New wood-framed roofs should be sheathed with exterior-grade plywood or with oriented strand board (OSB) attached with non-popping fasteners. Existing wood-framed roofs should be stripped, and in most cases it will be necessary to apply a new layer of plywood or OSB over the old sheathing. However, if stripping the roof reveals plywood in good condition, it may suffice to drive a ring-shank nail adjacent to each of the original fasteners so that the head of the ring-shank nail overlaps the original fastener to prevent popping.
New concrete roofs should be steel troweled and then cured 30 days before waterproofing. Old concrete roofs should be stripped, pressure washed, and patched. Contact us for advice about installing rubber over metal, foam, and other surfaces.
Before beginning, caulk large gaps and edge transitions, sand or grind protrusions, and round external edges to a 1/2” radius.
See the detail pages in this section for additional preparation procedures.