As many of us do when I decided to build my layout I used mainly what was on hand including three wood kitchen tables. I built some connecting sections of open grid from 1x4, adjusted heights and covered everything with 2" or 1" foam. I run mainly postwar type trains. Foam provides plenty of support but the one section of foam just on the grid is noisy even for me. Its the unsupported foam acting like a drum head between the cross pieces. On modules this might not be an issue as there is a weight trade off.
David
