I am in Indonesia, and have constructed a small mezzanine approximately 2.7m x 4.4m, 2.5m off the ground (roof is steeply vaulted, so there is still headroom). Construction is hardwood (bengkirai) joists and I have bought 18mm plywood which would just go on top.
Anyway, this construction is fairly standard in Indonesia but then construction standards in Indonesia are not standardised, so let's not say they are correct, just that's how things are done.
I think in that one they are using nails, but drywall screws are widely available, but I think maybe worse than nails?
There is no 'subfloor' screw, but I found these online (also in 1/4" x 1 1/2"), which they are calling a deck screw:
I don't think adhesive is used here, but I called Sika Indonesia and they were slightly confused by my question, but said they have adhesive for parquet flooring, which is called SikaBond T-53, a "1-component, wood flooring adhesive with high viscosity", which is polyurethane, but suggested maybe MaxTack Ultra, which is 'silane terminated polymer' would be appropriate.
The usual thing here is to put cheap thin plywood and replace it when it fails, since the labour costs are very low, so it makes sense economically to do that, rather than a multilayered floor system designed to last for many years. Since my builders don't know about floor systems anyway, I want to use my slightly thicker plywood as a floor, so I'm not sure if should either:
- glue and nail the boards, or
- screw the boards with no glue (which fasteners?)