To Float Your Walls Or Not? - Soundproof Wall Design

concrete slab existing floors floating floor floating walls nd isolator clip polyurethane foam rebond foam rockwool May 13, 2024

Do you need to float your soundproof walls or can they sit on the existing floor? In this article we will go over when you need to float your walls and when you don't. I will also cover some basic techniques on how to float a wall.

1) When do you need to float your walls?

Most of the time I try not to float walls in my designs. The reason is that it adds more cost and time to the build. However, there are times when you should float your walls. When you build on any floor that is not heavy concrete you must float the floor and probably should float your walls as well. This is especially true if you are building on the second story of a house and your walls would be connected directly to the rest of the home if you did not float them.

One of the major aspects of sound isolation is reducing or eliminating flanking paths. This is where sound travels from one material to another and eventually into your room When wood walls touch a wood floor the sound easily travels from the floor to the wall and into your studio.

So how do you fix this problem?

2) How To Float A Soundproof Wall (Overview)

There are two main options when floating walls. One is to use special acoustic isolators under the wall that decouple the wall from the floor and the other is to use common materials like neoprene rubber, or mineral wool to float the wall.

Rod Gervais, in his book "Home Recording Studio, Build it like the Pros recommends using ND Isolators from Mason Industries. (Gervais, 276)

example of Mason Industries ND Isolator

To buy the correct isolator you need to know the load of your floating wall. First, you need to calculate the weight of all the lumber, drywall, doors and windows in your wall and then you can purchase the correct isolator for the wall. This is not a fun task, but can be done by diagraming out your wall design on paper or in a CAD program and adding up the weight of each material.

If you are using mineral wool, rubber or an isolation pad you still need to know the how much weight the spring can handle. If the mineral wool for example is not dense enough then the wall may compress the mineral wool too much leading to less isolation. If the mineral wool is too dense the wall may not compress the wool enough leading to more sound transfer. Ideally, the mineral wool would compress about 50% creating an equilibrium where the force exerted down is equal to the elastic force of the wool leading to the best isolation possible.

You might be wondering, how do I figure all this out. The answer is either through the manufacturer's manual, such is the case with the ND Isolators or by using techniques that have proven functional. In the second case you would have to find charts showing the percent compression of the product with different weights added on top of it. As you can see all of this is fairly complicated, but it is an option. My point here is to not teach how to float a wall in depth, but more so, show you what is technically possible.

3) When You Don't Need To Float A Wall

When you are building on a concrete slab in a garage, basement or new building you do not need to float your walls or your floor. Concrete on earth is a great isolator and for most home studios, home theaters or offices will work perfectly as your isolation system for the floor. The only reason you may still want to float a wall on concrete is if lots of sound is traveling through the concrete floor.

Say for example, your studio is built on a concrete slab shared with a car mechanic shop. The shop would be driving cars on the slab, dropping tools, running heavy machinery on the slab and all those vibrations could travel through the slab into your studio. In this case, I would say don't build a studio there, but if you had to you would want to float your walls and floor off the slab.

Conclusion

Now you know when you should and should not float a wall in your soundproof room. Remember, that you need to float walls if you are building on top of a wood deck in your home. Second, to float walls you can use isolators like the ND Isolators from Mason Industries or rubber, or mineral wool pads. Whatever you use to float your wall you want to make sure the isolator material can handle the weight of the wall.

Lastly, you do not need to float a wall if you are building on a concrete slab over earth. You can simply build your walls on the concrete and add a sill gasket for moisture, but you do not need to float the walls.

Works Cited

Gervais, Rod. Home Recording Studio: Build It Like The Pros. 2nd Edition, Course Technology Cengage Learning, 2011.

Mason-Ind.com, 2024, mason-ind.com/nd/. Accessed 9 May 2024.

Philip Richard Newell. Recording Studio Design. New York ; London, Routledge, Taylor & Francis Group, 2017.

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