[DeeBunker]

I've done some searching on this and I'm struggling to find any data that shows the effectiveness of sound isolation brackets. I'm talking about the rubber (I think it's rubber) pad mounted to steel L-bracket things used for attached walls to other structures while keeping them isolated. I know plenty of people here use them when building walls in their basements - basically keeping the top plate 1/4" or so shy of the joist and holding the wall up using the brackets. I've also perused many theater builds where people did not use them.

Anyone know of any test data that shows their effectiveness? All I could find was one website that claimed an STC improvement of "at least 7". I'd like to hear anything about effectiveness, even if it's just anecdotal. For example, is a 2x4 wall with one layer 5/8 drywall and top plate attached to joists using isolation brackets better or worse than a wall with top plate firmly nailed to joists but with double drywall and green glue?

Has anyone built their own isolation brackets using readily available hardware store goods?

One thing that bothers me is the thought of using such a bracket to hold up a wall that will have a heavy door built into it - I usually like to assembly such things in a very solid, rigid way.

Thanks,
Chris

 

[BIGmouthinDC]

if sound isolation is a goal you need to let go of the notion of attaching everything in solid rigid way as that provides a mechanical pathway for vibration transfer. The brackets don't hold up a wall they just keep it from tipping, a wall in a plumb upright position has very little horizontal force and once the ceiling and wall drywall are locked in a cascade assembly that wall isn't going anywhere. if you aren't using at least two layers of 5/8 drywall I wouldn't bother with framing isolation.

I use a one inch gap, 1/4 inch is cutting it too close and any floor/ceiling variances can undo your efforts. Building a room within room is a well established sound isolation technique I agree it is hard to find good data because of the difficulty in finding two identical rooms to measure different building designs and the effect on sound transfer throughout the structure not just on the other side of the wall which typical testing procedure.

 

[DeeBunker]

if sound isolation is a goal you need to let go of the notion of attaching everything in solid rigid way as that provides a mechanical pathway for vibration transfer. The brackets don't hold up a wall they just keep it from tipping, a wall in a plumb upright position has very little horizontal force and once the ceiling and wall drywall are locked in a cascade assembly that wall isn't going anywhere. if you aren't using at least two layers of 5/8 drywall I wouldn't bother with framing isolation.

I use a one inch gap, 1/4 inch is cutting it too close and any floor/ceiling variances can undo your efforts. Building a room within room is a well established sound isolation technique I agree it is hard to find good data because of the difficulty in finding two identical rooms to measure different building designs and the effect on sound transfer throughout the structure not just on the other side of the wall which typical testing procedure.

Hi Jeff,

In some cases I already have load-bearing walls in my room and I'm adding walls. Many of my projects don't allow for the all-out room within a room approach as it would require way too much tear-out or adding thickness to walls (ie using channel).

Your suggestion to not bother with isolation if not using double drywall has my head spinning a bit. What I'm trying to sort out is the value of wall assembly isolation compared to mass/dampening. Does your comment mean that you see the mass/dampening as far more valuable than direct vs isolation bracket mounting?