Extra firm topper on top of plywood - works great! Density question

[phoenix]

Hi kjohnson,

Thanks. You have the concept correct. I am putting an extra firm topper on top of a plywood twin-size board. These are just two that I’m considering;

Thanks for the clarification. I appreciate it.

The 3" topper: 3-inches thick, extra firm conventional foam
100 percent urethane foam;
Provides 1-4/9 pounds density per cubic foot

This would be polyfoam and ideally I’d recommend 1.8 lb density or above (density and durability are related in polyfoam). The ILD/IFD would tell the “hardness” of the foam, with something in the 30s or above usually considered quite “firm” in polyfoam. A polyfoam with a higher compression modulus (high resiliency polyfoam) will also have a very good support factor and feel quite “resilient”.

The 2" topper: 2-inch thick, 100% gel memory foam 3-pound density foam

At 3 lb this would be a more basic memory foam and below the minimum 4 lb density I recommend. But memory foam will not be firm. Memory foam has low resiliency (not springy) and would be more “mushy” as you described – not at all what you had mentioned you’d like.

A higher density polyfoam or a firmer latex (perhaps Dunlop over Talalay as it has a higher compression modulus – firms up faster), would be two good areas for you to pursue. While not a complete list, there are some various topper vendors listed in the component post here that might be helpful to you.

Phoenix