Noise-reducing Advice Needed

[Justin Smale]

I'm rebuilding my garage to include a rental suite along with a double garage, with the garage being mostly dedicated to gym space. I've had my equipment in my basement and been able to train mostly ok (ceiling height was a limiting factor) so I'm pretty pumped to get a new space. I'm in Canada and the garage is detached, but I'll be installing in floor heating in the slab to be able to train year round (I have trained through -30C outdoors in my first year of barbell training, I want a warm space now).

My issues are noise for the suite and potential damage to concrete from cleans/deadlifts. With the heating lines running in the slab (which will be a new pour), I don't want to damage the concrete and mess up that system - but I'm also pretty positive that the weight required to do that kind of damage is FAR beyond what I'll ever get to. I plan on building the AoM platform or something like that, so I'm guessing I'll be ok with those 2 layers of MDF and a horse stall mat, but does anyone out there have experience with this?

The other main issues is noise. I'm going to do all I can to limit the amount of noise transfer between the garage and the suite (i.e. double walls, rock wool insulation, etc) but I'm curious what other folks have done to limit the amount of noise transfer from their home gyms while deadlifting/cleaning.

[Mark Rippetoe]

The noise will always be there, get used to the idea. Pour a 6-inch slab instead of 4, use 1/2" rebar on a 12" grid, make the mud good 5-sack mud, and you should be okay forever. My platforms are all 3-layer MDF with rubber on that.

[badLifter]

Your problem isn't just 'noise', it's mostly shock: a bunch of low-frequency energy specifically.

A traditional deadlift platform, built of MDF and solid rubber, disperses this shock across a large surface area to protect your floor better, and does a great job of this, but also somewhat amplifies this shock. What you need instead is absorption, and that's really best done by soft material with lots of air pockets inside.

What I did to fight this was build a chambered platform: it's comprised of 3 sections that are 100x100 cms each. The centre one is just plain rubber; you can build this out of MDF, if you'd like. The other two are layered polypress foam with rubber on top. The sections are 15 cms tall each. This is essentially the same design as Eleiko's 'quiet' SVR platforms, that they sell for about 6,000 USD each.

My acoustic measurements showed a drastic reduction in low frequency. Anecdotally, I also no longer get complaints from my wife or the neighbours, even when doing sets of 10 on the deadlift.

[Justin Smale]

Thanks folks! Rip I misspoke, my slab will actually be 6" (I'm not doing the concrete myself) so I should be good on that front. Is there any advantage to MDF vs plywood for this aside from cost?

[Mark Rippetoe]

MDF doesn't "dish" on the floor. It lays perfectly flat with no need to periodically flip it over.

[WFB]

Noise can be transmitted through solid objects, so if the suite is next to the gym, I would build two stud walls out of 2x4 that don't touch. Stagger the studs so you can weave the insulation through and double-rocking both sides is a good idea. This will mitigate the amount of noise being transferred from one room to the next. If they are above you, you'll want to insulate between the joists, and then install independent framing for the drywall ceiling. If you want to go belts and suspenders, double-rock that, install furring strips and then double-rock again. I had to build a school that had a music room above a pre-k room (where naps were still part of the daily activity) and this was the detail to meet the STC rating.

[Mark Rippetoe]

If the slabs are in contact, the noise will make it into the other area.

[WFB]

You’re right and I thought about that after I hit send. Since the slab is new, he could put 2” rigid board insulation between the two areas to help isolate the noise. My suggestion above and this will help mitigate but not eliminate sound transfer.

[bikesandcars]

Using MDF / Plywood under "stall mats" doesn't really make it quiet, it mainly protects the floor. I have bumper plates and I think they are quieter dropping directly on my 6" concrete slab than on my lifting platform (think dead blow hammer on concrete vs on a sheet of plywood). So maybe think bumper plates? You can add some crash pads underneath (2" foam).

check these out, maybe less overall budget hit than complicated room construction: Buy Bumper Plates Sets | Vulcan Alpha Plates for Outdoor/Indoor Use

It's not just dropping weights, you didn't mention your music preference, but if you like to rock out to music, work on your car, play drums, or whatever else and have tenants some basic sound proofing is still in order.

The basic concept of soundproofing between rooms is to decouple and absorb. To the extent possible you want to have the walls between the spaces separated so sound doesn't travel through the materials and where possible to use insulation or materials that absorb sound in the ranges you are worried about. There are many many products out there from cheap to $$$

If you want to keep the walls / ceiling simple you could: : Rock wool (for mass and absorption) between the joists / studs and install the sheetrock with acoustic sealant . You could start there and if that's not enough you could add another layer of sheetrock with sealant between. Another method would be to sheetrock the ceiling using acoustic sealant as before, then hang a suspended ceiling under it with sound absorbing panels.

[bobman]

Buy the guy a copy of SS and Get the guy renting to do Starting strength and become a workout partner

Problem solved

If he’s older give him a copy of barbell prescription