Insulation, Radiant and Vapor Barriers - Do I need interior wall insulation?

Having a new home built. Have the option of adding interior wall insulation. I'm comfortable with insulation that comes standard. I have been told that the interior wall insulation will help reduce noise, which is what I am most interested in. Is this indeed the case? Does interior wall insulation help reduce noise significantly?

Thanks!

Insulation alone in an interior wall will not reduce sound transmission significantly. It will help some, but not a lot. Problem is that the wall is built with a 2X4 stud and sheetrock put on both sides. Sound will transmit through the sheetrock and studs. To really attenuate the sound, you would have to have a 6" or 8" wall, with seperate studs for each side, then weave the insulation through it. It requires a lot of extra time and material to build such a wall, and usually isn't worth the expense, to either the builder or the buyer.

If you are comfortable with the standard insulation, go with it. If you want to spend extra money on insulation, have them add 6 more inches in the attic. That will do you more good than insulating interior walls!

Adding fiberglass batts to the interior walls will dramatically reduce sound transfer.. It is not sound proofing but will make a dramatic difference.. The cost is minimal especially if you do it yourself.
Approximately 24 cents a square foot..


All u need to install is an unfaced 3 1/2 " fiberglass batt R-ll. make sure the batt fills the entire cavity. Also foamsealing behind electrical outlets on interior walls, caulking the gaps in doublers will reduce sound transfer.

For further details on sound transfer ratings visit Owens Cornings web site..

If I was building a home I would sound all baths, bedrooms and the laundry room..