View Full Version : Disappointed with Homasote
03-08-2009, 08:59 PM
I sheathed the interior of my shed with Homasote today, and put a noisy oilless compressor in it to test it. I was quite disappointed - there was hardly any difference between door open and door closed. The walls were vibrating strongly on the exterior, so I think the Homasote just transmits the vibration right to the studs. I'm now thinking I should have gone with just the insulation and screen. I'm definitely going to have to build a secondary, smaller enclosure for the compressor.
03-08-2009, 09:14 PM
That is disappointing! Back in the day when I was doing HO trains, one of the tricks for the roadbed was to use Homasote because it would dampen the vibration so it didn't sound so much like a toy. I would have expected that it would do a better job. Did you nail or screw it to the studs? Might be worth taking it loose and using some of the green anti vibration caulking to secure it to the studs instead to see if that helps. Another idea is to use a 2x6" lower and upper plate, with 2X4s alternated for studs (takes more 2X4s) so that the inside and outside walls are not as "coupled" together for vibration noise. But my guess is it's a little late for that. Although the separate box for the compressor would probably do the same thing. Good luck! Jim.
03-09-2009, 10:26 AM
I used screws, and, in accordance with the manufacturer's instructions, construction adhesive. I now believe that was a mistake. I'm not going to strip it all off, but I may remove some to expose the insulation in the corner where the compressor is, that will become part of the secondary enclosure. I also think I will incorporate some enclosure scheme in the cyclone stand (same thing - lumber and insulation, perhaps with something different, like duct board, on the outside).
After reading your post on your Homasote installation I checked out a couple of sites on using Homasote for sound reduction. The best I can tell it is used in drywall installations to dampen the drywall by adding mass to it. In addition, it appears that they reduce the sound transmission through the drywall screws into the studs by not directly screwing the drywall to the studs. If I understand correctly they would have you use (special?) adhesive to bond the Homasote to the studs and then screw the drywall directly to the Homasote making sure that none of the screws contact the studs. Additionally, you have to isolate any other items that might make a direct sound path through the wall such as electrical boxes. Based on this information it seems that if you directly screwed the Homasote to the studs and did not use drywall for added mass then you probably lost the benefits of the Homasote/Drywall application. Just a few quick thoughts I hope it helps.
03-10-2009, 08:59 AM
In other words, I went off half-cocked and installed it wrong. I suppose it will all have to come off. Lesson learned. Next time I build a soundproof enclosure :rolleyes:, I'll know what not to do.
Edit: I didn't mean to sound sarcastic toward you, Al T. You're right, I didn't fully understand Homasote's instructions before I jumped in. I'm mad at myself.
I think now, the "cheapest" (that's relative) :( remedy is to use Green Glue or Quiet Glue on a layer of sheetrock directly on top of the Homasote. The Quiet Glue people normally spec 2 layers of sheetrock; they say sound board + QG + sheetrock is OK, but since Homasote is lighter, you don't get the same damping as if you had the mass of 2 layers of sheetrock.
03-11-2009, 12:43 PM
Update: my compressor kicked in sometime in the wee hours overnight. The shed is right below my bedroom window. :eek: :eek: Luckily, the circuit is switched; there's now a new item on my "bedtime checklist".
05-05-2009, 05:44 PM
I'm building a box around my system and am going to try a wall constructed of three layers. The outside/structural part is 1/4" luan with a 2"X2" framework glued and screwed on the outside as a big grid for strength. Then I'll glue old 1/2" foam carpet padding all over the inside surface of the luan with contact cement. On top of that I'll glue the homasote or some 2'X4' acoustical ceiling tiles. My hope is that the mass of the homasote or tiles will absorb the sound, especially the lower frequencies and the foam will isolate it from the outside. I'll post some results when I get it finished. I just got a cool app for my iPhone that measures db. Don't kow how accurate it is, but it should give me an idea.
Can you give me the name of the app and i will check it against my meter and let you know how accurate it is.
05-06-2009, 08:57 AM
It is SPL Meter by Studio Six Digital. As I recall, it was one of the $0.99 apps. I have not tried it yet with the dust collector, but will this weekend. I think I'm in the running for one of the longest owned uninstalled systems mentioned somewhere else in the forum. It's hard to spend time on the infrastructure when I could be woodturning.
Thanks for checking the app. I'd really be interested to see how it compares.
That's the one i purchased this morning after reading your post. I tried at work today and could not located the sound meter so didn't compare but tried it out. Seems like the readings were low for normal voice conversations and in the shop. I expected the shop reading to be low because the mic apparently has a high range of 105 db so i don't know what they are doing to get 120. At any rate when i find our meter I will compare and give definitive results but seems to be about 3-4 db off from what i remember getting with our meter. A running router was reading about 88-90 which seems pretty accurate but i had to hold within inches and aim just right and with the sound meter we usually stand back 5 - 10 feet for the same reading. It will give you an idea if you are making progress in reducing your noise though.
I love my iphone even if it's not accurate!
05-07-2009, 09:03 AM
I hope we're not hijacking this thread going off on this tangent, but...
Thanks for your help. I really wondered how accurate the app was, so now I'll know. Yeah, I really love my iPhone too. I have had several Windows Mobile phones and they just aren't up to the iPhone.
09-14-2009, 11:41 AM
the point of Homasote is that it reduces sound reflection that produces "din" compared to drywall. Two sheets of drywall, the thicker the better, has a better resistance to sound travel through a wall than 1 layer of drywall and one layer of Homasote.
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