Central California's
Roofing Experts
Should I tear off my old roof or just roof over it?

Complete removal of the existing roof system is mandatory if it contains moisture, or if the
additional roof layer exceeds safe load design, or if local codes require that the existing roof
be removed. Most local codes will only allow
two layers of 3-tab shingles.

A second layer of shingles can be installed over Dimensional / Architectural style shingles, as
the weight would meet most local code requirements.

Installing shingles over an existing roof system requires proper preparation of the surface.
Blisters, splits and other roof membrane or flashing defects should be repaired in accordance
with good roofing practices to attain a surface which is smooth, dry, clean and free of sharp
projections and depressions. If the roof is not smooth and flat, the flaws will project and be
seen through the new roof.

Finally, the service life of the new shingles should be considered. The U.S. Department of
Housing and Urban Development performed a study which concluded that as much as 25% of
the service life of the new shingles will be lost when installed over an existing layer of shingles
due to heat retention.
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From Our
Proud Member Of
The Following
WARNING: Chemicals
known to the State of
California to cause cancer,
birth defects, or other
reproductive harm are
created by the combustion
of propane, use of hot tar
kettles and tar products.

Our industry is required to
comply with Proposition 65
known as the California
Heath And Safety Code. We
are required to give you
this warning.
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