OT Workshop Soundproofing/ Noise reduction

[SteveD]

After a long wait I am finally getting around to planning the conversion of a 15' 6" square basement room to a Festool workshop. The walls are all bare concrete block, the floor is bare concrete and the ceiling is steel decking. One wall adjoins a 15,000 gallon water tank (ergo do not drill into it!) and the opposite wall is next to a basement bedroom of the adjoining unit. Above the ceiling is our living room floor.
I plan to render (cement/sand) the tank wall, seal it with Dry-Lok and then build a stud wall so I can hang stuff. The other three walls, the floor and the ceiling are open to 'discussion'. Obviously any additional stud 'walls' will reduce the size of room, however that is a trade off of benefits.
Most of my large work is with sheet goods which I can just about get into the room.
According to what I have read there are two sides to the noise problem. One is to reduce the sound generated/reflected within the room itself and the other is to reduce the transmission of sound (into and) out of the room.

1) One product that has caught my eye has been 'Green Glue' to put between layers of drywall to reduce sound transmission. Has anyone experience with this product? The concept is very simple - but how does it work in a workshop environment where most of the noise is low frequency?

2) Noise reduction includes sound absorbing surfaces on the walls and ceiling. Has anyone experience with successful (or tales of the unsuccessful!) wall and ceiling surfaces that do not gather dust or break the bank yet help to reduce the noise factor.

3) I will likely need to install three vents, two to bring fresh air in (one direct from outside and the other from the main part of the house) and the other to expel air out of the building. Both need to reduce the noise as other neighbours may not appreciate the sounds of sanding or sawing at night. Again does anyone have suggestions or websites they recommend? (I know not to expel too much air-conditioned air.)

4) Neither the floor nor ceiling are horizontal. I don't think the builder had a level that worked in that plane. Therefore I will have to level the floor and put on a suitable surface. I am looking at something softer than ceramic tile (the rest of the house is that) such as a poured floor or sheet vinyl. The ceiling will likely be drywall with lights and some sound absorbent surface.

I am of the opinion that it is better and less expensive to do things right the first time. That is what got me buying my Festool tools in the first place. My email address for any replies you may not want to share online is woodworking@dunkerley.com.

Thanks
SteveD

 

[Brice Burrell]

Steve, I don't know a lot about sound reduction, I'll give you a few thoughts anyhow. First, I've never heard of 'Green Glue', so I can't offer any meaningful comment on the product. If you can afford to lose the space on the ceiling I'd really soundproof that as much as you can. I'd stay away from drywall and go with a drop ceiling, acoustical tile and insulation above that if you can. The wall that you share with the other unit must also be well insulated. Stand up a 2x4 wall, not touching the existing wall so not to transmit the sound (as much). Fiberglass is pretty cheap compared to the products made specifically for soundproofing. But fiberglass is really only so-so at soundproofing. As for the ducts, insulated metal duct work could be the best option if you don't have room the round flexible duct. On the floor you could just put pad and carpet down. Of course the floor would have to be dry and you couldn't roll large tools around very well on carpet. A wooden floor would be my first choice, if you can swing it. Other members here can probably offer better advise, but this is my 2 cents worth.

 

[neoshed]

I would skip the drywall and use homosote board as it has very good sound reduction properties. It's more expensive than drywall but then you want to be able to fix things to the wall anyways.

For the ceiling you could fur it out and use fibreglass insulation and then finish it off with 1/4 pegboard. The pegboard allows air in to add to the sound absorption.

For your floor I'd try those anti fatigue mats perhaps.

 

[Tinker]

Steve, I don't know a lot about sound reduction, I'll give you a few thoughts anyhow. First, I've never heard of 'Green Glue', so I can't offer any meaningful comment on the product. If you can afford to lose the space on the ceiling I'd really soundproof that as much as you can. I'd stay away from drywall and go with a drop ceiling, acoustical tile and insulation above that if you can. The wall that you share with the other unit must also be well insulated. Stand up a 2x4 wall, not touching the existing wall so not to transmit the sound (as much). Fiberglass is pretty cheap compared to the products made specifically for soundproofing. But fiberglass is really only so-so at soundproofing. As for the ducts, insulated metal duct work could be the best option if you don't have room the round flexible duct. On the floor you could just put pad and carpet down. Of course the floor would have to be dry and you couldn't roll large tools around very well on carpet. A wooden floor would be my first choice, if you can swing it. Other members here can probably offer better advise, but this is my 2 cents worth.

