Quote Originally Posted by neal View Post
I live in a 3 yr old house; single story, 1850 sf, double pane low e glass, with foam(open cell) insulation in the ceiling(against the inside roof decking) and in the 2X4 walls. The house is very energy efficient but has a lot of street noise. A real surprise to me.
I considered re-insulating the interior walls by putting up additional studs and filling it with insulation (really too expensive) and considered putting insulation in the attic ceiling, but builder said it would cause a moisture problem. I even considered a much hyped NASA additive to put in exterior paint. This may work, but can't find anyone-outside the industry- who would say that it does. The cost is the paint, the painter's time and the cost of the additive (which in it self expensive).
Does anyone have any ideas on how to reduce the street noise short of putting in street bumps, wearing noise canceling headphones or selling to a deaf person? Please help me??
Depending on what type of traffic noise you can reduce a portion of the noise with shrubs, trees and fences . A large portion of traffic noise is tire contact with the road surface. Dense shrubs at about 3 ft height will go towards reducing this sound. Along with other plantings and a barrier fence are the first line of reducing the noise that reaches the house.

Dual pane windows with different thickness of glazing also improves the SPL. The various thickness reduces the noise since they attenaute different frequencies.
Applying rigid faom to exterior also reduces noise infiltration.

I'm sure you don't want to completely redo your 3 year old home so, a simple thing on the interior is apply 5/8 drywall or a special sound proofing drywall to the exterior walls facing the traffic.

I'm not sure how much noise is coming in from the attic but --- sight unseen --- if your attic is insulated creating a conditioned space then adding batt insulation to the ceiling rafters shouldn't be an issue with moisture.