Floating floor design - Polystyrene?

[sebring]

Hi, I just found this post and thought I'd try to get some of your ideas on my studio construction.

Background in a nutshell:
3 1/2 years ago I built a (one) room within a room in a detached garage, ~20x15. I built the whole room on top of 8'x8' x2" polystyrene covered with 5/8" tongue in groove floor board. Small gaps between the polystyrene (1/2"). The floorboard is held together by the wall framing, nailed to the floorboard.

Now, I figured that the polystyrene would compress some and then hold, but wasn't real sure. I talked to two different contractors that gave me conflicting answers, but I think that as it compresses over time, it will have more resistance (to compression) as well (resulting in less sound insulation) but for the most part, I think it will last. The floor is a little bowed in the middle (weight form the structure and equipment on the outside walls), but slightly, and no one ever notices it.

Questions:
1. Will the polystyrene hold up?
2. Will the floor bubble in the middle to a ridiculous degree?
3. What are the benefits of the floor being raised on posts and Neoprene pucks vs the whole floor covered with Neoprene and the floor lying flat on top (besides cost)?

On the whole it has been a success in terms of protecting the neighbors and it’s a quiet, good sounding room.

Thanks!
mike

[knightfly]

Hi Mike, and again welcome; I'll go ahead and delete your same question in the other thread.

EPS board is used throughout the construction industry these days UNDER concrete slabs, to meet the insulation requirements; I've yet to hear of any serious amounts of compression as long as proper compaction was used for any soil or gravel UNDER the slab before the pour.

If you were to take a 12' x 12' free-standing building on top of a 5" thick concrete slab, you'd have a total weight of around 12,000 pounds more or less - dividing this by 144 square feet you get about 83 pounds per square foot - divide that by 144 to get PSI, and you come out with just under 0.6 PSI - this amount shouldn't cause anything further than a slight settling, as long as you don't get infested with Plastic-Eating Termites from Mars, or spill a few gallons of MEK or Acetone in the vicinity... Steve

[sebring]

That's good news
Thank you!

I will have to move soon and consequentially need to build a new studio, so I'm interested to know whether a full floor of neoprene and then flooring on top of that is better for isolation than creating a floor resting on posts that are on the neprene pucks.

Also, it would seem that if I have a a control room and two other rooms, say, it would be better to make the control room a completely separate room - that is to say there would be an air space between the control room walls and the walls of the other rooms and a seperate floor as well.

Thanks,
mike

[sharward]

It would be hard to get a soft enough Neoprene that would compress enough under such a large surface area to create a spring effect. That's why pucks are used.

Consider an isolated slab rather than a floating slab. I'm not against floating, but it's soooooooo hard to get it right and soooooo easy to get it wrong... Even when you think it's right!

--Keith