I agree with Brice.  One way to reduce sound in the walls would be to make a double wall with a batten type insulation between the two walls.  the drop ceiling weith insulation and accustic tiles is a good one.  neoshed has suggested pegboard in the ceiling.  I don't know about the circulation value, but it is my guess (no disrespect) that is a great way to accumulate dust. 

i have a concrete floor with some slight moisture problems.  i just built a wood frame with treated 2x's, treated 1/2" ply scord over the 16" o/c framework and 1/2" a/c ply wood over that.  I then put down a cheap linoleum tile for a finish.  The original concrete is not very level, so I could have shimmed, but i didnot.  the finish floor is not very level, but for shop work, i use parallel & square.  so long as i pay attention to detail, i don't care how level my floor is.  For setting up the MFG, one of the legs is adjustable so i end up with a solid base to work from. 

others will come up with other ideas, I'm sure.  I do have a question> Is this a rental unit of some sort?  If so, you might be wise to discuss with LL before starting actual construction.
Tinker

 

[John Stevens]

Jay StPeter occasionally posts here.  Maybe he'll chime in, but if not, here's some info on how he soundproofed his workshop:
http://www.sawmillcreek.org/showthread.php?t=10597&page=2

Yup, I'm in awe.

Regards,

John

 

[brandon.nickel]

Steve,

This is a topic that has seen a massive amount of conversation over at the AVS Forum.  All of the techniques will be very similar.  The only difference is the frequency of your noise.  You've actually got it relatively easy because most of the noise related to woodworking is fairly high-frequency.  Stopping heavy home-theater bass is by far the hardest task.  Do a search of that forum on Green Glue and you'll get a week's worth of reading material.

As a point of reference, I have Green Glue under my hardwood floor in my kitchen and between the double stud-walls separating our living room and master bedroom.  I feel that it has been effective, but it's rather expensive, as I'm sure you know if you've heard of it.  I actually have in-wall speakers in that wall about 2 feet from our headboard and we get much more sound through our doorway than through the wall.  I'm planning to replace it with an exterior grade (solid with weatherstrip) to fix it.

Two avenues are used here:  mass and isolation.  All of the fanciness in the world won't get you around these two principles.  The goal is to decouple the sound by making very heavy surfaces which don't want to move and separating those surfaces so that they cannot conduct from one to the next.  Research has shown that using two stud walls separated by an air gap with double (Green-glued) 5/8" drywall on one side and single 5/8" on the other is a highly effective method of reducing transmission.  You use different thicknesses because you want the resonant frequencies of the walls to be different.  Otherwise they can excite each other.  However, putting a good heavy wall around the perimeter of your room just reduces the transmission into your water tank (a great source of mass) and the basement walls.  Plus, you'd eat up a lot of otherwise useful space.  Double stud walls and 5/8" rock = 12" thick...

Your biggest problem is going to be the ceiling.  Options here include filling the joist space with a sound-absorbing batting (rock-wool works better than fiberglass) and hanging MLV or Green Glue-d drywall on RSIC bars attached to the ceiling joists.  For the floor, they sell isolation pads that you can set a floating floor on. 

So, it really comes down to the amount of isolation that you're hoping to achieve and the expense you're willing to go to achieve it.  If you're going for the ultimate you start to run into HVAC and electrical problems because you have to start sealing every penetration.  Acoustical baffles for HVAC are expensive and very restrictive to flow.  Sealing every hole and every wallbox with Green Glue starts getting exorbitantly expensive.

That probably didn't help.  If you want more, let me know.  People tell me I'm full of it.

 

[neoshed]

Acutally yes the pegboard would probably collect dust but I'm not sure how much. An alternative would be to use the Homosote on the ceiling as well.

 

[Lancashire Fusilier]

For the floor I will be using this stuff in my shop here in Australia. I am sure there is similar in the US.
http://www.ecotile.com.au/colour_textures.htm

 

[SteveD]

