# Workshop Soundproofing



## Scinzon (Apr 29, 2015)

Woodworking can be very loud. Even things that most people would deem "quiet", like carving and working with only hand tools are loud in reality.

Workshop Soundproofing is an issue that has buggered my mind since a long time ago and still does.
I have no workshop to begin with, but it is always nice to know and plan in advance. 

I live in a city; in Europe. We do not have car garages like people in America do. A two car garage here means that you are filthy rich and the government will tax you so much that it would be cheaper to rent a small space.

Anyway, I like working at night and I say this literal. I work from Dusk till Dawn. It is far, far, far better for shooting videos and even when I am not making videos I prefer to work at night because there is far less outside noise. 

So, if I ever get a workshop I am going to soundproof it. The idea is to keep at much noise and vibration inside. Preferably my workshop will be at ground floor or a basement in an apartment building.
Ideally, basement or ground floor, there will not be any residences above it, but this is a very long shot.

The question is, how do I do that without breaking the bank too much?

I can have all the loud tools in one room. No need to use ludicrous soundproofing for painting for example.


----------



## was2ndlast (Apr 11, 2014)

Soundproofing is quite hard to do well. Although I have not done it for my workshop (garage) I have done it for my home studio which included my drum set in my last home.

So first, if you don't want to spend a lot of money forget soundproofing....you will only be able to lower the dB that is heard outside your shop. Are you willing/able to build new walls or just treat an existing room?


----------



## Quo Fan (Feb 15, 2015)

To prevent sound transmission between walls, you need a disconnect between the exterior surfaces of the wall. One way you could do this is to build a wider wall, alternating studs to either side of the wall. Think a 6" wall, using 4" studs staggered to either side of the wall. Another way is to install a layer of Homasote under a layer of drywall. This is the easiest option, and doesn't require building a new stud wall.


----------



## Scinzon (Apr 29, 2015)

I can build brick walls, which here are considered "real" walls and require a study by an architect and a license, and I can also build "faux" walls, which are wood and Drywall (Plasterboard) and do not require any license because they can be counted as decorations. 

(My apologies to all American readers, but building codes here in Europe actually consider your walls to be only "fake" walls.  )

Yes, I have no illusions, I will need to dig deep into my pockets for that. I was wondering though if I can salvage soundproofing materials from nightclubs. Many open and close down a few months later and then the new owner wants to use them as something else and wants to get rid of 1-2 year old soundproofing materials so if I can go there and remove some I can get it for free. 
It is also worth to mention that these nightclubs are very often located directly under apartments so they have to have good soundproofing to keep the 120+ db music inside.

Soundproofing is probably not going to do much for hammer strokes, but it should work for Circular Saws, Band Saw, Drills, etc. My goal is to be able to work without my neighbors noticing it or at least to reduce the noise to below tolerable levels. That would be like a washing machine working in the apartment above you.


----------



## Improv (Aug 13, 2008)

Hang heavy curtains around the walls and ceiling. Rugs or soft anti-fatigue mats on the floor. Avoid having hard, large, flat surfaces.

Regards,
Steve


----------



## hwebb99 (Nov 27, 2012)

I have shot in two different indoor shooting ranges. One has foam on the walls. The other has nothing. The foam makes a HUGE difference. I don't even like to go to the other range because it is so loud. I'm not sure it makes much difference outside though.


----------



## was2ndlast (Apr 11, 2014)

hwebb99 said:


> I have shot in two different indoor shooting ranges. One has foam on the walls. The other has nothing. The foam makes a HUGE difference. I don't even like to go to the other range because it is so loud. I'm not sure it makes much difference outside though.


That's the difference of sound treatment vs soundproofing -very different. Treatment improves acoustics in the space, proofing prevents transmission. Quo is correct. The only way to soundproof is to disconnect. Many ways to do it and special drywall connectors but if you can build fake walls...essentially a room inside a room with air between the 2 that is most effective. Any solid surface to surface contact like a stud against drywall just transmits the sound. Beware of too good to be true products....there are soooo many snake oil solutions.


----------



## Chris A (Feb 9, 2016)

Scinzon said:


> ...
> The question is, how do I do that without breaking the bank too much?.


There really are only two ways sound moves out of the room

1) The sound pressure buses on a wall (or ceiling of floor) and causes it to move. The other side of the wall moves and then creates sound in the adjoining space.

2) There is an air passage. A crack under a door or even an open window or a heating duct. This gap, even if it is small is very effective in transmitting sound.

You have to address both. First make the room air tight. Use good weather stripping on all doors and windows and plug the holes around where plumbing comes in and around electrical outlets and ceiling lights. Find every last little hole and fill it.

As for walls, building one heart wall out of (say) bricks is not as effective as two lighter ones that are not mechanically coupled

Recording studios are the reverse problem. Keeping sound out. Many times that are built as a room within a room. They start with a much larger space then put rubber pads on the floor and then floor joists on the pads then build a wall a few feet inside the existing walls and a second ceiling below the existing ceiling. The inside room is minima coupled to the outside room. 

