This is not my house. I read this elsewhere,
edit–I need to retype this, it made no sense.
A guy a know got a quote for a new metal roof
the quote was to add purlins on top of the exisitng shingles, add a spray foam onto the shingles and then install the metal.
He was also told it would reduce his colling costs 15%
1) is it a good idea to leave the old shingles on?
2) is this 15% reduction true?
Just wondering.
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WWPD
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Replies
15% reduced cost for cooling? Probably so, obviously depends on insulation and color selection. I put 2 metal roofs on my properties after the hurricane. R-Panel, color light stone-- my tenants claim great savings.
I pulled up the first coarse of shingles to attach 1x4 treated purlin, went up the roof the rest of the way 2' OC with the purlins on top of the shingles -all treated lumber. I didn't add any insulation, only because I'm not paying the electric bill.
In my area- South Louisiana- a lot of people are moving away from glass batts, foam and the like for roof/ attic applications, and are using more low e film and reflective bubble wrap. The thinking is that glass batts and foam have a tendancy to hold in more heat. It was a hard sell for me at first but I'm a convert now.