Thanks for the comments so far. I am also doing other off line and internet enquiries here.
The general consensus here appears to be:
Plaster (cement & sand) all the block walls to seal them tightly and seal the holes on the underside of the ribbed steel decking, either with mortar or foam (or both). That will take care of the direct airborne sound. Then seal the plaster (for damp proofing) with a suitable waterproofing sealer (cement or latex base).
This will leave a smoothish flat surface that should be coated with something either painted on or stuck on to reduce the sound transmission via the flat wall.
Then build 2x4 stud walls with studs on 24" centres an inch or so away from the walls with caulking or green glue on the bottom plate. As this is going on bare concrete, below grade, then perhaps use pressure treated wood.
Now there was an interesting suggestion for wiring. Put a strip of MDF about 12" - 18" wide around the room at the appropriate height and install all the wiring (in flexible conduit) and outlets. Then seal these against airborne noise using whatever is appropriate (e.g. canned foam). The advantage is that one can get behind the panel to do this whilst constructing.
Install heavy insulating batting between the studs and ensure it won't slip down.
Line the remaining area of walls with MDF sheets horizontal, screwed to the studs. Seal the gaps with caulking. It was also suggested to put inserts of 2x4 where the horizontal joins are, either flat or on edge. One could also coat the backs of the MDF with a sound absorbing paint/surface as they are hard and sound reflective.

Then use Green Glue and screws to attach vertically aligned drywall sheets to the MDF. This will require pre-cutting of holes in the drywall for the outlets. I have been reading interesting reports about the performance of this (and similar) products.
Finish (tape/mud) off the drywall as normal. Caulk the bottoms.

The ceiling  gives rise to some interesting challenges. The suggestions include coating/spraying the steel deck with something that is sound absorbing or helps to dissipate sound and will also help prevent condensation forming. (We get high humidity for several months each year). Then anything that will decouple the room ceiling from the floor above will help. Given that there is not much room to play with and a span of 15' is needed, I am still working on the best options. However it too will be sealed (surface mounted or sealed recessed lighting). This is also a good place to put some interior sound absorption such as Homosote or acoustic tiles to reduce sound reflection in the room itself.

The ventilation will be via 4" flexible insulated ducts that have a run and a corner. They should also be padded with batting to damp any vibration. There should be easily accessible dust filters and any fans (probably just an extract fan) on the start of the run rather than the end. The outside ends will be plastic, pointed down to the ground and it was also suggested that there be suitable baffles in the area. Apparently a vent pointing straight out on from a solid flat wall can act a bit like a loud speaker!

Also to be considered are venting for the space between the stud walls and the block walls. As one wall is a block built water tank and half the room is below ground level I need to ensure that there is some ventilation in the space.

The floor is currently not level or flat (the decking roof also slopes). Floating the floor off with a self leveling compound is needed, probably before the stud walls are built. I had not considered the linked tiles (thanks to the Lancs Fusilier) which will float on the floor, are replaceable, and do not require to be stuck down. That is a very good idea. Has anyone seen the equivalent in the US in hard vinyl interlocking tiles?

The main disadvantage of all the above is cost in both money and time. As I work alone most of the time I will need to get help for the MDF and drywall delivery and installation. Every additional feature from the stud wall through MDF, drywall and Green Glue adds to the cost and I will need to balance it all out. The room will still finish up basically square which is not the best for sound reduction. Not much I can do about that.

Advantages: nothing too complex. The MDF behind the drywall means I can mount cupboards or benches to the walls easily. Work surfaces attached to the wall may transmit sound directly to the wall and cupboards can create a resonance. Trade offs.

However all in all this has given me a better feel for the requirements, the challenges and a range of solutions I had not thought of.

SteveD

 

[Lancashire Fusilier]

Well the floor tiles aren't too much. I was quoted AU$55 per square metre plus delivery as a guide.

 

[gkeas]

I'm a home electronics designer/installer.

The most effective methods for sound reduction are:

Box in a box.  Don't let the studs or ceiling joists contact the studs of adjacent walls or the floor joists above.

Heavy fiberglass insulation.

Quietrock (super dense, super heavy sheetrock) Expensive, but very high STC reduction

Soundboard between layers of sheetrock

Z channel for the ceiling (acts as suspension for the sheetrock, reducing the transmission of sound through the studs/joists into the adjacent walls)

The sounds of sawing are definitely going to be easier to isolate than the sounds of subwoofers.

Also, if possible, use a sound proof door (or really heavy wood door) with a seal around it.

 

[Dave Ronyak]

I concur with Brandon that mineral wool (rock wool) is more effective than fiberglass in reducing sound transmission.  Mineral wool has a greater mass per unit of volume.

Dave R.

 

[Anthony]

For the floor I will be using this stuff in my shop here in Australia. I am sure there is similar in the US.
http://www.ecotile.com.au/colour_textures.htm

Hi LF. If you end up going for the EcoTiles, I am keen to hear what you think about them... installation, comfort, wear and tear. I have been contemplating them for our warehouse floor.

