Insulating a low-slope roof
We are ready here to go ahead with the insulation of our low-slope roof, and decide to go with closed-cell sprayed foam as you recommended.
We had 3 quotes from local company, and 2 of them proposed to shoot 5-6 inches of foam underneath the 1st deck (in green in the following image), assuming we would remove the interior ceiling.
The third quotes also propose to shoot the same deck (in green), but from above this time, assuming we would redo the roof anyway. He said the roofer could provide them openings in the tar and gravel roof so he can shoot the foam down over the whole deck (in yellow in the image). Then the roofer would replace the tar and gravel roof with a membrane as planned.
I know you were referring to shooting the deck from underneath as a good method, and also to over the roof itself covered by a membrane, but is shooting the in between deck from above is also a good method?
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