4.8 ROOFING SYSTEMS
The design and construction of roofing systems is discussed in the NRCA (National Roofing
Contractors Association) Roofing and Waterproofing Manual. The NRCA manual contains a
thorough treatment of roofing issues such as basic design options, membranes, insulation,
sealants, flashing, drainage, and expansion joints This section concentrates on those issues that
are crucial to the heat, air and moisture transfer performance of roofing systems through the
maintenance of the continuity of the envelope insulation and air barrier systems.