SUGGESTIONS NEEDED - 1890's victorian home in HUMID Houston Texas with extreme heat. raised pier and beam foundation approx 18" over dirt ground w/ventilation (lattice perimeter). existing floor is 5/8-3/4" x 3" fastened directly to the joists (no subfloor or insulation). professionally refinished several years ago without much success due to uneven gaps, holes and patches....too much character for my taste + energy bills are outrageous. the product I am considering is Lumber Liquidators product #10023902 Morning Star Clic Bamboo - 1/2" x 5" Tongling Stained Solid Strand Bamboo Flooring.

MY CURRENT PLAN is to cover and seal the ground with 6-8 mil plastic sheeting, lay 15lb roofing felt over my pine floor, screw down 1/2" cdx plywood, use floor leveler and sand joints if needed, unsure which underlayment to use, then float the floor leaving 3/8"+ gaps along perimeter. Raising the floor height will not be an issue. I’m removing all molding, cabinets/appliances and trimming doors. I want the job done right, without spending extra $ on unnecessary products. Removing the 120+ yr old original 3/4 pine is not an option!!!

my questions/concerns are:

float, staple or nail? it is a Click flooring and the manufacturer specs say DO NOT nail or staple, but the sales people at LL said fasten it down!?!?!? If fastening, what type/length of fastener should be used? I would prefer that the fastener not penetrate the original pine floor

subfloor: is 15lb roofing felt as a moisture barrier okay, or use another product? Will this moisture barrier (placed over original floor) rot away the pine flooring over time?

underlayment: if floating the floor, what is a good underlayment? nothing “fancy” needed, it is an OLD house so noise and cushion are not a big concern. An Insulated product would be a bonus!

ANY and all suggestions are appreciated. Remember, I am located in a very HOT and HUMID climate. Thanks!

if it's a click lock floor i would float it. I wouldnt put felt between the two layers of subfloor id save it for the top of the subfloor but with your floater your going to need a moisture barrier/ foam underlayment anyway. Id do any leveling under the plywood if at all possible.