TOPIC: I Have An Existing Metal Roof and Have A Question
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I have a standing seam aluminum roof that, along with the house, is 4 years old. Since the house was built I've had noise issues when there is a temperature change around the middle of the day - especially during the Florida summers. The roof pops and creaks. The roof installer insists that it was installed properly and that this a just the behavior of a metal roof.
I'm looking for the simplest and least costly solution - if there is one. One option I'm considering to attenuate the sound is a few inches of cellulose insulation in the attic between the ceiling joists. The attic is sealed with a small A/C vent. The rafters have open cell foam sprayed to an R30 thickness.
I've also been told that it would be better for my plywood sheathing had the builder used closed foam insulation in the rafters.
Any thoughts on any aspect of this will be appreciated. A better solution than sound attenuation? Any downside to sound attenuation with celluloise insulation over the ceiling? Should I, and can I, add some close cell foam over my open cell foam?
Thanks Jim. I am unsure about adding closed cell foam on top of open. I am not sure whether they'd be compatible but I suspect they would be.
I do, though, think that insulation on top of your ceilings is probably a great thing to do.
I am a little surprised the noise is carrying inside the way it is. If you wish, please post a photo of your roof (from the outside) which might provide us better insight.
I was surprised too, but it's pretty loud. Starts around 11 AM and lasts for a couple hours. Occasionally also hear it at night as the roof returns to pre expansion state. The noise is almost all on the west side of the house - the left side when facing the house.
I've uploaded the photo you requested.
Thanks Jim. I am not sure what's going on but the photo isn't loading right for me. It might be on my end -- sorry. Can you possibly email it to me? [email protected]
I just sent you a Word doc with the photos in it.
As for the cellulose over the ceiling, I don't fully understand the moisture implications of having this barrier between the fully air conditioned living space and the barely air conditioned sealed attic.
As for installing closed cell foam over open cell, I'm trying to find a definitive answer if one exists. I don't want to find out the hard way that I've made a mistake that can't be undone, and the opinion of an insulation contractor looking for the work may not be impartial.
Sent the photos in an email a couple hours ago.
Any thoughts on how I can get a definitive answer about installing closed cell over open cell and adding cellulose on top of the ceiling. I have no experience with a sealed attic, and I don't know what moisture issues may result from either of these moves. I don't want to find that I've created a problem by cutting off the main air conditioned living space from the barely air conditioned attic, or what the consequences are of putting closed cell foam over open cell.
Jim, I am sorry ... for some reason, I have not received an email or document. Vapor barriers are often used between the living space and the attic to prevent moisture migration from the living space to the attic. That moisture, if not vented out, can then condense on cool surfaces in the attic. I do not know of any potential problems with spraying closed cell over open cell from the standpoint of moisture. The thing I am questioning is whether it will physically work. Will the two adhere? Will the heat of the new foam reaction cause a problem with the old? Those are the questions I don't know how to answer.
Thanks. I've asked these questions before and no one seems to be certain of the answer - except for the people who will make money from selling insulation.
The issue of closed cell over open cell is the least important of my questions since my sheathing is plywood, not particle board. But the question of adding cellulose insulation for noise attenuation is the tough one to get an answer on. It does seem like one way to keep the roof noise out of the living space, but I can't move on that without being sure that I'm not causing another problem.
I've tried again with the roof pics. roof pics.docx
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