Dutt Roofing Solutions EPDM Rubber Roof Systems

Built up roof membranes, also called BUR roofing systems,
have been in use in the U.S. for more than 100 years. Started
in the 1840's, these roof systems are often referred to as "tar
and gravel" roofs. Built-Up Roofing (BUR) is one of the oldest
and most reliable commercial roofing systems for buildings
with low-slope or “flat” roof structures. BUR systems
generally are composed of alternating layers of bitumen and
reinforcing fabrics that create a finished membrane. The
number of plies in a cross section is the number of plies on a
roof: The term "four plies" denotes a four ply roof membrane
construction. Sometimes, a base sheet, used as the
bottommost ply, is mechanically fastened. Built up roofs
generally are considered to be fully adhered if applied
directly to roof decks or insulation.

The reinforcing fabrics also are called roofing felts or ply
sheets. Roofing felts are reinforced with either glass-fiber
mats or organic mats. Felts are produced in a standard width
of 36 inches and metric width of about one meter.

The bitumen typically used in BUR roof systems is asphalt,
coal tar or cold-applied adhesive. The asphalt or coal tar is
heated in a kettle or tanker and then applied by mop or
mechanical spreader. Asphalt is a petroleum product refined
from crude oil; coal tar is derived from the distillation of coal.
Cold-applied adhesives typically are solvent-based asphalts
that don't have to be heated in a kettle or tanker.

Surfacing for built up roof systems include aggregate (such as
gravel, slag or mineral granules), glass-fiber or mineral
surfaced cap sheets, hot asphalt mopped over the entire
surface, aluminum coatings or elastomeric coatings.
Over the years, BUR has earned a great reputation with
building owners, architects, engineers, roofing product
manufacturers and commercial roofing contractors. The
original cost of a BUR system may be greater than other low-
slope applications, but when taking the long view, If
installed correctly BUR often comes out a winner. BUR enjoys
a track record that is over 150 years old, provides a thick,
durable roof covering, may be used in a broad range of
building waterproofing applications, and after many years of
service may be maintained and repaired for extended life
(many other systems must be completely replaced).