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TOPIC: Leaking

screws backing out

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I heard that the screws in the metal roof will back out and begin leaking within a year or so if you have wood instead of metal beams to screw into. Is this true? Will leaks occur because of this? I also heard that putting metal roofs over existing shingle will cause quicker rusting of the metal due to a type of chemical reaction from the shingle and tar touching the metal. Is this true? I was also told that the air gap between the shingle and metal roof will trap in too much heat and cause your energy bills to go up in the summer. Is this true?
Guest User

7/19/2003
Some metal roofing products are better designed to allow for expansion and contraction than others. All that said, though, I have not seen problems with screws backing out as long as the wood they were going into was sound. Again, though, many metal roofs, particularly those designed for residential application, have allowance for expansion and contraction of the metal. This allowance comes in the form of clip fastening and also small, modular panels. Additionally, many residential products have concealed fasteners. If exposed fasteners back out, will they be a potential leak? Yes. But, again, especially if you're shopping for a residential roof, look for product designs which have allowance for expansion and contraction. Many people are installing aggricultural panels on residences. I personally do not encourage this because those products were not designed for the longevity required by a residential application. Many metal roofs are installed over old shingles. There is no looming negative chemical reaction. However, you should use an underlayment or slipsheet between the two so that the rough surface of the old shingles is not rubbing against the back of the metal roofing. Always, always, obtain and adhere to manufacturer installation instructions! The air gap between metal roofing and the surface below is a good thing. It acts as a thermal break to prevent the conduction of heat. Panels with greater air gap and more consistent air gap will be most effective in this area. There are many other aspects of metal roofing which make it energy efficient including new coatings utilizing reflective pigment technology. Check with your roofing manufacturer! Todd Miller
Todd Miller
Isaiah Industries, Inc.

7/20/2003
We live in Maine and have heard that seamless metal roofing is "better" than the standard raised seam for residential application. Is this true?
Guest User

7/30/2003
In the case of vertical seam metal roofing, "seamless" means that there are no horizontal seams. In other words, the panels are in continuous lengths from ridge to eave. There are indeed still raised vertical seams between the panels. With some corrugated "sheet" roofing, though, there are also horizontal seams between the standard length panels. I hope this helps. Todd Miller
Todd Miller
Isaiah Industries, Inc.

7/30/2003
We have a cabin in the Sierras with a metal roof, the place is about eight years old. Screws are backing out, and we called some contractors about it. One said the screws can be tightened down but gradually the holes in the wood beneath will enlarge, and ultimately the only solution is to re-roof. He said composition shingles are preferable. Do you agree? What is a good solution for the short run? I'm just a homeowner, so please give a non-technical answer.
Guest User

9/25/2003