Can I float a floor after wall construction is finished

JohnGardner · Post by **JohnGardner** » Wed Jul 21, 2004 9:20 am

As the question says, I know it's not ideal but:

Can I build the live room studio walls and ceiling, check for isolation in the control room and outside and if I,m not happy with the result, then float a floor?

The walls will be built on rubber feet to help transmission loss from the existing floor into the walls and control room.

The problem is the existing floor has about a 1foot gap to the ground (built on piles) and I am worried about sound loss through the floor to the outside world.

Thanks again

JohnG :?:

Innovations · Post by **Innovations** » Wed Jul 21, 2004 9:55 am

Well, I could see how it could work physically, you would have a gap between your floating floor and the wall that you would caulk.

But I am not sure it would work accoustically. When you float a floor, and then build the inner wall on the floor, you have also floated the inner wall from the floor. You will not have done that here. Sound that hits the wall would have a direct path to the unfloated floor. Similary vibrations in the unfloated floor could transmit up the wall and then into the room.

dymaxian · Post by **dymaxian** » Wed Jul 21, 2004 11:14 pm

If you're building those walls on rubber pads, that'll keep the walls isolated, as you mention. What you're suggesting will work, but it'll be pretty labor intensive- mainly just because of the PITA it'll be to get the floating floor cut just right to fit up to your walls snugly enough for a bead of caulk. It can be done tho.

IMHO you should spare yourself the trouble and just float it. If you believe there's a good chance that you'll need that kind of isolation, just err on the side of caution and be done with worrying about it. Better to know you went a little farther than to look back and wish you had.

Post by **Aaronw** » Thu Jul 22, 2004 12:13 am

Be sure to use a perimeter board. This will help decouple it from the walls.

knightfly · Post by **knightfly** » Thu Jul 22, 2004 7:51 am

If your existing floor has only one leaf of mass, there is absolutely no question that you will leak sound like a sieve out that floor - the same physics apply to floors as to doors, walls, windows, etc - two leaves of mass, one air(insulation) space between. Your existing construction sounds like just one mass leaf on the floor as you describe it.

If you used resilient channel on your inner wall leaf, you've already decoupled those walls from structure - if not, they would perform better sitting on a floated floor. However, the pads you used under the frame will definitely help.

And yes, you can do the floor after the fact - as Aaron pointed out, it will be a bit tricky to maintain decoupling between walls and floor, but doable.

What you need in EVERY direction, is a mass-air-mass barrier between you and unwanted sound - more mass per leaf, differences in leaves, wider air gap, hermetic sealing, all make for better performance - the main difference would be your surroundings; if they are quiet (and un-populated) you will need less isolation - if you lived in the middle of nowhere, and there were not even animals around making noises, a TENT would be your best choice since all you'd need is to keep the weather off your gear.

For more realistic situations, the degree of isolation needed is a variable that can only be determined by being there and taking lots of measurements; otherwise, overkill is preferred to underkill if you only have one chance... Steve