Page 644 - Handbook of Thermal Analysis of Construction Materials
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612                                 Chapter 15 - Roofing Materials


                                     In 1993 and 2000, the commercial low-slope roofing market in the
                              USA consisted of:



                                   Type                1993 [2]                 2000 [3]
                                                   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



                                                                               [3]
                                     The NRCA’s 2000–2001 Annual Market Survey  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
                                   [4]
                              roads.  Bituminous materials were also used by ancient civilizations such
                              as Egyptians for construction, mummification, waterproofing, preserva-
                              tives, and binders.
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