@Don Merz 070317 posted:Sheet foam isn't perfect--but it's close. For flat or low areas, I don't understand why anyone would use anything else--maybe lots of time and money to waste?
But for mountains, it would cost too much to just stack sheets one on top of another until the desired height is reached. Instead, in mountains 2 feet tall or so, it has been better for me to use the sheet foam on edge, cut to the desired mountain contour topped by the good old cardboard lattice to support the ancient broken-arm plaster castwork surface.
Don Merz
The mountain on my layout rises about 3 feet. Much of it is hollow because I stacked up narrow strips of styrofoam to gain elevation. I found it easier to carve rock formations using the random contours you can produce by stacking strips. Most of the pieces I salvage from the dumpsters were scraps and partial sheets to begin with. Dumpster diving is a very cheep way to fund your landscaping foundation! I used LOCTITE PL 200 construction adhesive to glue them together.
Cheers, Dave