To ensure the wind resistive integrity of buildings within the City of Boulder, the following two wind speed verification options apply for low slope membrane assemblies:
- Engineered Design with City inspection of wind resistive fastening or bonding: A comprehensive engineered design for the flat membrane roof assembly must be submitted at the time of permit application. This design should detail all aspects of the assembly, including materials, installation methods, and load calculations, and number and layout of fasteners or bonding materials to achieve design wind speed requirements.
- Deferred design with wind resistive fastening or adhering inspection by design professional: As an alternative to submitting the full design at permit application, a sealed letter from a qualified design professional approving applicable design parameters will be accepted. This letter must be provided at time of mid-roof inspection. The letter must certify that the installed roof assembly meets all applicable building codes and safety standards, based on a design professional’s review and approval of the assembly. A mid-roof inspection by a city inspector is also required for verifying the Class A Fire Rated parameters of the assembly.
Note: The uplift pressure that must be resisted by building components is determined by the American Society of Civil Engineers (ASCE) design standard ASCE 7. Roof assembly test standards such as Factory Mutual (FM) Global can then be used to specify tested assembly.
Basic Design Wind Speed (V) in MPH| Wind Zone | East of Broadway | West of Broadway |
|---|
| Risk Category I | 140 | 155 |
| Risk Category II | 150 | 165 |
| Risk Category III and IV | 160 | 175 |
If you have any questions or need further clarification, please contact the City of Boulder Planning and Development Services Dept through Inquire Boulder.