Civil Engineering Reference
In-Depth Information
In 1993 and 2000, the commercial low-slope roofing market in the
USA consisted of:
1993
[2]
2000
[3]
Type
New
New
construction
Re-roofing
construction
Re-roofing
Built-up roofing
29.0%
31.0%
22.4%
27.8%
Single ply roofing
38.8%
33.3%
38.1%
33.6%
Modified bitumen
17.0%
21.7%
19.1%
23.8%
Metal
3.5%
1.6%
4.3%
2.5%
Other types
*
11.7%
12.4%
16.1%
12.3%
*
Other types = tiles, PUF, liquid-applied, asphalt shingles, metal
The NRCA's 2000-2001 Annual Market Survey
[3]
reported that in
2000, the low-slope roofing market accounted for 64.1% of the total roofing
market, a slight decrease from 68.7% in 1999. The roofing contractors
predicted that the low-slope roofing market would be 63.3% in the year 2001.
Most types of roofing materials are bituminous and synthetic
(polymeric) roofing membranes. The most commonly used roofing and
waterproofing membrane is made by combining asphalt or coal tar pitch
(bitumen) with felts or mats, or fabrics of organic or inorganic fibers.
2.0
BITUMINOUS ROOFING MATERIAL
The built-up roof membrane consists of bitumen, reinforced with
roofing felts, and aggregates which protect the bitumen from the UV
radiation and oxidation. Bituminous materials have been used since 3500
BC. Because of their waterproofing, preservative, and binder characteris-
tics, they were utilized by the ancients for the construction of houses and
roads.
[4]
Bituminous materials were also used by ancient civilizations such
as Egyptians for construction, mummification, waterproofing, preserva-
tives, and binders.
