# Soundproofing basement in a duplex feedback



## J_King (Apr 14, 2013)

Hello,

I am somewhat new to the woodworking world and I am building a workshop in basement of our rented duplex in the hopes of bring in some income. We share the basement, which means that the noise that I generate down the goes through not only our floor but there's as well. I have spent the last month researching this topic to death and think that I have the wall situation figured out. Due to our circumstances, Lowes has offerd to look at possibly donating the materials, which means I'm limited to what they have. From the research that I've done, this setup should yield me an STC rating of 70 or better.

I'm looking at going with a double wall configuration with a 1" gap in between. One expert mentioned that any latex caulk would work fine, but to put more than one layer one. I think the strapping can be put every 24" apart as well or can it be further? GE has one that says high flexibility that I thought would be a good one to go with. I am also going to use deck screws for two reasons, one because I've found that I like star head screws far better than philips this way I can dismantle the wall if the landlord so chooses if we move and second I can get them in far longer lengths for the extra thinckness of the walls.

The outer wall, closest to the neighbors, I'm thinking of a 5/8" layer of plywood on the outside so that stuff can be leaned up against it an such without hurting it, caulking, strapping vertical, caulking. layer of 5/8" gypsum, caulking, strapping horizontal, caulking, studs 16" on center and filled with 3" fiberglass insulation with the barrier stapled to the studs on the neighbors side to keep dust particles in, caulking, strapping horizontal, caulking, 5/8" gypsum, caulking, strapping vertical, caulking, 5/8" gypsum.

The inner wall would just be 5/8" gypsum, caulking, strapping vertical, caulking, 5/8" gypsum, caulking, strapping horizontal, caulking, studs 16" on center and filled with 3" fiberglass insulation with the barrier stapled to the studs on the neighbors side to keep dust particles in, caulking, strapping horizontal, caulking, 5/8" gypsum, caulking, strapping vertical, caulking, 5/8" gypsum.

Instead of taping all the seams, I was thinking of just caulking them instead except for the final layer that will be in the shop. Also, I was thinking of making my own doors with the same make up of the walls except the final layer on all four sides would be 5/8" plywood. I'm thinking of making two 24" doors on each side that way they don't need a lot of space to open but I can have a 48" opening if I need it.

Now to research the ceiling, not much headroom and my head already touaches the airduct that goes through, I'm only 5'7".

Thanks to anyone that can offer input.


----------



## IrreverentJack (Aug 13, 2010)

Look into the Homosote sound-guard like sheet material instead of sheet rock and plywood. It's lighter and has better sound absorption. -Jack


----------



## J_King (Apr 14, 2013)

Ok, I think I'm going to take a piece from *WorkTheWood* and use layers between the joists, but I'm going to go at it a little differently. Because the house is old, some of the joists are old timbers so I have widths from 7" to 9" and a big forced hot air vent going through the middle that sits 5'7" off the floor.

I changed my plan of using deck screws on the previous plan and going with square drive sheetrock screws. I also went with 19/32" OSB instead of plywood because OSB is supposedly more sound absorbent and it's cheaper.

I'm going to use 3" fiberglass insulation up against the floor, loosely not firmly. Then from there down I'll use acoustic ceiling tiles placed about 1" apart cut to fit and secured in place with just screws. I'll wrap the air duct work with plumbing duct insulation. I'll wrap it twice if I have too. At least it'll be soft if I hit my head  and it should keep any dust out of the system. I think I'm going to staple plastic to the bottom to keep any dust from escaping to the upstairs. Finally to protect all that, I'll use caulking, strapping, caulking, then 19/32" OSB because it's going to take a beating due to being so low. All of the seams will be caulked as well.

Feedback is welcome and appreciated.


----------



## J_King (Apr 14, 2013)

Thanks for the suggestion *Jack*, but because Lowes might be helping us with this project I have to go with what they have because I have to send then the list of materials needed.

Thanks though.


----------



## Ripthorn (Mar 24, 2010)

For the ceiling, your best bet is to add as much mass as you can. When I built out my guitar room, the ceiling got two layers of 5/8" fire code drywall with no stacked seams. Also, you want to make sure everything is as airtight as possible. The ducting is going to be your biggest loss. Remember that sound proofing is only as good as the weakest link. Even if your wall gets you to STC70, if your air ducts only get STC25, then your wall doesn't do you much good at all. I specialized in architectural acoustics through physics grad school and spend a summer doing sound system design and acoustical consulting for a firm in Berlin, Germany and one thing I learned is that having a moderate but uniform STC is better than having a mix of very high and very low.


----------



## J_King (Apr 14, 2013)

*Ripthorn* should I use 5/8" gypsum between the joists instead of the acoustical tile? Also what is your recommendation for the ducting which by the way will be running through my wonderful wall? I'm starting to think this is a bust because of that duct work.


----------



## J_King (Apr 14, 2013)

It looks like the more times I wrap the air ducts the better soundproofing I'll get. One thing about the duct work is that if it's giving me problems I can readdress it because I can't bury it due to it being so low.


