My problem is the reverse of most people here - I'm trying to keep noise out.
The house is a small 1960's timber framed cottage, good location - 200 yards from the beach and surrounded by trees - but it's become very noisy in recent years.
There's a main road about 50 yards away that gets busier each year and my nearest neighbour has turned into a hell man - added a big deck right near my house, a new dog with a big woof and a thumping new stereo - he likes to party hard.
I've been researching this whole acoustic building thing for about five months now and tied my brain in a knot so many times I've lost count.
Man, I was so relieved when I found this forum - thought I was the only one grappling with all these different standards, minutiae construction details and conflicting information from different suppliers.
Regarding RC v direct fixing, I seriously considered RC for this room and bought a length to get familar with it. The room has three exterior walls and a low slope metal roof. After listening to all the different types of noise coming into the room, the ceiling is the main source of the most disruptive noise - the neighbour's place - which sits higher than mine. The three exterior walls get the traffic noise.
So for the ceiling I'm using rubber isolation (resilient) mounts to suspend furring channel and fixing two layers onto the furring channel with 125mm of insulation in between the new lower ceiling and the metal roof.
This is what the mounts look like...
According to the test results, these mounts increase STC ratings by about 5 points. This is the supplier of the mounts
http://www.gyprock.com.au (The "System Selector" on their site is a good source of tested wall systems and there's masses of PDF's with construction information.)
Getting back to the exterior walls, I'm aiming for an STC of about 45 - more would be good - but I think that will take the edge of the traffic noise.
The interior wall (which faces the neighbour) is getting the same treatment to deal with noise which comes through the roof and any open windows in other parts of the house.
The cavity bewteen the wall studs, I've filled with 75mm Rockwool and am planning to direct fix 2 layers of different types of materials - one layer of 1/4" (6mm) fibre cement (10kg/sq mtr) plus one layer of 5/8" (16mm) fire plasterboard (or sheetrock) (12.5kg/sq mtr).
I'm not sure what you guys call fibre cement in the U.S. but there's info about it here
http://www.csrfibrecement.com.au.
Test results for this fibre cement/sheetrock combination are the same or better than a straight sheetrock/sheetrock combination. It also helps keep the wall thickness down which saves me having to move the door, deal with an even smaller room and various other issues.
Here's a sample of test results for this wall system.
(The link had to be cut into three lines to avoid horizontal scrolling in this thread. Copy and paste each line into your browser address window so they make one long link.)
Code: Select all
http://www.csrfibrecement.com.au/designlink/systemselector.asp?
Display_Records=10&RP=1&sysNo=csr665&use=&type=&wet=&Wall
Height=height&FRL1=&FRL2=&FRL3=&RW=&RWUser=&SUBMIT1=Find+System
Windows are being upgraded to match with a double window of 6mm and 4mm glass and an 80mm air gap. I've also built an 8ft air duct (with similar insulated walls and insulated ducting) on the side of the house to bring air in fresh air.