Homasote

[notCardio]

Homasote has finally become available around here, and I'm looking for opinions on it. Is it worth the trouble? Is it good for some things, not so good for others? Is there a better alternative that's not significantly more expensive?

Thanks.

 

[knightfly]

Homasote is generally only useful as a sandwich material between other materials - for example, between two layers of sheet rock for walls/ceilings - between two layers of OSB or plywood for semi-floating floors - or used as a "perimeter isolation board" to keep a true floated floor from touching the outer walls. The homasote is soft enough to dampen between solid materials.

The advantage of using homasote between layers is that you get two extra "speed changes" as sound travels through the different density layers, hence more isolation... Steve

 

[notCardio]

Thanks for the reply. I understand what it's for, really, I just wanted an opinion on how well it does what it's supposed to do. Is there another material that performs the same function better, or just as well but cheaper?

Are there any special considerations when using it (like, does it require a special adhesive, is it particularly suscepitble to moisture, etc.) ?

Thanks again.

 

[knightfly]

I personally wouldn't use it except for perimeter boards around a floated floor. From what I've read about actual tests, a thinner middle layer of sheet rock works just as well if not better. I've not used the homasote in a sandwich, but if doing a floating floor with minimal headroom it could be an alternative to rubber and joists - just use a layer of homasote under the floor layer. Not as effective as rubber, but better than nothing.

I wouldn't use it anywhere you wouldn't use particle board though, it's crumbly enough it would absorb moisture.

As to adhesives, when you're doing multiple layers in each leaf of a wall you should avoid adhesives. You want each layer in the leaf to act independently, so that there are different resonances and weak spots. That way, the whole is more effective than it would be if all layers were acting as one big mass.

The only exception to that is if you're putting multiple layers directly on studs, then it's slightly beneficial to use a stripe of glue over the studs and fewer screws (16" spacing instead of 12") - the glue makes up for the fewer screws, and the fewer screws decreases flanking noise that gets through by following the fastener into the frame.

Hope that helps... Steve