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Need advice on dealing with a contractor/sound proofing issue

post #1 of 9
Thread Starter 

I hired this contractor to build my dedicated home theater room.  The room is 13' x 19' in the basement storage area.  Three of the four walls are cement walls.  I'm installing the three B&W 8.2s, four 7.3s and two subwoofers in the room. Here is the dilemma:  I specifically executed a contract with the contractor to install Roxul in all of the walls to ensure I achieve a high STC rating. The contractor made a unilateral decision to install Roxul only in the rear wall (non-concrete) and the rest including the ceiling with either JM R38 or R19 or a combination of both in some areas (think the ceiling).  I contacted JM to find out the STC rating and they responded that they don't have a rating on their products. The contractor had agreed to do a test of sound proofing the room with speakers before installing the drywall but didn't.  I took it the liberty of placing two speakers in the room and could hear the sound all the way up to the third floor of my bedroom.  I sent an email raising concern over the sound and asked that he make corrective action if necessary (since I am relying on his expertise as a contractor).  He has since refused to respond to my emails and his workers are continuing with his project manager only saying that I heard sound because the entry door was detached.  I've sent my second deposit to him (which brings the payment to 80% of the total cost) but can place a stop payment tomorrow. Am I over reacting or would R38/R19 compensate for adequately sound proofing the room if the door was detached?  Any ideas on what I should do?

Edited by jhob98 - 12/15/13 at 3:57am
post #2 of 9
Insulation is just the tip of the iceberg in soundproofing and really all the expert opinions is that between roxul versus fiberglass it doesn't make any difference on containing sound in a home theater. It is the overall wall system and how it uses the four principles that determines how soundproof the space will be. Those principles are Mass, Isolation, Dampening and Absorption. I am unaware of any insulation that even at 12 inches thick will soundproof the space and contain the subwoofer rumble. Couple of things. Google "Bob Golds Absorption Tables" you will find the NRC data for insulation. Just some data for you to compare brands. not STC, that measurement is less dependent on the type of insulation in the wall.

Next read the articles at Soundproofingcompany.com. Bottom, line is that you need two layers of 5/8 firecode (heavy) drywall with green glue between layers mounted on a clip and channel system. I bet they plan on hanging 1/2 inch lightweight drywall (it is actually hard to find the old heavy stuff) which is about as useful as cardboard in containing sound. If your contractor didn't discuss this he doesn't know squat about soundproofing.

If you've paid 80% and they haven't dry-walled, you are way ahead of schedule in paying
Edited by BIGmouthinDC - 12/15/13 at 1:05pm
post #3 of 9
Your contractor used standard insulation because it is cheaper smile.gif

Big basically told you what you needed to know. That said, adding the door to the room (I would ensure it is a solid core door at a minimum) should help. And is their drywall on the walls? If not, that will make difference but it it is too late to add hat channel, and clips (which it sounds like it is) you would want to contact the Soundproofing company before adding double drywall and green glue. At a minimum I would use 5/8 drywall throughout the room, but insulation alone is not enough to soundproof.
post #4 of 9
You might also call the local county or state contractor's board to see if they have any recommendation for dealing with a non-responsive contractor who isn't abiding by the contract. Don't jump to legal actions straight away, but they can likely offer some advice. My local Builder's Exchange was very helpful recently when I had an issue with some construction on our house.
post #5 of 9
Thread Starter 

He installed the resilient clips (not staggered though) and has put the 1/2" double drywall and not 5/8" per the contract). Even with this, I heard the noise upstairs.

post #6 of 9
Thread Starter 

Great suggestion...I will do that tomorrow.

post #7 of 9
Thread Starter 

You are correct. He installed cheap insulation and the 1/2 inch drywall, which is why i'm hearing the sound upstairs. I will reach out to the state board first before I get a lawyer involved.

post #8 of 9
A sheet of the lightweight drywall now being sold at Home Depot weighs 39 lbs. two layers would be 78. A sheet of 5/8 fire code weighs 70 lbs. So you basically have 56% of the mass in the walls and ceiling that you paid for. The easiest resolution of this situation avoiding litigation is to have him add a layer of 5/8 and you will be at 106% of what you paid for. Use the Green Glue when you put it up.

Now did he put putty pads around the backs of all the outlets? Backer boxes on any recessed lights. Use sound attenuation ductwork and caulk all the seams in the theater with acoustical caulk? The door will make a difference but you don't have the mass you need on the walls.

Are there both HVAC supplies and Returns in the theater room. Did he pre-wire for the projector and run a conduit to the projector location?

You should use a heavy 1 3/4 inch thick solid core door with perimeter acoustical door seals.
Edited by BIGmouthinDC - 12/15/13 at 6:24pm
post #9 of 9
I would cancel the check, write up a list of what is not per the contract, and let him low how you want it fixed before he gets the next check. If not fire him and move on. Aren't you the customer?!? Meaning you are the boss....
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