I would like to put 8" of rigid foam over a gambrel barn roof, with long fasteners. However, I cannot find a standard guide to the numbers and spacing of screws for the roof. I was going to do screws every 12x12" (horizontally and vertically), but am concerned this may not be enough.
How do I go about finding an engineer to help calculate the appropriate quantity? This seems like a pretty specialized application, and I would want to use someone with experience. Is there a guide somewhere that lists names and numbers of companies who specialize in this area?
In Green building techniques | Asked By John P. | Oct 17 16