Roof Curbs – Specifications for Success

The emergence of the design-building process has brought many innovations and excellence in the construction industry. However, the process has experienced some lack of coordination among the parties. One example appears in the specifications that can, in the end, lead to a big problem for the project.

In the case of roof accessories, research shows that the results are roof leaks in the building and lawsuits are expensive against the architect.  The solution is simple. Cooperation and coordination between the architect, specification writer, and the structural/mechanical engineer will assure that the curb support frames will match not only with equipment but will also match roof design.

The path for this coordination is that the design-build team must insist that the roof curbs be in the roof accessories portion of specifications, not in the mechanical section. This is the method recommended by the Construction Specifications Institute. When the responsibilities of the Roof sidewalk specification are assumed by mechanical engineers, it will usually determine that the sidewalk is supplied by the equipment manufacturer.

Sounds good, right? Wrong. The trap is that the sidewalk will fit the equipment, but will not match various roof designs that are applied in conventional metal buildings, and pre-engineering. Furthermore, many of these are knock-down, bolted, or clip lock type curbs that must be field assembled, insulated and shimmed to match the roof pitch. This, then, leaves it to on-site contractors to try to correct problems, adding cost, causing frustration and resulting in future roof leaks.

When structural roof curbs are architecturally specified for all HVAC units, exhaust fans, piping, and other penetrations, the fit is guaranteed — for the equipment, the application, and the roof design. Total roof integrity is maintained.

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