concrete slab vs/ wood floor - pros and cons


Audiogoners, given the choice, with sound quality being a top priority, which choice is usually better?

I have been given the green light from my wife, bless her heart, to convert our stand-alone 1935-era garage into a dedicated music/theater room - woo hoo!! The fact that it's a separate structure will be ideal for playing loud movies whenever without bothering anyone in the house. The space is roughly 11.5 x 17' and I think it will make a terrific intimate theater. It's completely unfinished inside and has a sturdy stucco exterior. It's a very solid structure. However, the concrete floor has some large cracks lengthwise due to settling so it is pretty crowned in the middle. If I keep the concrete, I will need to build a floor over the slab and shim it quite a bit to level it out enough to install the underlayment. Headroom is limited as the walls are just over 7 feet, although the roofline peaks at just over 10' in the center, enough height to hang my projector.

If I removed the concrete, then I could dig down and build a normal floor over wood joists with a nice hollow space underneath. My house is built over a crawlspace with hardwood floors and I like the quality of bass and overall sound I get in our living room. The downside is that it would be more difficult to convert the garage back later to use for parking a car if we move. I was thinking it might be cool to design this type of floor and then have space below for insulation, wiring, etc. without sacrificing any height. Maybe the floor could even be designed as a sort of bass trap to help with the sound. Any thoughts? -thanks, -jz


john_z
Removing the concrete floor may cause you problems. Sounds like what you descibe is a floating slab construction where the entire weight of the garage is spead out over the 11 by 17 area. If you remove the slab what remains is the concrete under the wall. This may not be strong enough to support the walls or may shift under the weight of the structure or underground water which could cause everything to come down. Also, you don't know if the concrete has wire mesh or rebar which would make removal difficult. If you're really gung-ho about it, check with a civil engineer. I would also talk to contractors who do foundations - that floor may very well be capable of leveling without too much loss of headroom.
Yeah, stick with the slab and cover a large portion of it with thick carpet or rugs. It make a great base for speakers and turntables.

Dave
How about just pouring a little more concrete over the top...sufficient to add about 1" to the high spots and level the low spots?

Then you don't need to go adding a shimmed subfloor, maybe just plywood over the top, if desired.
Gs5556 has given you some good advice. I'd stay with the concrete floor; there are many products on the market for leveling your existing floor (Ardex feather-finish is one I've used alot, and is a great product). If you are'nt able to do this, then find a contractor who can. Then I would just go ahead and carpet/pad over the concrete. My sound room in my basement has this arrangement, and the sound is great.
The thought about later selling your home and needing to convert this room back to a garage should be a strong consideration to stay with the concrete.