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TOPIC: Wind concerns

Extreme Wind Application

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We have a 3 year old home south of Livingston, Montana. GAFs best Timberline shingles were installed originally. I lost about 40 shingles in 3 years. I used about 15 tubes of asphalt caulk trying to keep the shingles glued down. Shingles are starting to blow off in places that never had a problem. These shingles are rated for 90mph. The winds are very gusty and probably no more than 120mph. The wind rarely blows more than 80mph during a rain. Rain blows in the louvered gable vents. I've gotten 4 estimates for a new metal roof. Two contractors want to leave these very thick shingles on (what's left of them), and the other two want to remove them. The decking is 7/16 inch plywood in places and OSB in other places. It's important to us that the new roof be more than good enough. We want some safety margin. A contractor was recommended to us through www.metalroofing.com and it's the lowest bid, and the only one recommending 29 gauge (others 26). I'm not doubting that 29 gauge is adequate, just giving the facts. My question is what do the experts recommend? Standing seam or exposed screws? Thickness? Coating? Anything else to be concerned about? We would like to sleep at night without the worry of roofing flying off, hearing flapping noises, or water leaking inside. Living with this wind is bad enough. Thank you very much for your advice!
Guest User

8/15/2002
Due to the complexity of your questions, I hope it's okay but I am going to email you directly. Todd Todd Miller
Todd Miller
Isaiah Industries, Inc.

8/16/2002
What is the top wind rating on standing seam metal roofs? I live in a hurricane prone area, and I am wondering if metal roofs are going to peel off at 100+ miles per hour. Any advice. [email protected]
Guest User

8/19/2002
What is the top wind rating on standing seam metal roofs? I live in a hurricane prone area, and I am wondering if metal roofs are going to peel off at 100+ miles per hour. Any advice. [email protected]
Guest User

8/19/2002
Wind places many stresses on a building, in particular roofing. You can have pressure on one side of the roof while having uplift on the opposite side, like an aircraft wing. The pitch and form of the roof coupled with the height of the building, wind direction and toporgraphy all have a bearing. The major tests that are used is first the UL 580 where a roof section is placed in alternate 30 second cycles of pressure and vacumn to try and duplicate a high speed wind storm and second the UL 1897 which then vacumns the roof off the structure and measures the fail point. Both of these tests are required to meet the South Florida Building code which is recognised along with the Texas costal areas as having the highest wind standards. Basically ask the manufacturers of the products you are considering if they carry this testing.
Allan Reid
Dura-Loc Roofing Systems, Inc.

8/20/2002