Basement workshop soundproofing

[Shawn Edmondson]

(First post -- this is an excellent group, thanks for all the detail and great project pictures.)

I'm planning a shop in the framed (but unfinished) basement of our new house. (No more brushing grass clippings out of jointer knives.) Here's my current noise-reduction plan -- I'd love advice on noise improvements and expense optimization.

I need to cover 250 sq. ft. of batt-insulated 10' ceiling, which has 12" "joists" (prefab girders made of 2x4s -- what do you call those?), and 26 linear feet of 2x6-studded walls between the shop and the rest of the to-be-finished basement. The remaining walls are concrete.

Ceiling plan: Cover with 3/4" plywood or OSB. Attach resilient channel to the ply, and hang two layers of 5/8" drywall from that. (No idea how to actually do that without breaking my neck, but it looks good on paper.)

Wall plan: Toenail 2x4 studs evenly spaced between the existing 2x6 studs, but with the 2x4 extending 1/2" past the plate into the shop. (Retrofitted staggered studs.) Sheath the 2x4s on the inside, and the 2x6s on the outside, with plywood, OSB or drywall. Fill with fiberglass batts.

Misc: Run exposed DC ducts and wire conduit/outlets to avoid poking gaps in the walls, and caulk everywhere. Weatherstrip around the door. Cross my fingers the first time I fire up the planer and discover whether the whole project was a waste of time. :)

My cost estimate for the above plan comes to just under my goal of $1000.

Actually read this far? Thank you! Any advice is hugely appreciated.

Thanks,
Shawn

[Jim Becker]

Sounds like a pretty good plan to me, Shawn. I'm not sure that the plywood on the ceiling is needed, however. I'd use drywall there (cheaper) since you're really just looking for an air space. between the two layers.

BTW, welcome to the 'Creek!

[Chris Padilla]

Shawn,

Scroll to the very bottom of this thread for the similar threads list and click on Jay St. Peter's long but good thread. It'll open your eyes and you'll see that your ideas need some adjustment. :)

[Wes Bischel]

Shawn,

Welcome as well. Sounds like you've done your homework!
I agree with Jim, use drywall instead of the plywood. Along with the airspace, the mass will help deaden the sound so using 5/8" will help as well. (OBTW I would rent a drywall lift - it will save you in more ways than you can count) Along with the weatherstipping, the type of door will make a huge difference. A typical hollowcore door will defeat all you have tried to do. A solid door, or a commercial door/frame with a STC rating would work, but will cost more.
You may also want to consider sound absorbing materials after your steps have been taken. Not only will it make the space more pleasant to work in, but it also cuts down on the amount of sound energy your other work will need to block. (like a fiberglass or mineralfiber ceiling or fabric covered baffles)

Food for thought,

Wes

[Chris Padilla]

Guys,

In general, simply screwing drywall to the ceiling will not help with sound deadneing all that much. The sound waves will simply vibrate the drywall, which because it is so well secured to the joists, will vibrate the joists and thus transfer the sound.

What one needs to do is to allow the drywall to vibrate but not allow it to then vibrate the joists. One way to do this is to isolate it from the joists or quite literally, float it. What most do is secured metal strips across the joists. These metal strips (often called RC-1) are secured to the joist thorugh special hangers such that they, too, are isolated. Now you only secured the drywall to the metal strips and not the joists. It is important to not "short out" the drywall to the joists or you will ruin the ability for the drywall to float and vibrate without vibration transfer.

Basically, that is the gist of creating sound-deadening. Try reading up here as well, it is a good informative website: http://soundproofing.org/. Another alternative is what I did in my garage: http://www.quietsolution.com/

All this stuff is not cheap unforuntately but the first website will teach you a lot about what you can do and then you can let your pockebook talk from there.

[Jim Becker]

It sounds like he's using the channel based on the original post.

[Chris Padilla]

Doh! You'd think I'd learn by now to NOT skim posts.... :o

[JayStPeter]

You're on the right track. I think the money spent on ply/osb could be better spent though. It may even be a negative on the walls. I think homosote/soundboard would be better. I'd also put some insulation in your makeshift staggered stud wall. Use the stuff for 2x4 walls so you have an air gap also.
As Chris pointed out, my basement soundproofing effort is detailed in this thread (http://www.sawmillcreek.org/showthread.php?t=10597) . The link he gave is good info to study before you start. It is time consuming to pull the useful (ie low budget) stuff out though ;) .

