RFC: new construction 25x25x10 rehearsal room in No. Calif

[Antny M Studioless]

Tidings All,

I'm happy to finally post this request as I've approval for a concrete slab floor 'auxiliary structure'. It will be 25'x25'x10' (exterior dimension) with 2"x6" stud walls and plywood exterior. The interior is the challenge.

A goal is to get the room as quiet as possible at 10', which is where our neighbors keep a horse. There is a 8' high fence that separates the space from the horse.

I'm stumped as to what materials and design to use for this project.
The drawings below are my starting point:

http://www.johnlsayers.com/phpBB2/files ... n3_171.jpg

http://www.johnlsayers.com/phpBB2/files/spc-fl1_815.jpg

The ceiling will be a standard 12:5 truss design. With 10' walls, my hope is to get enough sound isolation to get at least a 8' ceiling.

As much as I'd love for this to be a proper studio, the space will also be used for storage. There is a need for up to 12 3'x6'x6'high industrial steel shelf units which will house heavy stuff (LP's, books, fishing lead collection). As this will hopefully change over time, a thought is to place the shelves around the perimeter of the room and then build movable panels to both decorate and tune the room to taste.
Another note: the room will have 2 4'x8' double pane windows on adjacent walls and a 4'x8' double pane glass door on a third wall. (The wall closest to the horse gets no windows :})

What materials/caulk/insulation can be suggested, for this sort of project with a location of Northern California, okay the 'Wine Country'...

Many thanks for the read, interest and comments. Thank you John for a supremely fascinating site!
Antny M Studioless

[knightfly]

Hey Antny, welcome - first, I'd forgotten about those drawings - I've since learned that it's a VERY bad idea to leave ANY air space in a floated floor or you'll get boominess. It's better to fill completely with rockwool - if it's ALMOST full, you can then add 1/2 width strips of unfaced, standard fiberglass insulation centered between joists and running parallel to them, to dampen the floor. You want enough compression to maintain medium-firm contact with the underside of the first layer of flooring installed.

Second, using staggered studs was not intended as BEST isolation, just appropriate for the person I drew that for - better is to use completely separate frames with only one side of each frame paneled; see the far right example, titled 63 dB, bottom of the page here

http://www.domesticsoundproofing.co.uk/tloss.htm

The floor in the drawing you posted, other than the changes I mentioned just now, will work fine for a free-standing, raised block type of construction; but for a SLAB, you would need to do it differently.

Before I get into that part much further, I need to know what instruments you intend to play (and how LOUD) in the space, and whether you want the sound to be completely IN-AUDIBLE at 10 feet, or just "not too loud" - any info on local noise statutes would also help if you can find them... Steve

[Antny M Studioless]

Greetings!

Thanks for the reply. You're right: after rereading a number of posts, a design similar to the -63db flavor found at

http://www.domesticsoundproofing.co.uk/tloss.htm

makes more sense. As is, that design shows both outside walls using two layers of sheetrock. What would be appropriate for an exterior wall equivalent: two layers of plywood? Also - would a 6" (150mm) gap between walls be optimal? What would be a suggested thickness for the sheetrock? Some posts suggest using the same thickness for both layers, others stagger the size.

As for the floor - where might one find rockwool in No. Cal? It makes sense to fill the floor as mentioned. The rest of the floor design, that is from top to bottom:

3/4" ply
2x 90# roll roofing
3/4" ply
2x6 joist (gaps filled with r-wool)
1" neoprene pucks or auralex U-boats: how are they secured to the joist or floor?

I'm in a rural area, and the county does not appear to have any specific restrictions on noise with regard to construction in the area. The group that will be rehearsing is closest in db to a Spinal Tap tribute band = Marshalls + 9pc drums + PA. Inaudible at 10' is ideal, but not enough to stir the horse would be realistic.

Given the above, what would be a comprable ceiling design?

Many thanks - this is getting exciting fast,
Antny

[Antny M Studioless]

Tidings,

I wanted to <bump> and see if the wall and floor designs from
the Gleeman project might fit the bill

http://www.johnlsayers.com/phpBB2/files ... _wall1.gif
(except concrete outer wall would be replaced by 2x5/8" ply)

http://www.johnlsayers.com/phpBB2/files/inner_wall1.gif
(and both inner and outer walls use 2x6")

Many thanks again,
Antny

[knightfly]

Given the type levels you mentioned and the desire to keep the noise under control, you would be better advised to look at the construction details posted by Sharward for his drum practice/rehearsal area -

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=2921

If you use two layers of 3/4 OSB for outer leaf on walls, then at least an 8" total air gap, then 3 layers of 5/8 gypsum wallboard for the inner leaf, this would result in roughly 41 dB TL @ 50 hZ, with an STC of around 74 -

an equivalent ceiling, using trusses, would be to hang 3 layers of wallboard on the trusses themselves, then support a floated ceiling on your floated floor with 3 more layers of 5/8 wallboard - spanning the entire width of your space without any inner partitions with enough support for this much weight would require 2x12 doug fir ceiling joists on 16" centers. The trusses would need to be spec'd for 20 pound dead load on the horizontal chords, standard is usually 10 pounds (sometimes only 5) but these won't support enough weight for this.

In order for your floor to keep up, you'd need some kind of heavy mass on good elastomer pucks - something like PT 2x6 on edge over 1" EPDM or Sylomer pucks, topped with 3/4 OSB, 6 mil poly, and 3-1/2" poured concrete inner slab would give you as good isolation as the walls and ceiling I described.

Assuming a 10 foot wall height, leaving space for the 2x12 inner joists and wallboard (about 14") and space for the floor I described (11") you would still have about an inch shy of 8 foot headroom.

Now, for the bad news - that large a windows will cost you a FORTUNE assuming there's any left after all those 2x12's and the other materials - in order for a 4' x 8' window to keep up with those walls/ceiling/floors, one glass would need to be 5/8" thick and the other 3/4" thick, assuming the two glasses were 12" apart.

If the windows were 3' x 4', you could get the same result using 1/2 and 5/8" glass, even with only 8" separating the two panes.

Since low frequencies are almost totally omnidirectional, any "thump" that escapes your windows will just kind of "wrap around" the building and go all directions.

If you can get an idea of what all the materials I mentioned will cost and still want to do this, I can help with the design further - BTW, you will also need an airlock-type double door to match your walls and other parts of the construction - two exterior grade, heavy pre-hung doors at least 3 feet apart with good seals will work pretty well for this... Steve