Is it time to panic?

[Todzilla]

My builder is working on my detached studio (as per an earlier post). We agreed on a 16' X 23' space with a cathedral ceiling going from 10' up to 15'. What I failed to account for is those were outside [\B]dimensions.

So, instead of the groovy odd ratio of 1 to 1.43, you take away the cinder block width and the stucco and you are almost at 1 to 1.5 which looks dangerously close to producing the same resonant frequency (or whatever you call them) at 2 times the depth and 3 times the width.

Of course, I can't do anything about it now (foundations are poured, floor is laid down) and it is really my miscalculation, not my builders. Am I mountainizing a molehill?

Another thing, the walls are stucco'ed cinder block, but the floor is plywood on joists. Am I gonna have a wicked floor resonance problem?

Please respond with the knowledge that I am highly budget driven.

Cheers,

 

[kristian]

I don't know about your problem, but i was in North Carolina this weekend, and damN! that place is nice. I was at Wake Forest University in Winston Salem looking around and seeing a friend. We went to hanging rock state park, it was awesome.

 

[Todzilla]

Shhhhh!

It's crowded enough down here.

 

[John Sayers]

Todzilla I'd be concerned about the floor resonance. I'd glue insulation to the underside of the plywood and probably lay a double sheet of ply if your budget can afford it. Doubling the ply will lower the resonance frequency.

good looking kids mate

cheers
John

 

[Todzilla]

Thanks John!

I'm deep in change order mode with my builder (who is also building the house in the background), so extra layers of plywood may require me to ask my wife to forgo the gold plated wallpaper in her 20' X 30' closet, if you catch my predicament.

With just a single layer of plywood, I would expect to have excessive boominess from low frequency sources, no?

Lastly, did you have any concerns about dimensions that are almost exactly 1:1.5 in width:length ratio?

Cheers,

 

[ausrock]

Todzilla,

What is.......... the ply flooring thickness, the joist spacing and have you good access to the underfloor area?

Peace........ChrisO

 

[John Sayers]

The ratio problem depends on how you treat the interior really.
You can break it up with internal treatment.

Heavy carpet underlay will help the floor resonance.

cheers
John

 

[Todzilla]

Aus and John,

The joists are standard spacing for US residential construction (I think they're every 16 or 20 inches. I should also mention there is a huge cross joist thingy that bisects the floor into two 7' X 21' sections, such that the flooring joists rest on top of it perpendicular (damn, was that a confusing explanation). This huge cross support rests on at least one pillar that goes deep into a concrete footing. My builder pointed this out to allay my concerns about a giant resonant membrane. His point is that with the joist system. It will really be two half sized resonant membranes and he thinks it will be minimal. Luckily, he is a pretty serious bass player too, so I think he is pretty in tune with my concerns.

As for flooring thickness, it is standard 3/4" plywood, but he seemed totally fine with another layer of plywood. He even thought it would be nice aesthetically to have a fine veneer finish on the second layer, so the floor would look nice.

He made sure there is adequate crawl space underneath which varies from 4' to 2' in height. So, yes, I can get underneath and commune with the spiders as I address any issues therein.

I am reluctant to use carpet, because I don't want a dead room. I'd rather start with a boomy live room and then apply the minimum treatments to tame it. Perhaps carpet will be a part of that solution, who knows?

Thanks,

 

[John Sayers]

That sounds fine mate - glad you've got a good builder.

cheers
john

 

[ausrock]

Todzilla,

My thoughts were to put noggins in between the joists at set intervals. If these were a neat fit, pressed hard up to the underside of the flooring with liquid nails, nailed to the joists at each end and then from the top side, SCREW the flooring to them while the liquid nails is still softish you should deaden the floor somewhat more than it already is. Even if you only put them under the points where sheets of ply join.

I did this for different reasons here a few months ago and the difference was surprising.

John may care to pass comment further.

Regards.......ChrisO

 

[CDT-sHaG]

off subject...but i live and work very near wake forest...nice to see a few posters from the area...

 

[frederic]

I coincidentally have a lot of experience with floors and soundproofing, and you can do a lot with common materials. Layering one floor front to back, then attaching another floor (plywood) on top left to right goes a long way. Glue, tongue and groove (good excuse to buy a router if you are into tools!) go a long way. Seal it well, make it heavy, well supported, and lows won't resonate the floor. If you are concerned about transmission through the floor into the joists, mount the wooden floor to the joists using rubber blocks, or something hard yet soft. This isolates the floor from the rest of the structure, and then using ordinary moulding around the perimeter of the room, you now have a floating floor.

Thanks John!

I'm deep in change order mode with my builder (who is also building the house in the background), so extra layers of plywood may require me to ask my wife to forgo the gold plated wallpaper in her 20' X 30' closet, if you catch my predicament.

With just a single layer of plywood, I would expect to have excessive boominess from low frequency sources, no?

Lastly, did you have any concerns about dimensions that are almost exactly 1:1.5 in width:length ratio?

Cheers,

 

[John Sayers]

noggins in between the joists at set intervals

Good idea Ausrock. For those who don't understand the term NOGGIN it's a joist going at 90 degrees between the joists for extra strength.

cheers
john