How to soundproof the Wood Shop?

Question

I hold a small (15qm) Wood Shop at the basement, where I have the classic power tools like: a miter saw, a bench saw and a wood drill press and some other hand power tools.

There is a real issue with the noise, the power tools are too loud and the neighbors are irritated.

Now I was looking into tools that are silent, but since they are expensive and hard to find, and I think it would be easier to soundproof the whole room or put the tools in a soundproof box.

My loudest tool has 108db(A) and produces frequencies from 400Hz to 16kHz, for that I have considered using inflammable resistant acoustic foam. But before I start spending money, time and research, I wish to ask first :

Have any of you had to soundproof a wood shop? what solution is effective if so?

Answer 1

I know this is late, but I have a lot of experience to share on the topic. I have a 12 x 14 basement shop(actually has a pullout sofa taking up valuable space) and neighbors who complain about EVERYTHING. The problem is the neighbor doesn’t just complain, they rally other neighbors to generate a consensus anytime they have a problem with my existence. I’m an affable guy who volunteers to improve my neighborly duties and ask for open dialogue should anyone have an issue. Still, they ignore this and once a year gang up on me with a complaint or two.

Basement tool noise will NOT be the next issue! I don’t have a fancy space at all. I have stones set into concrete as a floor (60s style), a drop ceiling and drywall. The outside walls are cinder blocks covered by super thing sheetrock. There is one small basement window just at ground level and it has an aluminum retaining ring just outside the window.

As you can imagine, the window is a big amplifier of noise. It will rattle and vibrate when sound waves hit it and the aluminum retaining ring outside acts like a steel drum to direct sound up against my siding and against the neighbors wooden fence. The first thing to do is make sure I limit the magnification of sound waves in the shop. High frequency tools in high decibel ranges will create aggressive sound waves (like VVVVVVV as opposed to ~~~~~~). So the first thing I recommend everyone doing is cover your shop floor in mass loaded vinyl sheeting. It’s not cheap, but a lot of shop noise comes from bouncing waves off concrete floors or wooden echo chambers built on concrete. Laying mass loaded vinyl and then ideally another rubber or vinyl floor surface for cleaning ease and comfort. This will already dull the cacophony of sound in a small shop. Next put an anti-vibration pad under your machines when possible, including those on your benches. It makes a 3-5 decibel difference with most setups. Next, this part depends on how quiet you want your setup and what you can afford to do.

I like to work in the shop late at night. It’s a therapeutic activity for anyone who can’t sleep well due to PTSD or whatever. I lined my ceiling and walls with Dekiru Hexagonal acoustic panels. They look great and you can make some impressive designs. It’s pretty awesome when your shop looks like a recording studio or a high-end YouTube channel. What is even better is the quietness of it. Your tools are still loud and you still need to wear ear protection! But outside of the shop is muffled very much, to the point that my wife sleeps soundly directly above my shop while I’m using a table saw and running dust collectors.

A detail on windows, doors and dust. I made a hinged drop-down soundproof cover for my window for when I’m working at night. During the day I don’t worry about it unless the neighbor has a pool party going. Hollow doors are basically speakers for your tools. If you have a hollow door you need a sound deadening blanket (film/Hollywood studio blankets are $30-40) to hang over the inside of the door. If you put your dust collector in a closet, which I recommend, line the closet and the door on both sides with acoustic panels. You need a vent cut into the door or closet, but use acoustic sealant around the vent/register. I also like to make an angled hood to direct the sound and air down as it exits or enters the closet. I just use foam core hobby board and sealant to make this deflector.

Without these measures, your tools work in concert to create chaotic and aggressive frequencies which have multiplied from the origins at the tools themselves. As they bounce around they increase upon impacting each other with greater and greater frequency(more often). By adding the mass loaded vinyl on the floor and acoustic panels around the room, the waves are partially absorbed or retarded before continuing on their journey. This keeps the sound from getting out of control. My shop is at 71 decibels with a 1.5hp dust collector in the closet, a WEN air filtration unit hanging above my head, and one tool running. I COULD skip hearing protection for most tools (some run at 95-100 decibels, like a table saw) but it’s still not pleasant.

