To Build or Not Build a Frame?

[RobertInOntario]

The only reason to use a frame would be to protect the edges from damage. To strengthen the foam so that is doesn't break, just glue a piece of luan door skin cut to the same size to the bottom of the foam. Foam is very strong, but if an uneven force is applied, or you fall or lean against it and it is not supported on a flat surface, it can snap in two. The 1/8 inch door skin will support it so that you could even put it on legs and it would not break. If you want to extend the sides, cut the door skin to fit the expanded size and glue pieces of foam to extend it. The added pieces will be supported by the door skin. Otherwise, without support, you will need to start over with a new larger piece of foam.

Thanks, Russ. This sounds like an excellent idea. I'll look into it at my local Home Depot (conveniently, only a 5-min. walk from my house!). Rob