----------



## MNgary (Oct 13, 2011)

If I were wrapping the air duct, I'd use marine engine room insulation. It's specifically designed to isolate the engine sound on a yacht.

Ya, I know Lowes probably doesn't carry it so you'll need to pay for it, but your time for installing the walls is a "cost", too.


----------



## Tim457 (Jan 11, 2013)

I've been looking into soundproofing my basement as well. Many of the soundproofing sites I looked at recommended Green Glue noiseproofing compound between sheets of drywall. The drywall provides the mass and the green glue provides the dissipation. If Lowes doesn't carry that, check if they are willing to get it. If not, see if they have something comparable. Supposedly it's quite a bit better than just any caulk. Who knows with marketing of course.

The ducting is the whole problem in my case. If you have ducts, the sound can just pass around whatever other soundproofing you have in place an go through the ducts, unless you handle them. I haven't figured out a way to do it yet in my basement.

Anyway, here's a couple links:
http://westcoastsoundsolutions.com/soundproofing
http://www.soundproofingcompany.com/soundproofing101/
http://www.soundproofingcompany.com/soundproofing101/the-dead-vent/


----------



## Charlie5791 (Feb 21, 2012)

fiberglass is a pretty crappy sound insulator. You'd be farther ahead using Roxul in place of the fiberglass. And I think Lowed carries it.


----------



## sixstring (Apr 4, 2012)

Mass and isolation are the key. Instead of using standard fiberglass insulation, see if you can find Rockwool which is more popular in colder parts of the world. I build bass-traps for audio-engineering/sound-studios which work to absorb both low and high frequency noise/sound. It wont stop the sound dead in it's tracks (you need an isolated wall / seperation and lots of added cost for fully soundproof solutions) but it severely decreases the amount of low and high soundwaves which tend to be heard the most.

If you can, double insulate it using rockwool (or even just standard pink insulation.) IN other words, use twice as much material and compress it into the space (using chickenwire helps) Your neigbors will love you for it and then you can also use your workshop as a sound studio if you are so inclined…


----------



## J_King (Apr 14, 2013)

Thank-you *Charlie*, I just looked it up and sure enough they do. It has no R-value but is sound deadening whichis exactly what I need. This is why I posted this, so that I could make adjustments before finalizing my plans and submitting my materials list. I wonder if I an get away with a staggered wall now instead of the double.

*Tim* - Lowes does have something comparable to the Green Glue, but apparently it makes a mess and doesn't work well. I did a site search and found OSI sound sealant caulk, but when I put in the zip code for store location it gives an error, so I've put it on the list as a possibility for them because it's almost half the price of the GE caulk. Thanks for the links for the vents.


----------



## ScrubPlane (May 22, 2012)

Much like keeping warm on a cold Michigan morning, you want layers that trap both air and noise. A typical wood stud wall with two layers of 5/8 drywall on each side, staggered seams, taped and mudded with mineral wool sound batting in between the studs will provide you a STC rating of between 50 and 55.

A key challenge for you is isolation of the materials as you fix them in place. When fixed together in traditional construction, hard materials (like floor plate to concrete floor) transmit sound very well. You'll want to minimize this with some form of insulation.

Also, any metal ducts and pipes will resonate the sound quite easily and you can utilize non-conductive joints and/or boots if you want to take it to the n'th degree.


----------



## J_King (Apr 14, 2013)

*ScrubPlane* would a staggered wall construction work with my idea of using strapping between the layers and either sound caulk or latex caulk to decouple the material from each other? Also do you think that putting a layer of Roxul sound insulation under the bottom plate suffice?

Thanks


----------



## J_King (Apr 14, 2013)

I checked in with Lowes yesterday to see if they would be able to get the OSI caulking and it looks like they would. They would just have to special order it. They also showed me this Soundstop fiberboard stuff that looks like it could be used to decouple the gypsum because it's very spongy. However, I read on a forum that it likes to grow mold and Lowes would have to pay out of pocket and special order it. So, I emailed the company to find out if it's been treated to prevent fungus and old from growing on it and to see if they would be willing to donate a few sheet and send them to Lowes.


----------



## dhazelton (Feb 11, 2012)

Dumb question and really no one's business, but do you have permission from the property owner? Person I know built a workshop in her rental (told the owner she just wanted to do 'a little light woodworking') with moulding planer, table saw, DP, jointer, new 220 electric lines run….I was there when the landlord showed up and ripped her a new one. She has since moved her shop.


----------



## J_King (Apr 14, 2013)

Yip, a really good question. His primary concern is dust control, which the wall and ceiling sound control will take care of part of that the other part will be the home made Thien dust collector and air filtration system made from the motor and blades from a 20" box fan and a 4" 20×20 filter.

Thank-you for your valid concern.


----------



## dhazelton (Feb 11, 2012)

Good - you have great landlord!


----------

