06-20-2010, 09:33 AM
A helix hidden in a closet does not need roadbed. You can install the tracks directly on the sub roadbed and save that extra 1/4 inch. It may not seem like much, but it could make a difference. In addition if you support it from the sides with metal angle brackets with a maximum of 12 inches between supports, you can also use the thinnest of plywood like 1/8 inch luan, saving you another 1/4-1/2 inch. It might be a little noisy, but sometimes function rules out over form.