In the quick video below, I show and explain the Roof Replacement “tear off” procedure:
(BTW, we’re doing this wood-shake roof replacement during the Denver winter on November 18th, 2011.)
A cheap roofing bid will almost always be a “roof over” We are against this practice, and won’t do it. Roof over’s are like putting a band-aid on top of a band-aid!
For proper roof replacement, they must be stripped down to check the sheeting underneath.
A roof that is installed over an old roof will not lay flat. This can cause the new roof to not perform as well, leading to premature leaks and failure. For asphalt shingle roofs, this traps more heat, causing the tar in the roof to evaporate petroleum, leading to cracks and failure.
So we always, always, always (did I mention “always”?) perform a full tear off. The minimal savings isn’t worth what it costs you in the life of the roof. A second layer will cost at least a 10% reduction in the life of the roof… often more.
In every case we know, a tear off will result in a much better roof. Of course, a roof tear-off definitely provides a cleaner look, and you avoid that “wavy” appearance.
In the case of the roof replacement in this video, we’re replacing the homeowners’ wood-shake shingles with the “ultimate” Certainteed Presidential TL shingles, of which we are certified installers for.