Hello good peoples of the Hardwood,

First of all, I thank and admire those who have contributed to this website for the professionalism and time spent making a knowledge base for pros and DIY's. One of the FEW good resources online.

In short, what would YOU do in my situation?

MATERIALS & TOOLS READY TO GO

1. Bamboo 5/8" Thickness, 3 & 4/5'' Depth, 37 4/5'' Length. Horizontal 3 ply. Prefinished.
2. Porter-Cable FCN200 cleat nailer for 1.5" cleats.
From reading other posts on this forum I assume I have to shim the shoe on it because it is set up for 3/4". Correct?
3. Big air compressor, and stapler for underlayment.


THE ENVIRONMENT:

We are in San Diego, CA, where it is currently (strangely) very humid like some places in Arizona and New Mexico. I would assume we should wait on the installation until this humidity passes? The bamboo has been acclimating for 4 days now, before this humidity came. Thoughts on that?

We've installed over 400sqft of Brazillian Cherry on our own in the livingroom and a bedroom. Now for the upstairs room at about 350sq.ft, we've chosen Bamboo. It will be used on one half of the room for living quarters; 2 dressers and a corner built-in L-shape military bunk will hold 4 hard working brothers. The other half will have a full seamless, wall-to-wall built in heavy duty workbench for production of sculpture, jewelry, painting and other art. Heavy hardware will be mounted to the workbench for fabricating metal. No worries, the flooring near the workbench will have 1/2" rubber horse stall matting to protect the surface.

Underlayment is where I'm concerned. On the one hand we want the floor to be fairly quiet, while still sturdy and solid enough to handle weight on the wood (from bed, dressers, and workbench).

The subfloor is above a garage, 30 yr old construction but with beefy 3/4" or 1" plywood (forgot which thickness, we'll find out after the carpet is ripped up again), with 16oc joists.

1. Would 30lb tar paper deaden sound while being sturdy enough for a workplace?
2. Or would a product like Armstrong quietcomfort underlayment be overdoing it?
3. We used 15lb tar paper with the Brazil Cherry, would that work just as well for our upstairs purposes?
4. Do we have to hit all the joists, or will it matter if we hit anywhere on the ply as well?

We really have no need for a moisture barrier, just sturdiness and as quiet as possible (the happy medium).

I appreciate all the help possible. I will be shopping for underlayment as soon as some answers are settled here.

Many thanks,