gambrel roof or gamble roof!?!?

colette granger
12/4/2017
Hi, I am planning to have 29 ga metal installed on my gambrel roof. Currently there is one layer of asphalt shingles. Roofer says it's not t to remove the shingles but just to apply 1X4 straps, but I'm not sure, as my only experience is with asphalt and it's generally best to start fresh rather than double up. I'm not sure whether he plans to install an underlay of any kind. Is underlay (a) necessary or (b) beneficial either with or without the old shingles still there? Also, my house is right beside the ocean in an fairly high-wind area (if this makes a difference for any of the above). Thanks!
Todd Miller
Classic Products, Inc.
12/4/2017
Chances are what he is doing is fine. I personally would still use underlayment over the old shingles even if battens are installed. Many people would not. I would also prefer a direct to deck installation given the potential for high winds, Is there any way to talk to him about what would be involved to do a direct to deck installation, whether or not the current shingles are removed? How is your attic ventilation? Thanks.
Dick Bus
12/4/2017
in addition to what Todd is saying and since you are right on the ocean, I would recommend that you consider installing an aluminum roof.
colette granger
12/5/2017
Thanks for your reply. I will certainly speak to him about the options, but I wanted to have a bit of info before I do so. There is no attic in the house, so the only roof ventilation is through the soffits. Does this create a concern? I gather from what you write that it's okay to install underlay over shingles. Is there a particular type that is best for this situation? And I don't understand what you mean by "a direct to deck installation, whether or not the current shingles are removed" -- doesn't direct-to-deck, by definition, mean that the shingles would be removed? Thanks so much for your patience and your replies!
colette granger
12/5/2017
Aluminum doesn't seem to be an option in my area; I have talked to a number of companies and they only do steel. However, the product I'm considering is "bare steel covered with a mixture of zinc, aluminum, and trace amounts of silicon". I'm also told there is a 40-year materials warranty. Does this sound ok? Thanks!
Todd Miller
Classic Products, Inc.
12/5/2017
Proper attic ventilation helps with winter and summer energy efficiency and also helps with avoiding roof top ice dams in the winter. Proper ventilation includes intake and exhaust vents.Right now, you have intake vents in the soffits but no exhaust vent sin the roof. A great source of information on venting is available at www.airvent.com Many contractors have switched to synthetic underlayments. There are many good ones available today. Direct to deck basically means without battens -- the old shingle stay or may not be present. All steel products have some anti-corrosive metallic coating. I second what Dick says - aluminum would be preferable.

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