My final recommendation is buy a quality set of Bluetooth hearing protection. IsoTunes Link 2.0 is fantastic with the addition of a boom microphone option. It lowers shop sound by 25 decibels and can play your music, podcast, YouTube instructional video, or phone call. The mic actually cuts high frequency shop noise and boosts your voice pretty well. I just had a phone call with my boss while using a power sander. They also make a smaller earbud style if you prefer or are wearing a full head mask. It’s the IsoTunes Pro 2.0, and it’s a few bucks more. It’s also 2dba quieter to boot!

For those curious, 3 feet from my closed shop door reads 44 dba while I’m running my table saw. My furnace is louder than that.

Good luck to you all. Just make sure your dust collection is excellent if your are sealing your studio for sound. Make sure those air filtration units and dust collectors are on timers and run for at least 30 mins after you leave. It takes 30 minutes for 2 micron dust particles to settle to the floor.

Answer 2

The advice for a shop is pretty much the same as for any loud activity. There is a lot of research you can do on the internet for music studios, for example, that will apply. So, this is not specific to woodworking¹.

The first question is what is your budget and how much work do you want to do? Ideally you would physically separate the walls from the floor, and the ceiling from the walls. This is a pretty tall order, though.

The most important thing to do is block as much air movement between the inside and the outside. Then you install sound blocking material between the basement and the rest of the house. The notion is that there is no single magic bullet; the only real solution is mitigation in depth by using multiple sound mitigation techniques together.

A serious modest approach would be something like:

• Clear all your tools from the walls and remove everything covering the walls and ceiling.
• Buy a case or three of acoustic sealant, and fill every crack and hole that allows air movement between the shop and the rest of the world. You cannot overdo this step, and no hole or void is too small to consider.
• Buy lots of sound insulation batts, or hire a firm to install blown or spray insulation into all the voids, making sure to get into every corner and nook.
• Cover with sound block rating wall covering of some sort, making sure to (in most cases) use multiple layers and follow the installation process for overlaps, joins, and things like outlets and light switches.
• Replace all doors and windows if necessary, and replace the air-seal around them.

You will probably have to separate the HVAC systems so the shop has its own heating and cooling, unless the rest of the house is ok with the sound coming through hot or cold air ducts. If you have non-ducted heating/cooling you already have a head-start.

A non-modest approach is to do all that, but start by building floating stud walls and ceiling that decouples the interior walls from the outside as much as possible, including (ideally) installing a floating floor.

A cheap-and-cheerful approach is to air-seal as best you can, and then use two layers of drywall, installing acoustically rated batt insulation in any significant voids. Seal the doors and windows (or cover them in semi-permanent baffling) and either put up with sound going through the ducts, or stuff them with some sort of safe baffling while you are in the shop.

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¹ That being said, I think wood shops are easier for sound management because at least we don't have to deal with as many high-energy low frequencies. This means that full surface separation as discussed is probably not strictly necessary except in the most specific cases.

Answer 3

The answer provided by jdv is excellent advice and addresses sound transmission through air. Plus, as i mentioned in a comment, the mass of masonry walls and the earth will eliminate most sound transmission below grade. There may also be structural transmission to consider. If you have an interior surface that directly contacts the structural wall then sound vibrations will also be absorbed by the interior surface and transmitted through the studs or masonry. If there is exterior masonry walls, then the mass of the wall should be adequate to absorb shop sound. If it is studs then the sound may be traveling through the structure. The only way to significantly reduce that noise is to provide a second wall surface on the interior that is independent of the exterior wall. It should be have minimum contact with the exterior wall and be filled with insulation to reduce air transmission.

But something sounds a bit peculiar. I would expect that conventional wood framing (or masonry) of an exterior wall should be adequate to eliminate most noise in a short distance from your home. It sounds like there could be a duct or other opening venting to the outside that is allowing more direct travel for the sound.