Stage, not Platform, Construction

[goshen28]

We have to replace a stage in our room. Currently we are using 4x8 temp staging bolted together into a stage 24 wide and between 8 and 16 feet deep. The stage has become squeaky and noisy, plus with acoustic drums and electric bass on it, it is really a boomy drumhead.

We are going to replace this stage with a new one. Here are the details. The room is 50'x50' with 16' high ceilings. The new stage will be 24' wide X 18' deep (rectangle), and a height of 16 inches. It will be permanently installed. The top will be either painted black or dark carpet. I will have one stage box at middle downstage with two power outlets, 2 XLR returns for monitors, and 3-4 XLR sends for mics. All other connectivity will be on the wall backstage. Stage is used for speaking and music - live acoustic drums, electric guitars and bass, keyboards, etc.

I have spent a couple of hours searching and browsing the forums looking for details on stage construction technique and most of what I found was geared towards platforms and temporary staging. While the flooring info was thorough, I'm still stuck trying to understand the best way of framing the stage. I also am looking for suggestions on how best to remove resonance to decrease mic rumble.

 

[DuckJordan]

For a permanent stage call a contractor...

Sent from my XT1060 using Tapatalk

 

[BillConnerFASTC]

Frame it like a house. I'd probably build three very short "walls" across the 24' width and fill in at sides will wall - single 2x4 top and bottom plates, and studs. I'd like to check a span table but I think 2x8s up and down stage. They should align on top of studs. One left to right upstage and down stage. Lay fibreglass on floor to dampen echo. (I might blow it full of cellulose - would realky deaden it.) Sub-floor and flooring. The more density in the flooring, the better. Close off sides so no one can store under it else it needs to be sprinklers or divided up in less than 100 sq ft compartments for code compliance. Cement coated nails. Screw and glue sub floor to joists. Precise square cuts. All those things should help prevent squeaks.

PS: for a fee, I'll prepare drawings.

 

[BillConnerFASTC]

PSS: I might put a layer of 15 pound roofing felt between sub-floor and floor since its sometimes reported to reduce or prevent squeaks.

 

[robartsd]

divided up in less than 100 sq ft compartments for code compliance

That would explain why I've seen solid filled walls between bays of under stage storage at some facilities (the stage I work on most frequently is probably grandfathered in before such requirement). With stage depth of about 24' and bay width of less than 4' it stays under the 100 sq ft limit. Also with walls that frequent, there really isn't all that much of a span for the deck. Of course the storage under a 16" high platform is totally not worth that kind of effort.

 

[goshen28]

Thanks for the great advice, Bill. It was just what I needed.

 

[BillConnerFASTC]

If you want to discuss details, pleased ask. You're welcomed.

 

[lwinters630]

We have to replace a stage in our room. Currently we are using 4x8 temp staging bolted together into a stage 24 wide and between 8 and 16 feet deep. The stage has become squeaky and noisy, plus with acoustic drums and electric bass on it, it is really a boomy drumhead.

We are going to replace this stage with a new one. Here are the details. The room is 50'x50' with 16' high ceilings. The new stage will be 24' wide X 18' deep (rectangle), and a height of 16 inches. It will be permanently installed. The top will be either painted black or dark carpet. I will have one stage box at middle downstage with two power outlets, 2 XLR returns for monitors, and 3-4 XLR sends for mics. All other connectivity will be on the wall backstage. Stage is used for speaking and music - live acoustic drums, electric guitars and bass, keyboards, etc.

I have spent a couple of hours searching and browsing the forums looking for details on stage construction technique and most of what I found was geared towards platforms and temporary staging. While the flooring info was thorough, I'm still stuck trying to understand the best way of framing the stage. I also am looking for suggestions on how best to remove resonance to decrease mic rumble.

Check out this sound proffing. http://www.greengluecompany.com

Also there are a lot of posts stage floors. Be sure to paint all 6 sides, space, and secure per mfg recommendation. Carpet is my last choice for floor, but if you do, go with dark grey. Black will show too much.

 

[BillConnerFASTC]

With respect, I think spending $0.50 per square foot on thicker sub-floor and finish floor before a premium glue would provide more return.

I too would prefer other than carpet, and strongly recommend plyron (which doesn't require paint on edges and bottom) but know worship platforms all seem to prefer and be happy with carpet. Look at anti-static ratings and treatment.

 

[goshen28]

In an effort of hitting my 16" height target, and also to facilitate compartmentalizing sections <100 sq ft, I'm thinking I can build my "walls" the joists will sit on with a 2x4 bottom plate, a 2x4 on its side for wall height and then the 2x4 top plate (see pic). Still debating whether the top floor layer should be plywood or plyron. BTW, where do I buy plyron in Seattle - are there easier to find alternatives?

 

[BillConnerFASTC]

I'm not worried but the 2x4 "I" isn't really one hour rated. You'd need to build a little wall and cover both sides with type X drywall. I'm guessing a building official would accept just enclosing at sides to prevent storage. You can ask.

Plyron is usually special order. You'll need to call the company and ask. (I did not intend plyron unless you are just painting.)

I was probably not clear but felt between osb and ply in your detail.

Others would suggest hardboard on what you drew but a lot more fasteners and if in a humid climate you can get swelling.

