On Oct 15, 1:47*pm, Joe wrote:
Thanks for the definitions. *He used the wrong word, so stop being a
smartass and learn something.

I wasnt being a smartass. It seemed he was suggesting that I install a
3rd layer. I already have a subfloor. He agreed with the other poster
that I should install my 5/8 across the joists, and then suggested I
install a 1/4 inch on top of that. Nobody suggested taking out the 1/2
inch subfloor, which is good because I have no intention of doing so.
But I certainly dont need 3 layers.

You're dicking around with trying to improve something that is
substandard. Don't. Bite the bullet and just put down a 3/4"
subfloor on top of what you've got, then it doesn't matter what you've
got and you don't have to worry about attaching the layers. The price
difference is small and the savings in not having to mess around with
underlayment nails and worrying about attaching two layers is
obviously worth it.

"Screws are just plain out of the question"...? *Why?

Because after reading about the pros and cons I decided I'm not using
screws. I might shoot one in here and there
if necessary.

Cons? Okay, other than a worthwhile bump up in cost, and taking a bit
more time, name the cons.

*It's a superior

installation, doesn't cost a hell of a lot more, and unless you're
doing an entire house won't take all that much more time. *Even if you
are doing a whole house, the superior installation is worth the time
and money. *Rent an autofeed screwgun if you're worried about the
time.

If you are going to use nails, you should know what nails do, and how
they are supposed to work. *Underlayment nails, and roofing nails, are
designed to penetrate completely through the wood sheathing. *They
hold much better that way and are far less likely to back out over
time.

I have read the exact opposite. They should not penetrate the
subfloor. That was posted above and I have read it in other places. I
have also read the opposite, but since nails penetrating the subfloor
will splinter (or chip) the bottom and reduce holding power it seems
wise to me not to penetrate it completely if possible. I may not have
a choice though, if I use 5/8 plywood and nails.

Yeah, you read. There's a lot of bad information out there, and you
went and got yourself some. Attaching underlayment is essentially the
same as attaching roof shingles, and the nails are intended to perform
similarly. Plywood does not have the nail holding power that solid
sawn lumber does. If you had an old-school shiplapped subfloor, 3/4"
to 7/8" thick, then the underlayment nail doesn't have to penetrate
fully. You don't, so they do.

SBC further specifies that fasteners
for asphalt shingles be "minimum 12-
gauge (0.105-inch [2.67-mm]) shank
with minimum %-inch [10-mm] di-
ameter head, of a length to penetrate
through the roofing materials and a
minimum of % inch (19 mm) into the
roof sheathing. Where the roof sheath-
ing is less than % inch (19 mm) thick,
the nails shall penetrate through the
sheathing."

R