Marianne Halevi wrote:
So I'm back with a question about my T&G wood floor in the converted
garage. I was going to put 3/4 inch plywood down on the cement floor
first, on top of a vapor barrier. How do I make sure the plywood stays
down? One person says shoot 22-caliber nails, 6 or 8 per 4x8 sheet of
plywood (he would lend me the gun), another says drill through the
plywood into the cement and put in screws with those plastic anchors,
because shooting in the nails might explode the cement. I'd be totally
grateful to anyone sharing their experience with this.

I'll play the devil's advocate for a moment.

Yes, you could shoot Hilti nails, yes you could drill for concrete
anchors, but WHY?

Assuming this is a typical garage of about 10 x 20, accurately fitting
and installing plywood cut from 4 x 8 sheets is NBD.

(BTW, a typical sht of 3/4 ply weighs in around 60-65 lbs)

A layer of 3/4 T&G on top of the plywood will insure minimum movement
of the plywood sheets relative to one another.

It will also add another 50-60 lbs/4x8 section.

On top of this construction, equipment, benches, etc, will be placed.

Assuming the floor is kept dry, nothing is going to move or warp.

BTW, I'd use adhesive rather than nails to install the T&G.

Lew