There are a few handbooks or tables you can read that give you sound attenuation numbers for each construction method. Some building codes requires some types of sound attenuation (shared walls in apartment buildings) There is no need to guess as you can look it up.

The first step is to measure the sound level in a typical shop. Then decide what is an acceptable level of noise at some distance outside of the shop. Now you have a NUMBER. the units will one dB (decibels) which this number consult the engineering handbook for a construction technique that has the required attenuation.


----------



## Scinzon (Apr 29, 2015)

99% Probability, the doors will need to be replaced. Most doors are just a pine frame with the thinnest possible plywood stapled on it. No problem there, I plan to fabricate more secure doors anyway. I also know someone who has a shop for that.

As for the room-within-a-room, this kinda sounds bit too extreme. The goal is to reduce the noise heard outside the shop to legally non-illegal levels. That would be like 65-75 db if you stand directly outside the door.

Homes here usually have two layers of (not solid) red brick with some Styrofoam shoved in between them. Each red brick layer is like 5 inches thick and the Styrofoam is like 2 inches. This is only basic insulation and you can hear two people having a normal conversation in the other room. 
A workshop that I will be able to rent (should be cheap  ) will most probably only have two layers of red bricks because this is how older buildings were made.

There is no need to extrapolate max db I believe. That would be 125 db (loudest tool I have is like 123 db). If I reduce that to 75 I will be very happy. As for vibration, I don't really do anything too "quaky". The most vibrating thing is my air-compressor which I will somehow silence.

I might also get a db meter soon. Does anyone have any experience with the cheap branded ones from Ebay?


----------



## hwebb99 (Nov 27, 2012)

If you have a smart phone you can download a decibel measuring app. Not sure how accurate they are.


----------



## Korosu (Oct 16, 2014)

I actually am in a similar situation. My wife and I just bought a townhouse back in September. I converted a room into my shop. I looked into acoustic foam. Not only is it hard to find but its also expensive. So I found a cheaper alternative. I went out and bought those foam mattress toppers and stapled them to the wall. They worked really really well. It's not
completely soundproof but no one can really tell when I'm making pens on the lathe.


----------



## difalkner (Nov 27, 2011)

While not true soundproofing I can tell you that when we insulated our attached two-car garage and garage door the sounds heard outside dropped drastically when running shop equipment like routers and table saw inside. I sometimes run tools well past 10 at night and have asked neighbors if they heard me and not once have they reported back that I was making too much noise. Matter of fact, most had no idea I was even in the shop unless they saw lights.


----------



## was2ndlast (Apr 11, 2014)

All sound is transmitted via vibration, not just quaky (low frequency) ones. The easiest to deal with are high frequencies due to their shorter wavelengths so examples as stated above will be able to absorb some of the energy of these so what is left transmitted out is lower energy (lower db) - thin foam pads, blankets etc can work here but limited. Don't think mass is an efficient way of soundproofing - the 12 inches of walls you mentioned didn't do much because it was all coupled.

1/2 inch of drywall followed by 6 inches of air will be more effective than 6 1/2 inches of drywall. 

For what you want to do, an idea could be to focus first on high transmission culprits - windows, doors, outlets, light fixtures in ceilings etc. All these have gaps for sounds to travel through. Seal it up with acoustical silicone and then hang some blankets on the walls. That's a cheap way to see if it gets to where you want to be.


----------



## Scinzon (Apr 29, 2015)

hwebb99 said:


> If you have a smart phone you can download a decibel measuring app. Not sure how accurate they are.


My phone is from 2005. 

As far as I know the Application works for measuring sound levels but it is not very good for measuring pressure; something like that.



I guess that "foam mattress topper" is just upholstery foam? There are many varieties of that. Some are very hard and heavy. I can get those in any size for "cheap" if they really do work. They can be glued with Contact Cement. 
Maybe these and Drywall will work even better?

Yes, I am not even aiming for complete soundproofing.I just want my neighbors to hear nothing or just a low noise that they will think that it is actually kitchen machines. 

I checked some charts last night. It seems that I overestimated the noise levels of my tools. According to the manuals, the loudest tool is my Nail Gun at 115 db. However, all these numbers are for sound levels when the tool is idle, so 125 db seems to be a good estimation.


----------



## difalkner (Nov 27, 2011)

115 and 125 seems awfully high for a nail gun. Miter saws are generally in the low 100's (100 to 104 or so). I would think a miter saw is much louder than a nail gun. A nail gun has the impulse short duration noise in the 'pop' but that still seems high.


Found this on another site -


----------



## Korosu (Oct 16, 2014)

It looks something along the lines of this. There are many variations of course.


----------



## Scinzon (Apr 29, 2015)

According to the manuals of my Mitre Saw: 
Sound Pressure Lpa: 99,4 db (uncertainty Kpa 3 db)
Sound Power Lwa: 112,6 db (uncertainty Kpa 3 db)

In Europe household electricity is 220V. Tri-Phase is 440V so maybe our "enthusiast" tools are as powerful as "professional" USA tools? There is also the Hz difference. Europe uses 50 Hz. 

It won't harm to exaggerate a little and go with 125 db. This is a 100% increase, I know, but in this case exaggerating is good; this means less noise for the neighbors. :thumbsup:


No idea if the upholstery shops carry this type of foam. I will have to inquire.


