It’s not happening folks. Roofers are not doing this. Your spec needs to cover your liability for this.
ASCE 7 for 2010 has changed significantly since the 2005 edition. More stringent wind velocities are mandated as well as specific standard that apply to various areas of the roof; the center, the perimeter, and the corners. These standards demand more rigorous design of the entire roof system which includes the roof decking and roof covering (insulation, coverboards, membranes, etc.) Since architects and engineers are responsible for code compliance, the design documents must satisfy the ASCE 7 requirements or face liability for deficiencies.
The major problem that we see is that architects are not paid to watch the entire roofing installation and we are finding non-compliance quite common. The new compliance of this standard requires more fasteners, more quality control of the installation, and hence, costs the roofers more money. In this competitive bidding market, we are seeing a difference of as much as 25% in bids, because some are not providing this additional work, getting the job as the low bidder, and then providing a non-compliant roofing assembly.
There are ways to cover yourself in your specifications.
- State the corner, perimeter and field-of roof uplift pressures as well as ACSE 7 compliance in your construction documents.
- Require the roofing manufacturer’s certification of compliance for entire roofing system.
- Specify rigorous field quality control inspections by a qualified manufacturer’s representative.
- Require pull-out and adhesion testing, if deemed necessary during final roof inspection.
- Require thermographic scan, if deemed necessary during final roof inspection, at the Contractor’s expense. That will get their attention.
- Make sure all of this is discussed and a part of the pre-bid conference agenda.