In ordinary foam mattresses, the thicker the better
In sofa bed mattresses, there is a design issue.
If the foam is too thick, the mattress feels better right away.
But, after it is folded away in the closed sofa for a little while, the folds
get permanently set.
We have found that:
A 4 inch thick mattress has no noticeable compression set,
even after 2 years folded up.
It is very important to have a high quality foam. Poor quality foam
mattresses will stay folded after just a few weeks.