----------



## Gary Beasley (Jan 21, 2009)

Look for Roxul Acoustic insulation in your area. From what I've seen it is fire retardant as well as good at soaking up the noise.


----------



## Scinzon (Apr 29, 2015)

Went to Roxul website.

They asked me if I was a homeowner or architect or something like that and if I have Hispanic or Latino ancestry. xD

Anyway, there is not Roxul where I am, however, Roxul is part of Rockwool and there is Rockwool here. The page however does not appear to have an English version.

I love how there is no mention to decibels in the product PDFs.  I mean, you cares about decibels when shopping for sound insulation, right?


----------



## Chamfer (Sep 6, 2014)

I used to be a spray foam technician here in the US, have been in construction as a carpenter for a while and am a certified audio engineer, so please take this with a grain of salt.


I don't know if there are spray foam companies over there but if there are then ideally, if money is not an issue, I'd build false walls with a dropped ceiling just inside the existing walls/ceiling. Essentially a framed box that does not attach to the existing walls/ceiling. Fill that with open cell spray foam and finish your inside walls with something like Quiet Rock, which is a dry wall that is designed for sound containment.


----------



## Scinzon (Apr 29, 2015)

It is amazing how many options are available.

Searching for foam and stonewool I also came across this thing which is too good to be true, but I think it is worth mentioning.





Yes, a Google search revealed many local foam companies. However, I wonder how this foam compares to the other materials available. 

I prefer the choice of salvaging materials and reusing them myself because this will keep the costs down a bit and that bit can be invested in tools.


----------



## Chris A (Feb 9, 2016)

Scinzon said:


> ...
> I prefer the choice of salvaging materials and reusing them myself because this will keep the costs down a bit and that bit can be invested in tools.


Yes salvage and repurposed materials can work but YOU then must have the means to test them. Building are expensive and you need to engineer them to meet your requirements so then you know before you spend the money. You you'd need to measure the sound attenuation properties of an salvaged material before you go to the trouble of installing a literal truck load of the stuff. And YES, even for the small space you are taking about, you are going to need a good size truck to haul it all. Just work out the required cubic volume.

Again the best is to have zero physical connection between inner and outer surface AND to seal every space where air might flow. You will then need ventilation ducts with baffles. 

The lowest cost material you will find is normal fiber glass insulation, It works as well as the expensive stuff and is cheap.

Finally DO NOT GUESS. The data for sound attenuation is available. Pick one of the published designs.


----------



## Scinzon (Apr 29, 2015)

No problem with testing, I just need to get a db meter first.

I am aware of the volume of the matterial. This however would be trouble only if I salvage them, because I will need someone with a truck to help. Otherwise, 50€ shipping and most companies dispatch a truckload. add another 20€ for the transporter guys and we are fine.

Does the "Room Within A Room" method not require vacuum between the walls?

In any case, it is probably a little too extreme. My biggest concern is that the gap will be crawling with cockroaches within a few months...:icon_sad:
not to mention that the space will be reduced significantly.


----------



## Chamfer (Sep 6, 2014)

Scinzon said:


> In any case, it is probably a little too extreme. My biggest concern is that the gap will be crawling with cockroaches within a few months...:icon_sad:
> not to mention that the space will be reduced significantly.




If you use spray foam in between the walls there won't be anything in there. Rodents and insects do not like it. The same can not be said for fiber glass, rock wool or cellulose. 

The loss of space I wouldn't call significant. You could literally be an inch away from the existing walls/ceiling and lose less than a foot all around.


----------



## Chris A (Feb 9, 2016)

Chamfer said:


> If you use spray foam in between the walls there won't be anything in there. Rodents and insects do not like it. The same can not be said for fiber glass, rock wool or cellulose.
> 
> The loss of space I wouldn't call significant. You could literally be an inch away from the existing walls/ceiling and lose less than a foot all around.


Rigid foam would delete the purpose by mechanically connecting the two walls. Plus have you checked out the price of spray foam? Almost all of these just have air between the walls

Who asked about vacuum? Yes that would be perfect but the structural requirements would be horrifically expensive. The force on the walls from both sides would be just over 10,000 kilograms per square meter. from each side. The empty space would be crushed. Air works almost as well, use spray foam for sealing cracks and air for filling the larger spaces.

You need to read the link below then simply pick one of the STC levels.
https://en.wikipedia.org/wiki/Sound_transmission_class

Here is another one
http://www.audimutesoundproofing.com/how-are-stc-ratings-calculated.aspx

Just follow one of the well tested methods so you can predict the result with some level of confidence.


----------



## anilchandran (Nov 3, 2016)

in such a situation , best solution is to have a temporary sound proof wall, but for effective sound proof it is better to go for layer by layer tempory wall, or curtain for example, i recomment to go through this article www.soundbarrierfence.com/…/und-Barrier-Insulation.html and www.soundbarrierfence.com/…/f-Fencing-Introduction.html
look how 4 layer sound reduction is used to make a sound proof fence. and better part is its easy to remove and transport. i hope it is helpful for all


----------

