in a Murphy bed?

A standard polyurethane mattress may not hold its shape when stored upright. Look for a mattress that states a foam core construction and a height that matches the cabinet's stated capacity. Follow the maker's mattress guidance.

Do cabinet beds come with a foam mattress?

Many cabinet beds include a tri-fold mattress. Wilding Wallbeds states that its Murphy cabinet beds come with a 6-inch tri-fold mattress, and Night and Day Furniture offers a trifold gel memory foam mattress for its cabinet collection.

Which foam is firmer, polyurethane or memory foam?

Standard polyurethane foam responds quickly and is usually the firmer support layer. Memory foam is softer at the surface and conforms to pressure. Firmness also depends on density, so compare the stated layers of each mattress.