I am writing to enquire about sound deadening strategies for a 17-year old guest bedroom roof that is part of a house addition. The few times I have been up there when it rains, I am surprised of how noisy it is. The noise by itself is not prompting me to make a change but since a tree fell through the roof, I now have an opportunity to address it. I plan to replace the damaged portion and reshingle the entire addition. This portion of the house roof profile comprises (i) a basic asphalt shingle, (ii) 15Lb or 30Lb felt/tar paper, (iii) ½” Plywood, (iv) 2X10 rafters with stryrofoam vent channels and R30 fiberglass (pink) in between, and (v) ½” drywall.

I plan to replace the basic shingles with a slightly thicker architectural shingle that is used on the remainder of the house (replaced 7 years ago). Initially I considered adding a layer of foam board with an additional layer of plywood on top but that proved to be an additional $3,000. The alternative, I am considering now is to simply go with a thicker felt or tar paper, perhaps even doubling up 30Lb felt/tar paper. Are there issues with doubling up tar paper? I wouldn’t want to inadvertently create moisture or other problems. I’d also like to hear whether people think this will help reduce noise. Finally I would be interested in any other options that I should consider?