 

[JohnD]

It shouldn't be too hard to find plyron in Seattle since it's made in Shelton, Wa.
http://www.olypanel.com/index.php
I was just reading this from APA and was wondering if using I-Joists would make sense?
http://www.apawood.org/premium-floor-assembly

 

[BillConnerFASTC]

I-joists are designed to span and don't deal with compression very well, so not to sit on floor. Might make some sense for a much higher stage, but their advantage is in longer spans than regular dimensional lumber can do well. You don't want long spans in this case because then the load at the bearing points grows till you need to cut floor and pour a footing. I wondered if I should have suggested another knee wall and 2x6 joists - because it spreads the load.

 

[kicknargel]

My understanding is that you'd need to pull a permit for this and have inspections. Right?

 

[venuetech]

most plywoods have voids within the ply. these voids allow the surface to be crushed by heavy point loads, such as piano casters. that may not be an issue for your purpose. the floors i have dealt with have had a red rosin paper, or a heavy kraft paper rather than roofing felt.

As far a mic rumble is concerned i would avoid cast iron base mic stands or put isolation / shock mounts on the problem microphones.

 

[BillConnerFASTC]

My understanding is that you'd need to pull a permit for this and have inspections. Right?

Well, I'm not sure. It could be scenery, which is exempt from requiring a permit. On the other hand it could not be scenery, and then probably require a permit.

I may have been miss-remembering or remembering from an older edition of the code (IBC 2015 - but unchanged for many years). Here is what it says:

410.4 Platform construction. Permanent platforms shall be
constructed of materials as required for the type of construction
of the building in which the permanent platform is
located. Permanent platforms are permitted to be constructed
of fire-retardant-treated wood for Types I, II and IV construction
where the platforms are not more than 30 inches
(762 mm) above the main floor, and not more than one-third
of the room floor area and not more than 3,000 square feet
(279 m2) in area. Where the space beneath the permanent
platform is used for storage or any purpose other than equipment,
wiring or plumbing, the floor assembly shall be not less
than 1-hour fire-resistance-rated construction. Where the
space beneath the permanent platform is used only for equipment,
wiring or plumbing, the underside of the permanent
platform need not be protected.

So if you treat it as permanent, and get a permit, you'll have to determine construction type, or actually what construction type is required by use and occupancy classification and by the height and area of the building. Depending on the jurisdiction, more rural areas being a little friendlier typically, you might just go in and ask. I feel with nothing under - and in 16" that would tough anyways - you ought to be allowed to build with any lumber and with a heavy deck (1 1/2" or more all told) and drywall around sides - but YMMV. Any local building contractors in your organization you can get friendly and informal advice from?

 

[BillConnerFASTC]

most plywoods have voids within the ply. these voids allow the surface to be crushed by heavy point loads, such as piano casters. that may not be an issue for your purpose. the floors i have dealt with have had a red rosin paper, or a heavy kraft paper rather than roofing felt.

As far a mic rumble is concerned i would avoid cast iron base mic stands or put isolation / shock mounts on the problem microphones.

Originally the red rosin paper - based on what I researched once - between wood plank sub-floor and finished strip wood floor - was to prevent plaster from sifting through to floors below. I mention teh roofing felt (asphalt paper?) because it seems to allow slipping or rubbing without squeaking, or so it seems.

Actually, in working on my 110 year old house, I am amazed by the condition of the original rosin paper - both in the floors, under siding, and under the wood roof shingles. It is like new. Fun to find the labels from 1904. Pretty durable stuff. So maybe red rosin paper is fine, but I suggest one or the other as a squeak preventative. A layer of Homasote 440 (I hope that name has not become politically incorrect) would also be a nice interlayer, or base for carpet. Once in every building supply, it's hard to find today.

 

[goshen28]

Thanks for all the feedback. After poking around, and leveraging some of the ideas in the thread, I've planning on the flooring to consist of 1/2" soundboard, 1/2" OSB and 3/4" plyron which will be finished by painting it black. This is to minimize noise and resonance and still provide a clean stage surface. Does this make sense?

I'm also leaning towards 14" lam beams on a 2x4 bottom plate (see attached images Lam Beam cross section and Lam Beam Framing). Alternatively, I'd go with 2x6 joists and knee walls as needed to provide structural support (see attached images 2x6 cross section and 2x6 Framing). FYI, the stage will be completely enclosed (no storage). Any approach look better than another?

 

[BillConnerFASTC]

I find 3/4" ply to be not strong enough in bending between two-bys 16" OC, and the 1/2" OSB will contribute next to nothing. I'd either change to 12" centers or up the 0SB to at least 3/4", which will double its strength in resisting bending. Or use even thicker OSB.

I specify 1 1/8" ply on sleepers which is a 12 1/2" span versus your 14 1/2". If using 3/4" ply, I move sleepers to 12" OC which is a 9 1/2" span, for near equivalent of 1 1/8" 16" OC.

I don't know what your building on, but can't believe the existing floor - I'm presuming a slsb - is near flat and level enough for any straight member to sit firmly without any rocking let alone a whole series being co-planar. The fewer the points of support the easier to shim and the greater likelihood of no wobble.