How To Build A Plywood Soundproof Floating Floor
Dec 26, 2022For some reason one of the first things people think of when they hear the word soundproof is: floating floor. Now you can float a floor to build a soundproof recording studio, but honestly it is not the best method.
In this article I will go over why a concrete slab is better than a floating floor and I will teach you a simple way to build a floating floor in your studio if you really think it the best option for you.
Why A Concrete Slab Is The Best Soundproof Floor
Contrary to that popular opinion about floating floors, it is actually not the best option for a recording studio The reason is that you need mass to stop low frequency sounds from kick drums, bass amps and subwoofers A floating floor simply does not have enough mass to stop those low frequencies.
It is good at decoupling your floor from the rest of your structure and in that case it is a great option if you absolutely cannot build on a concrete slab.
The best way to build a soundproof studio is to either pour a slab in your backyard, build in an existing basement with a concrete slab or build in an existing garage with a concrete slab.
So definitely start with a concrete slab before you go about floating a floor if possible.
How To Build A Plywood Floating Floor
1) Use Iso-Pads to decouple the floor joists
To start with you are going to lay down several "sleeper boards" on your existing floor. These should be 2x4's placed every 16-24" OC depending on your building codes. You need to have iso-pads under the 2x4's so that you don't get sound transfer through the wood joists.
To do this, I recommend buying Iso-Track Stud and Joist Isolators from Sound Away. These pads will do the job of isolating your 2x4 floor joists. You simply place the 2" side into the U-shaped pad and let it sit on your existing floor. That is it.
2) Next, add low density fiberglass between your studs.
Between your floor boards add low density fiberglass like Owens Corning 703 2" thickness between all of your 2x4's and iso pads. This will absorb sound that passes through the floor by turning it into heat. This is the same way acoustic panels work as well.
3) Add a perimeter board around your room
You can see in the diagram below that you need to add a board that will separate your plywood floor and the existing wall. Place this board all the way around your room before adding the plywood.
4) Add two layers of plywood to your wood nailers on your iso pads.
Next screw your two layers of plywood to the wood nailers or "sleeper boards." Make sure to switch the direction of the plywood for the second layer so your seams don't overlap. You could add a layer of green glue between your two plywood layers for added soundproofing. See the image below from "Master Handbook Of Acoustics."
5) Caulk around the edges where the plywood and perimeter board meet
This will ensure that you have an airtight seal and no sound will come up through your floating floor.
6) Add your final finished floor on top of the plywood
I used engineered hardwood, but you could use hardwood or laminate flooring as well. A carpet may help with some impact noise and reflection in your room.
That is really the whole process. The key is to make sure you follow every step precisely and not forget to caulk your seams. If you are building on top of an existing floor that is not a concrete slab then this method will work to reduce sound coming through your floor.
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