Overall, I'm happy with the results I got. The planer is still a minor annoyance if you sit directly above it. Apparently it's not enough of an annoyance to justify a sprial insert cutterhead model though :( . I can work at night while everyone sleeps two floors above no problem. While I was building the basement, the miter saw sounded like it was right there in our kitchen. Now you have to listen to hear it.

I think you'll find the effort worthwhile. Let me know if you have any questions and I'll try to answer them as best I can.

Jay

[Bartee Lamar]

Use Rock Wool insulation. As much as you can. This is much heavier and will help absorb sound.

If you really want to get crazy you can use two different layers of wall covering. (Like sheetrock and plywood or wafer board). Different materials will stop different frequencies. Actually MDF would make a good sound absorber.

Put down rubber mats on the floor. Concrete will bounce a LOT of sound waves.

You will still transmitt sound thru the heating/air ducts. Not much way to stop that.

Good Luck and enjoy building your new shop.

[Chris Padilla]

Air ducts can be tamed down in two ways:

You can add absorber faom to the inside of the ducts as far as your arm can reach or that you are willing to take stuff apart.

Also, you can make the sound entering the duct go through several paths (i.e. like a bunch of interlaced chambers) before it actually enters the duct. Of course, this will have an impact on air coming the other way through the duct but you can experiment and find a happy medium.

[Shawn Edmondson]

Wow -- thanks for all the responses, links, and patient repeat answers. Definitely makes sense to skip the ply.

Glad to hear that the miter saw isn't annoying upstairs. That's the key validation I was looking for (some hope that this is going to work). I like the MDF idea; it holds screws better than drywall. I'll check out Homasote too. Time to find lumber and hardwood dealers near Raleigh, NC. (A whole other search.)

The good news about my space, noise-wise, is that there are no ducts or windows -- it could potentially be an airtight tank. The bad news is that there's no ventilation either, and I don't want to win a Darwin award the first time I apply a finish. But adding ventilation is a whole other search/thread too.

Thanks again,
Shawn

[Bart Leetch]

I'd also put some insulation in your makeshift staggered stud wall. Use the stuff for 2x4 walls so you have an air gap also.


Jay

Quoting Shawn

"Wall plan: Toenail 2x4 studs evenly spaced between the existing 2x6 studs, but with the 2x4 extending 1/2" past the plate into the shop. (Retrofitted staggered studs.) Sheath the 2x4s on the inside, and the 2x6s on the outside, with plywood, OSB or drywall. Fill with fiberglass batts."

So Jay are you competing with Chris for the skim the post award? :eek: :D

[Bart Leetch]

Shawn

Before you decide what sheeting to put on you ceiling & walls check with your insurance agent they may not let you use anything but sheet rock for fire resistance purposes.

[JayStPeter]

Quoting Shawn

So Jay are you competing with Chris for the skim the post award? :eek: :D

I think Chris and I are often on the same wavelength :rolleyes: :cool: .


...

If you really want to get crazy you can use two different layers of wall covering. (Like sheetrock and plywood or wafer board). Different materials will stop different frequencies. Actually MDF would make a good sound absorber.

Put down rubber mats on the floor. Concrete will bounce a LOT of sound waves.

...

You're right, multiple layers of different materials is ideal. Homosote and drywall are complimentary products that each absorb or reflect different frequencies. MDF is an interesting material also. You have to remember that there are two ways to keep sound out of an adjacent area: absorb it, or reflect it back into your own area. You also have to be careful of things like plywood. It will reflect some frequencies, absorb others, and transmit others like a soundboard (think guitar). Adding the necessary damping to keep the transmitted frequencies outside the audible range makes it pretty cost ineffective as a soundproofing material.

Rubber mats on the floor will decrease sound level in general, but mostly inside the shop. I wouldn't expect it to make a huge difference outside of the shop. Unless the rubber mats are under machines to keep vibrations from transmitting into the floor, I would consider it more of an acoustic treatment than soundproofing. While acoustic treatments and soundproofing are related, the best bang for the buck (or $1K in this case) would be to concentrate on the ceiling and walls.

Jay

[Chris Padilla]

I think Chris and I are often on the same wavelength :rolleyes: :cool: .

Hmm, let's see now, would that be calculated used the speed of light or the speed of sound! :confused:

;) :D

[JayStPeter]

Hmm, let's see now, would that be calculated used the speed of light or the speed of sound! :confused:

;) :D

In this thread, definitely sound.

I really don't know if my brain is capable of light speed anymore. I think my kids have done more damage to it than partying in college :eek: :D .