what material would best dampen the noise and vibrations of a treadmill
April 12, 2012 8:47 AM   Subscribe

DIY Engineering filter: Help me be a better upstairs neighbor by selecting the best possible material to dampen the noise and vibrations from walking on a treadmill under a desk.

After playing around with a standing desk for awhile, I recently decided to take it one step further and purchased a specialty treadmill designed specifically for low-speed walking, and installed it under my desk. While the machine is not exactly whisper quiet, the sound it makes in my office is very tolerable. However, the vibrations are making quite a racket for my downstairs neighbors that I'd rather they didn't have to deal with.

We're on good terms with the folks that live below us, and we've already spoken about times when the noise would be and would not be a problem. But given that my intent is to (eventually) be walking on the treadmill for several hours each day, I'd like to do everything I can to reduce the noise and vibrations that travel downward. (I rent, so I can't make any changes to the floor itself)

The common wisdom on reducing treadmill noise seems to be that the best way to do this is to create a large dampener that spreads out the noise and vibrations over a wide area using two materials. On top, a strong and rigid material (like plywood) is used to spread out the weight. And on the bottom a springing absorbent layer is used to absorb the vibrations. This past weekend I purchased a very heavy piece of MDF board that's 3/4 of an inch thick and 78" by 28" (the treadmill is relatively small). But I need help figuring out which type of foam or product I should buy for the absorbent layer. As I see it, there are three basic requirements for this material:
  • It needs to absorb vibrations and sound as much as possible.
  • It needs to withstand some pretty significant downward physical pressure. There will be a constant weight of about 160 lbs (100 lbs from the treadmill plus 60 lbs for the MDF board) pushing down on it at all times. And then, once you add my weight when I'm walking on it, the downward pressure will be about 350 lbs.
  • It needs to retain its absorbing qualities over time as much as possible I would rather not have to replace the foam layer every six months because it flattened out.
Which gets me to my questions.
  1. What type of material should I buy? Rubber, soft foam, rigid foam insulation, or something else? Specific product recommendations are welcome.
  2. What is the relationship between the thickness of the foam and its effectiveness at dampening? If I were debating between buying foam that was half an inch thick, and 1 inch thick, how much would that extra thickness get me in terms of additional dampening effect? Is a 2 inch pad twice as good as a 1 inch pad, or some fractional proportion better?
Thanks in advance for your help!
posted by dyslexictraveler to Health & Fitness (11 answers total) 4 users marked this as a favorite
What you want is these neoprene rubber sound isolation pucks. You don't need a full layer under your plywood, just enough to support it, so maybe a grid every 18 inches. Or get the pad shown at the same link. Not cheap, but very effective. This material is used in industrial situations to isolate equipment from building structures and works better than anything else you're going to find.
posted by beagle at 9:02 AM on April 12, 2012 [1 favorite]

Lots of mass with any dense foam or rubber will work pretty well. A couple layers of sheetrock with green glue between and MDF on top would probably do the trick if it's cheaper than the aforementioned neoprene pucks.

I'm a cheapskate, so I'd probably first try an MDF sandwich of really dense foam, a few layers of carpet padding, or a even that "great stuff" foam.
posted by pjaust at 9:17 AM on April 12, 2012

Plywood + rubber horse stall mats. Total cost will probably be around $50.
posted by bfranklin at 9:18 AM on April 12, 2012

You might consider a memory foam mattress pad a few inches thick.

The density is very high and is an excellent energy absorber. It will probably the easiest thing to go look at in person before you buy and easiest to place under a plywood sheet.

Good luck! A friend uses a walking desk and loves it.
posted by Argyle at 9:36 AM on April 12, 2012

I would be tempted to try a simple sand box. Put some plywood on top of the sand and perhaps add the neoprene rubber sound isolation pucks mentioned above (I would use one at each corner/support feet of the treadmill).
posted by aroberge at 9:56 AM on April 12, 2012

I would say Memory foam pad is a great suggestion but be aware they will get dirty and cleaning is a bi***.
posted by radsqd at 11:09 AM on April 12, 2012

Also look for Subwoofer vibration isolation material , same premise as yours
posted by radsqd at 11:10 AM on April 12, 2012

I bought a 1 1/4 inch thick rubber mat (at Canal Street Foam & Rubber in NYC) for use with my electronic drumset in my apartment. That works for me.

Other electronic drummers (who are creating a similar racket as you with your treadmill) swear by the so-called "Tennis Ball Platform."
posted by monospace at 11:26 AM on April 12, 2012

You have any old blankets? I'd throw them under the MDF board and see how that works before I went off buying expensive specialty materials.
posted by exphysicist345 at 2:48 PM on April 12, 2012

Best answer: Those rubber isolation pucks work great, that is what they use in a lot of recording studios to keep sound from transferring through the floors from one room to another. The thing about them, though, is that you have to use the right amount for the weight they will be supporting.

To reduce the sound levels transferring to your floor, you want your material to act like a shock absorber. If it is under too much load, it won't work (imagine standing on a tiny spring, it will squish down all the way and not be springy any more). Alternatively, if it is not under enough load, it also will not work correctly (imagine you have a spring designed to hold up a car, and you are tapping in it lightly with a hammer. The spring won't be squishing down at all because there isn't enough force, so it will be acting like a rigid object and transferring the hammer blows to the surface below).

So, if you do decide to go the rubber puck route, make sure you talk to the person selling them to you and find out what their optimal operation load is, and buy accordingly.

With that being said, you are going to get some good results no matter what you do based on what you already know. A memory foam mattress will probably work great, although it might not feel stable enough underneath you when moving around (or it might just help you to work your core muscles a little more with the added vibrations). Anything used as a bed will probably work well considering the weight load you are putting on it, which is comparable to 2 adults.

The only thing that I would keep in mind is that if your floors squeak at all, or if there is any flex to them which may cause noise, try to keep your base as spread out on the floor as possible, since the weight on the treadmill will be shifting around, and depending on how you build your support, you may run into issues if you are putting all of that weight onto a small footprint. So, for example, if you do end up using the rubber pucks, and you only need 4 of them, rather than putting those on the floor, you might want to put an additional layer of plywood underneath. I know in my house the squeaks in the floors which sound very quiet upstairs sound extremely loud in the room below.
posted by markblasco at 9:57 PM on April 12, 2012

You sound like a conscientious neighbor. Good for you, dyslexictraveler!
posted by lovingkindness at 8:44 AM on April 13, 2012

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