[Usittne] Flooring question

[Clyde Tyndale]

Hello All,

I'm looking for any advice any of you has to offer.

At Falmouth Academy, we recently had a small disaster - a sprinkler pipe burst early one morning 
about 10 days ago and flooded the floor in our performance space.  The floor was damaged to the 
point where is must be replaced.

The space is a converted multipurpose space which was once used as a gym and still has the maple 
hardwood floor.  It is no longer used as a gym, and is now essentially a black box theatre space, 
although still used for some other similar purposes (classes, large meetings, etc).

The current floor is 2.5" maple T&G boards installed using a clip system to steel rails 12" o.c. 
The steel rails are on concrete.  Total thickness above the concrete is approx 1.5" and we need to 
maintain a thickness very close to this for ADA compliance at doors, etc.

We see this as an opportunity to get a floor that is more appropriate for a black box theatre.  We 
use it as a flexible space, so any part of the floor at one time or another may be used as stage 
area or audience seating area on a flexible and movable riser system.

The space does not have good climate control at this time and may not have air conditioning 
installed for several years.  Being on Cape Cod, the humidity variations from winter to summer can 
get pretty extreme.  The old floor has proved pretty resistant to buckling and other humidity 
related problems.

Having a good dance floor is not an important consideration as we don't have a dance program.

We have heavy rolling loads - including grand pianos, a small pipe organ, and carts which hold our 
riser system parts.  The loaded carts can weigh up to 1200 lbs each.

The riser places significant point loads - the foot pads are approx 2.5" dia., spaced on 3' x 8' 
o.c. grid.  The unloaded system weighs 6,000 - 10,000 lbs, plus up to 240 people sitting on it.

Of course, we'd like a floor we can drive screws into, fasten anchor points to, repaint as 
necessary, and that will be reasonably quiet when people with hard soled shoes walk on it.

We are considering as possible flooring (all to be painted flat black):

Fir T&G boards, on the existing steel rail system.  These would be approx 3/4" trhick

Fir T&G boards over plywood, directly on the concrete.

High quality plywood, double layer, directly on the concrete.  Must be void free, at least the top 
layer.

Masonite or other laminate over plywood, directly on the concrete.  My experience in another venue 
is that untempered masonite will expand & contract significantly with humidity changes.

Black sheet vinyl over plywood, directly on the concrete. (might not withstand the rolling/point loads)

One bidding contractor has proposed 1/4" Stagelam over a double layer of plywood, directly on the 
concrete. This looks very promising.  Do any of you have experience with this product?

Fortunately, all of these appear to cost less than the cost of installing a replacement maple floor 
which will be covered by insurance.

Do any of you have any suggestions or advice to offer?

Thanks

Clyde Tyndale
Falmouth Academy