I can just imaging running them over the CMF or cutting them on the MFT, when they need to be trimmed around obstacles. Hey, why not route a round-over or bevel for fun. 

 

[JayStPeter]

I haven't been around here as much lately, but thanks for the mention John.  After all my research, I think Garry is spot on.  You need to isolate to keep the sound in your shop.  I didn't do anything to prevent the reflective sound within my shop as any sound reflected isn't getting out.  Anything you solidly attach to a floor joist or outside wall is going to transmit sound.  I found that the most cost practical materials were drywall and insulation.  But homosote is right there also.  In fact, homosote and drywall have slightly different filtering/absorption properties, so using them together on a single wall is of more value than two layers of one or the other.  Cost and effort will factor into your decisions as you go, so come up with a strategy you can live with.  Just using the methods in the link John provided is more than enough to allow my family to sleep upstairs while I work away in the basement.  The planer is the biggest problem, but using routers, saws, etc. are no problem at all.  From directly above the shop, it sounds like someone way down the street is doing some work on their house.  On the second floor it's barely noticeable.
soundproofing.org is a good place to start.  But, be aware that most of the sites that provide soundproofing information also sell stuff.  So, take what they say with some cynicism.  I also talked to some high-end contractors who do theater and music studio work (happened to bump into them at a party while planning my basement shop) and they kept me away from expensive stuff saying that isolation is the key for preventing sound transmission.  After isolation, drywall/homosote, and insulation it just gets more expensive for less gain.  Also, if you have a door from upstairs to the basement make it solid core.  It was enough of an expense as it was, so no more for me.
I would avoid the use of perf board.  It's more effective than nothing, but less effective than homosote or drywall since it has tons of little holes for noise to get through.  One of the contractors said it is effective at reducing reflected noise inside the room, but not as good as other materials for reducing transmitted noise.  I did the inside of my DC closet with it, but only because I wanted the perfboard walls to hang stuff on and one layer of drywall along with insulation is more than enough to keep the DC noise down (until you open a blast gate and the noise in the ductwork kicks up anyway).
For vents, to keep noise down in the vents you need to provide a path for air, but not sound.  So you have to baffle them.  Hopefully this little drawing will align right

    -------------------------------
Vent    |      Air source
          |
  |      |      |
  |      |      |
  |      |      |
  |            |
  |            |
  -----------

I also found that using insulated round duct and creating an S shape with it was pretty effective. 

Jay

 

[Lancashire Fusilier]

Hi LF. If you end up going for the EcoTiles, I am keen to hear what you think about them... installation, comfort, wear and tear. I have been contemplating them for our warehouse floor.

I can just imaging running them over the CMF or cutting them on the MFT, when they need to be trimmed around obstacles. Hey, why not route a round-over or bevel for fun. 

Yeah, they definitely look the business too. You will see them used in hardware stores by Bosch of all brands in front of their power tools stand. They have the name Bosch in the tiles. I asked them about that and he said he would screen print any logo onto any number of the tiles I wanted. Not prizes for guessing what I might get put in green letters on grey tiles on my floor hey!

 

[Anthony]

Hi LF. If you end up going for the EcoTiles, I am keen to hear what you think about them... installation, comfort, wear and tear. I have been contemplating them for our warehouse floor.

I can just imaging running them over the CMF or cutting them on the MFT, when they need to be trimmed around obstacles. Hey, why not route a round-over or bevel for fun. 

Yeah, they definitely look the business too. You will see them used in hardware stores by Bosch of all brands in front of their power tools stand. They have the name Bosch in the tiles. I asked them about that and he said he would screen print any logo onto any number of the tiles I wanted. Not prizes for guessing what I might get put in green letters on grey tiles on my floor hey!

What... "Bosch"?

 

[Ned]

Festool-labeled Ecotiles are not screen printed, they are molded in a two-step process where the green letters are cast first and then surrounded by the charcoal body of the tile--the color goes all the way through.

This results in a tile that will last 10 times longer than mere screen printing, and costs only 4 times as much.

And probably needs to be broken in.

;D

Ned

 

[Lancashire Fusilier]

Interesting you say that because I asked specifically that question about the Bosch tiles that ecotile had done and he said they were printed. I guess I could always buy a couple of green tiles and cut out the letters and corresponding hole in the grey...