Author Topic: How to soundproof a house insulated with rigid foam?  (Read 4020 times)


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How to soundproof a house insulated with rigid foam?
« on: November 25, 2014, 07:23:01 PM »

I'm happy to have found a great resource for soundproofing, and leave my first post.  I'm about to start a full renovation/energy retrofit of a 1941 1.5 story in Minneapolis.  We are air sealing the entire house, super insulating and replacing all windows and doors to cut energy use to a small fraction of what it is.  What I forgot to consider is sound.  Since we're doing all this work, I also want a noise reduction from outside.  We live under a landing path to MSP airport, so it can get quite loud!

We're intending to cover the inside of the exterior walls with two layers of 1.0" foil faced rigid foam for R-12 (Polyiso) right over the existing sheetrock.  All seams will be taped or foam sealed, and then 3/4" plywood furring strips will be added to hold up new sheetrock.  This is subject to change, however, because I hear rigid foam won't help with noise blocking, and may actually make things worse due to the 'triple leaf' effect of having (from outside-in) exterior sheathing, 2x4 stud wall with old fiberglass batts, 1/2" drywall, 2" Polyiso foam, 3/4" air space and 1/2" drywall.  Is this true? 

Other options include stripping existing drywall and sprayfoaming and then applying the polyiso and sheetrock.  Or adding an additional sandwhich layer of 1/2"sheetrock-green glue-1/2" sheetrock.  I assume rigid foam itself does not have the mass to have any effect when used with green glue.  Unfortunately there is not room for much additional "fluffy" insulation since it doesn't have the R-value per inch we need.

Can anyone suggest any ideas to get the best sound reduction?  Thanks!


Randy S

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Re: How to soundproof a house insulated with rigid foam?
« Reply #1 on: November 25, 2014, 10:26:36 PM »
ok you have a great opportunity to build this correctly.
However it is way to much information for me to post on the forum due to the post size limitations.

I would like you to contact me directly.

here is a video to watch from a similar design as to what i will recommend for you.

Randy S.
760-752-3030 ext 3095
Randy Sieg

Super Soundproofing Co
Ph. 760-752-3030