Built-up Roof Systems (BUR) and Modified Bitumen Roof Systems are asphalt-based, multi-ply roof systems that can be applied using hot asphalt, cold adhesive, or torch-applied (Modified only).  Built-Up Roof Systems are comprised of multiple layers of Ply IV (4) or Ply VI (6) asphalt impregnated glass fiber mat reinforced roofing felts.  These are typically covered with a flood coat of asphalt and either an aluminum coating or embedded gravel (which protect the roofing felts from harmful UV rays).  However, a Modified Bitumen granulated cap sheet can be used in lieu of gravel. 

Modified Bitumen Roofing Systems combine exceptional elongation and fatigue resistance properties with the strength of a glass-reinforced polyester mat and are available in white, black and other granule surface colors.

The drawbacks to BUR/Modified roof systems is they are susceptible to advanced and aggressive deterioration due to standing water, food grease (such as what is found on restaurant roofs), and UV rays.  BUR/Modified roof systems also are not considered “green” roofs and therefore do not offer heat reflectivity or emissivity and do not qualify for potential energy savings and rebates.

Depending on number of layers of roofing felts, type of surface (gravel, granules, coating), insulation layers, deck type, and installation method, BUR/Modified warranties range from 10 years to 20 years.  However, most BUR/Modified warranties exclude standing water.

If this is the roof you currently have or need help with which type of roof is best for you, ask Professor Haney!

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