Looking to have 3 1/4 x 5/8 bamboo installed in the finished basement of a home I am building for a client.

The desired direction would run with the sleepers as opposed to perpendicular.

The sub floor is 6 mil over the concrete slab with pt sleepers and "infill" between sleepers is 1 1/2" solid foam board insulation. - ("...rigid, foam plastic, thermal insulation board composed of environmentally sound, closed cell, polyisocyanurate foam bonded to a glass fiber reinforced heavy 1.5 mil aluminum foil facer on the exposed side of the board.") bringing it level with the sleepers and with 3/4 T&G glued sub-flooring on top.

The client is concerned with not running as "standard" perpendicular to the "joists"= sleepers.

I feel that there is not a concern for deflection between sleepers given the situation.

Wondering what the experts think??

Thanks--- Roy

Have never referred to myself as an expert, except in covering my azz. If the client wants the floor to go perp to the sleepers, what is your objection? If anything (did I say ANYTHING?)
should go wrong with the install; not laying it this way will come back to bite you.

Sorry- should have made myself clearer.

The desired direction is as mentioned, but client worries "would it be a problem?"

Intuitively, I can see no problem with any bounce or deflection given the sub-floor construction.

What is the spacing between sleepers?

16" o.c.

Well, you could most likely install parallel without issue. One thing to be certain of though, is that the fasteners do not penetrate the 3/4 ply. You would definitely have annoying squeaks wherever they touch that insulating board.

Thanks- I don't believe there will be any give between the sleepers.
Am wondering about nails in the inso board.