Telegraphing - 26 ga over firring strips

Guest User
12/1/2004
We are in the process of installing a metal roof on new construction. The product is 5v profile, 26 ga steel. We have vaulted ceilings, so our construction is, from bottom up: exposed joists, bead board, felt, insulation panels, firring strips, roof. The roof material is attached to the firring strips by screws with neoprene washers. Our contractor is doing the installation himself, without a roofing subcontractor. We're in NC, so even now it gets warm during the day :-) At the end of the day, we notice visible telegraphing - a regular series of horisontal ripples, basically showing where the firring strips are. It's not noticeable at other times of the day. I'm not sure if this is due to expansion or just low angle of light in the late afternoon that creates a shadow. We're considering pulling up the work already completed and putting down a layer of 5/8" plywood. This would add significantly to our cost. Worthwhile? Thanks.
Guest User
12/1/2004
We are in the process of installing a metal roof on new construction. The product is 5v profile, 26 ga steel. We have vaulted ceilings, so our construction is, from bottom up: exposed joists, bead board, felt, insulation panels, firring strips, roof. The roof material is attached to the firring strips by screws with neoprene washers. Our contractor is doing the installation himself, without a roofing subcontractor. We're in NC, so even now it gets warm during the day :-) At the end of the day, we notice visible telegraphing - a regular series of horisontal ripples, basically showing where the firring strips are. It's not noticeable at other times of the day. I'm not sure if this is due to expansion or just low angle of light in the late afternoon that creates a shadow. We're considering pulling up the work already completed and putting down a layer of 5/8" plywood. This would add significantly to our cost. Worthwhile? Thanks.
Guest User
12/2/2004
Personally, yes, I would remove the product, install, decking and underlayment and re-install the roofing. However, it is critical that you find out what the manufacturer of the roofing says is required for their product. I would also do what you have to do to make sure that you have the code-required minimum 1" ventilated airspace beneath the decking.
Guest User
12/2/2004
Thank you. We will check the installation requirements to make certain we have a valid warranty. Please clarify something about the air space: If we pull up the metal, screw plywood to the wood strips, lay down an underlayment, and then reapply the metal, there will be no air space between the metal and the plywood -- it's between the plywood and the insulation panels. Is this OK? Thanks again.
Guest User
12/2/2004
Yes, the International Building Code in this sort of application would require the vented airspace to be beneath the roof decking (plywood or OSB) so it sounds like you have that covered.
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