I would use the Tapcon screws. I think it's the most reasonably priced
method and it works really well. Rent a good rotary hammer drill if you
don't have one, buy the specified diameter bit for the size Tapcon screw
that you will be using (maybe a spare or two) and it will be an easy
installation. A good standard driver/drill will easily drive the screws in
once the holes have been drilled. Make sure that you drill the holes deeper
than the screws are long to allow for a debris pocket under the screw.

--
Charley


wrote in message
oups.com...
On May 11, 9:24 am, Marianne Halevi 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.

Marianne

--
Marianne Halevi

If you have a ROTARY HAMMER drill, not a hammer drill, then Tapcon
screws will work very well. Not the plastic anchor things you
mention. Tapcon screws bite into the concrete itself and hold well
enough for anything that is not subject to extreme forces. You don't
have to use lots and lots of Tapcon screws to hold the plywood down
since gravity will help considerably. Use the correct undersized
drill bit. Something like 5/32" drill for 3/16" screws I think.
Hammer drills are so slow and stop when hitting aggregate I cannot
stand to use them with Tapcon screws. I hate hammer drills. For
attaching electrical boxes to concrete walls, use the Tapcons with a
rotary hammer drill.

The powder actuated nails work very well and are very quick. Every
now and then you get blowout of the concrete. But not too often
really. You minimize this occassional problem considerably by firmly
pressing down on the wood being fastened to the concrete. For
attaching framing to floors and walls in basements, this is the method
to use. And any blowout is going to be underneath and hidden so you
will never see it or even know.