Homasote?

[atgcpaul]

Thanks for everyone answering questions for my new shop (tools, power, etc)

Turns out my home inspector has a workshop in his 3 car garage. For sound
insulation he mentioned a product called "homasote". I've read up on it and
it sounds to be something I will probably use. He said he cut it to size to fit
between his studs leaving a gap on either side. Then he caulked the space
with some special stuff then filled in the rest with fiberglass insulation then
OSB or drywall over that. He says it really stops the sound from coming in or
going out.

Anyone have experience using it? A few years ago I found some kind of
fiber-y 4x8 sheets that I attached to my garage door for sound deadening.
They weren't labeled as "Homasote" at HD. It seemed to work but it was
hard to cut because all the fibers were cross linked. I ended up scoring it
multiple times with a utility knife and kinda' snapping it like drywall. It didn't
leave a smooth edge. That's really my question, how do you cut it cleanly?

Thanks, Paul

[LCHIEN]

I have no idea but here's some suggestions to try:

Electric meat knife with serrated blade
Bandsaw
Hot knife

[LarryG]

"Homasote" has become a "Kleenex"-like word, used to describe an entire class of similar products when it is really a trade name of one specific company. Since you say you've read up on it, you probably know that, also that it is comprised largely of recycled newpaper.

A long time ago in a galaxy far, far away, I worked for a design/build outfit that used a lot of the stuff in apartment construction. In can be scored and broken but we mostly cut it with a circular saw. Makes a mess with a lot of fine dust, so if you do this be sure to wear a dust mask or, better yet, a respirator.

[atgcpaul]

A long time ago in a galaxy far, far away, I worked for a design/build outfit that used a lot of the stuff in apartment construction. In can be scored and broken but we mostly cut it with a circular saw. Makes a mess with a lot of fine dust, so if you do this be sure to wear a dust mask or, better yet, a respirator.

Yup, that's about what I thought. I guess I'll wait until there's a good breeze.

Thanks,
Paul

[RHunter]

Wonderful sound deadening material!!

We used to use it in the theatre to be a top panel over plywood for raised platforms. Prevents the booming from actors jumping all over the platforms.

It is indeed messy and dusty to cut- and not the lightest material if I remember correctly.

[lkazista]

Yeah, we use Homesote whenever we build a set for motion pictures. Really helps.

[burrellski]

Something to consider...

If you do not place some type of sound barrier between your sheeting (osb, sheetrock, whatever) and your wall studs, you will still get some sound transfer through the studs. Some type of sound deadening material in the wall cavities helps, but its not an end-all solution.

[LarryG]

If you do not place some type of sound barrier between your sheeting (osb, sheetrock, whatever) and your wall studs, you will still get some sound transfer through the studs. Some type of sound deadening material in the wall cavities helps, but its not an end-all solution.

Quite so. We design a fair number of sound-rated partitions in our projects, and there's a lot more to it than simply stuffing the wall full of some kind of sound deadening material. Some key techniques:

1. Unbalance the wall assembly from one side to the other, so that the two faces will vibrate at different frequencies. For example if there is gypsum board on both sides, before the gypsum board goes on apply a base layer of Homasote on one side only -- not on both sides.

2. Mount the gypsum board on one side only on resilient furring channels. Again, don't do this on both sides ... the idea is to deliberately unbalance the assembly, so you don't have the exact same mass and makeup of materials on both sides of the wall.

3. Use acoustical sealant at all edges, and around all penetrations (electrical boxes, pipes, etc).

4. Stagger electrical boxes on opposite faces of the wall so they are not in the same stud space.

Constructing a good sound-rated partition is all about the details. Small chinks in the armor can make the whole effort all for naught.

[atgcpaul]

I went to HD last night in search of Homasote and found 4x8 panels. $23
each! I figured for the 3 walls of this garage, I'd need about 25 panels.
That's steep! This stuff cost more than the OSB I was going to cover
the walls with. I can't wait to start pricing the cost of insulation.