26 September 2006
Table 1-1. Relationship With NRCA Manual
Low slope Membrane Roofing
Design Guidelines for Low slope Membrane Roof Assemblies
Use MBMA in combination with NRCA
Chapter 2, 3 & Chapter 5
Appendix A is the glossary of acronyms and abbreviations. Appendix B is a reference
list. Appendix C provides considerations on roof warranties. Appendix D provides
quality assurance guidelines. Appendix E provides other resource documents.
At no time in the history of roofing has there been such a wide choice of materials and
roofing systems available. Satisfactory roofing performance comes from careful
selection, design, specification, installation, and maintenance.
Roofing systems are exposed to the full brunt of the weather and can leak or fail
prematurely if not properly designed, installed, and maintained. Leakage can be costly
and adversely affect the functions within the building. Since modern roofing systems
contain considerable thermal insulation, moisture intrusion lowers thermal efficiency and
hinders energy conservation. Wet materials support fungus or mildew and can emit
odors leading to sick buildings and occupants.
There are two starting points in roofing system selection:
In new construction, the roof system selection is an integral part of the overall building
design. For example, the building can be designed to support a heavy roof system or
the roof can be sloped to accommodate the minimum requirements for the desired roof
When dealing with an existing structure, weight, slope, and existing materials all
become constraints. For example, the weight of the roof has a major impact on