Modified Bitumen Roofs
Modified
Bitumen roofing systems are typically used on smaller roofs where access
is a problem or when a deck is to be installed over the roof.
Modified Bitumen roofing systems are similar to their BUR cousins; they
come in two generic families. The families are called "APP" and "SBS",
these names are acronyms for their chemical names. In either case, a
material has been added to standard roofing asphalt to "modify" its
characteristics to weather better under normal climactic conditions;
it is then applied to a ploy scrim sheet in the factory and coated with
a granular surface to protect it from the elements. APP roofing materials
have been modified with a plastic material which basically encapsulates
the asphalt molecules. SBS roofing materials are modified with a rubber-like
synthetic which, in essence, becomes part of the asphalt molecule and
changes its characteristics. The typical life expectancy for this kind
of roof is 20 to 30 years. This type of roof is not as hard-wearing
as the typical asphalt and gravel roof system, but is not subject to
bacterial rot as there are no organic materials present.
SBS
roofing products handle the Canadian climate better than do APProofing
systems. APP systems tend to get brittle and pull away at the edges
over time. Anax Inc. does not install APP roofing systems.