There s anecdotal evidence that new shingles installed over old shingles won t last as long as a single layered roof most manufacturers offer the same warranty for both methods.
Roof strip and replywood.
That will suffice on a roof with rafters set 16 inches apart with minimal roof loads.
Input project size product quality and labor type to get roofing underlayment material pricing and installation cost estimates.
The process of removing the existing roof covering repairing any damaged substrate and installing a new roof covering.
In some cases local building codes will limit the available options most do not allow more than two roof coverings on a building.
The most common uses for plywood include support for floors walls roofs and garages in residential construction.
Loads will vary with the pitch of the roof.
However there is no easy universal answer if only one roof is in place.
Most roofs will be sheathed in plywood at least 3 8 inch thick.
Find roof panel closure strips at lowe s today.
Building codes say you can put a second layer of shingles over the first layer but it s better to strip off the old shingles and start with a clean slate.