New Roof Guide

Roofing Layers

Before considering materials, examine the integrity of an existing roof. There are three basic considerations to help you decide whether new roofing can be installed directly over the existing roof or whether the old roofing will have to be removed first, according to the National Roofing Contractors Association:

-- Building codes specify that if a roof has two or more existing coverings, they must be removed before new roofing is installed.
-- If the roof has a history of leaks, evaluate it for structural damage that might not be remedied by simply adding another layer.
-- Certain heavy or high-definition roofing materials, such as tile or wood shakes, must always be removed because they can't be covered.