Bamboo and Exotic Wood Floors - sub-floor question

I am installing 3/4" thick x 4" wide random length solid bamboo strip flooring. The bamboo plank has T&G edges and ends and is the nail on type.

The subfloor is 1 1/8 inch thick T&G plywood over 4x6 joists 48inch on center. On top of this is 1/8" thick x 8" x 8" vinyl tile that is glued on with mastic ( the old abestos type tile, home was built in late 60's ). The tile is missing in places but otherwise stuck on pretty well.

My question is do I need to remove the tile or will patching it be sufficient? Or can I cover it with plywood without patching? If I remove the tile is 30 lb felt enough of an underlayerment?

Any other options or ideas will be appreciated. Thanks in advance.

With 48" spacing of the flooring joists, I would relaminate the surface with at least 1/2" plywood prior to installing the bamboo. The possibility of flexing between the joists is a paramount problem that you must address. How old is the house and what kind of construction is it that calls for such a wide spacing between joists? Just curious.

and they used 2 x 6 for floor joists?

thanks for your response.

the house is a single wall redwood home built in the early seventies. this style of post and beam construction was very popular here in Hawaii up through the early/mid eighties. no, there are no 2x6 on top the 4x6 joists.

when I lay the 1/2" sheathing should I use panel adhesive and do I need to patch existing subfloor?

I have already removed the linoleum tiles. is the black mastic okay to leave there or does it need to be sanded?

thanks again

lokahi

summer swell from the south, onshore winds, 8-10 feet

OK, let's start over. You have 48" between the beams of the floor. No joisting per se. What size boards (thickness and width) comprise the subflooring? How thick is your total subflooring? I think our main concern is the flexing of the subflooring between the 48" if it isn't substantial enough.

it seems that 1 1/8" thick existing ply floor should be fine, if you can run the bamboo planks perpendicular to the 4 x 6 this will give you some added stiffness....

if the mastc is not to uneven it could stay...30# felt will help even it out.