Prior to the development and implementation of comprehensive building codes, it was common to install roof systems without permanent connections to building structures. The idea is that the weight of the HVAC climate module will be sufficient to support the pavement and roof modules at the top of the building.
Recent studies on the impact of natural disasters indicate that roof units must be completely prevented from moving with their curbs, and mechanical roof curb must be attached to building structures to withstand earthquakes and wind loads. This study is changing the way roof curbs are designed, built, and installed.
Many U.S. jurisdictions require licensed engineers to comply with applicable building codes and limits. The process by which the pavement is now designed can be summarized in three steps. First, the pavement roof designer must determine the building code for a particular project. This information is usually provided in the mechanical or structural section of the project specification. Planners should also be aware of design requirements.
After applying the applicable building codes, the second step for the designer is to determine the design force of the earthquake or wind loads that the roof beams and sidewalks must withstand. Generally accepted building codes in the United States provide a step-by-step procedure for determining design strength. A designer's third step is to determine the requirement for attachment of rooftop equipment to a curb and the curb to a roof.