I'm installing 5/8' underlayment over a 1/2" subfloor. I've seen
contradicting info on how to orient the underlayment. Some say right
angles to the subfloor, but some say right angles to the joists. I
cant have it both ways, since my subfloor was installed at right
angles to the joists. What to do? My previous underlayment (which I
removed) was laid across the joists so unless I can find a compelling
reason I guess I'll redo it that way.

Also, I want to use nails. Screws are just plain out of the question,
and I dont want the expense of renting or buying staple equipment. But
the shortest ring shank underlayment nails are 1 1/4", which means
every one will be punching a hole and splintering out the bottom of my
subfloor, which is not desirable. I know they make 25 mm (1 inch)
underlayment nails but I cant find them in the US (or Canada, so
far)..

What to do?

On Wed, 14 Oct 2009 17:09:19 -0700 (PDT), Joe
wrote:

I'm installing 5/8' underlayment over a 1/2" subfloor. I've seen
contradicting info on how to orient the underlayment. Some say right
angles to the subfloor, but some say right angles to the joists. I
cant have it both ways, since my subfloor was installed at right
angles to the joists. What to do? My previous underlayment (which I
removed) was laid across the joists so unless I can find a compelling
reason I guess I'll redo it that way.

Also, I want to use nails. Screws are just plain out of the question,
and I dont want the expense of renting or buying staple equipment. But
the shortest ring shank underlayment nails are 1 1/4", which means
every one will be punching a hole and splintering out the bottom of my
subfloor, which is not desirable. I know they make 25 mm (1 inch)
underlayment nails but I cant find them in the US (or Canada, so
far)..

What to do?



How long will a 1 inch nail hold a 5/8" material?

Oren wrote in news:kgqcd5psggthgm97jjpi7hq7ka4m4ut8j8@
4ax.com:

On Wed, 14 Oct 2009 17:09:19 -0700 (PDT), Joe
wrote:

I'm installing 5/8' underlayment over a 1/2" subfloor. I've seen
contradicting info on how to orient the underlayment. Some say right
angles to the subfloor, but some say right angles to the joists. I
cant have it both ways, since my subfloor was installed at right
angles to the joists. What to do? My previous underlayment (which I
removed) was laid across the joists so unless I can find a compelling
reason I guess I'll redo it that way.

Also, I want to use nails. Screws are just plain out of the question,
and I dont want the expense of renting or buying staple equipment. But
the shortest ring shank underlayment nails are 1 1/4", which means
every one will be punching a hole and splintering out the bottom of my
subfloor, which is not desirable. I know they make 25 mm (1 inch)
underlayment nails but I cant find them in the US (or Canada, so
far)..

What to do?



How long will a 1 inch nail hold a 5/8" material?


1 x 5/8 x 12mo = 7.5 months.

On Oct 14, 7:19*pm, Oren wrote:
On Wed, 14 Oct 2009 17:09:19 -0700 (PDT), Joe
wrote:



I'm installing 5/8' underlayment over a 1/2" subfloor. I've seen
contradicting info on how to orient the underlayment. *Some say right
angles to the subfloor, but some say right angles to the joists. I
cant have it both ways, since my subfloor was installed at right
angles to the joists. What to do? My previous underlayment (which I
removed) was laid across the joists so unless I can find a compelling
reason I guess I'll redo it that way.

Also, I want to use nails. Screws are just plain out of the question,
and I dont want the expense of renting or buying staple equipment. But
the shortest ring shank underlayment nails are 1 1/4", which means
every one will be punching a hole and splintering out the bottom of my
subfloor, which is not desirable. I know they make 25 mm (1 inch)
underlayment nails but I cant find them in the US (or Canada, so
far)..

What to do?

How long will a 1 inch nail hold a 5/8" material?

I'd guess about exactly as long a 1 1/4 inch nail that chips out 1/8"
of the 1/2" subfloor.

On Wed, 14 Oct 2009 18:40:54 -0700 (PDT), Joe
wrote:

On Oct 14, 7:19*pm, Oren wrote:
On Wed, 14 Oct 2009 17:09:19 -0700 (PDT), Joe
wrote:



I'm installing 5/8' underlayment over a 1/2" subfloor. I've seen
contradicting info on how to orient the underlayment. *Some say right
angles to the subfloor, but some say right angles to the joists. I
cant have it both ways, since my subfloor was installed at right
angles to the joists. What to do? My previous underlayment (which I
removed) was laid across the joists so unless I can find a compelling
reason I guess I'll redo it that way.

Also, I want to use nails. Screws are just plain out of the question,
and I dont want the expense of renting or buying staple equipment. But
the shortest ring shank underlayment nails are 1 1/4", which means
every one will be punching a hole and splintering out the bottom of my
subfloor, which is not desirable. I know they make 25 mm (1 inch)
underlayment nails but I cant find them in the US (or Canada, so
far)..

What to do?

How long will a 1 inch nail hold a 5/8" material?

I'd guess about exactly as long a 1 1/4 inch nail that chips out 1/8"
of the 1/2" subfloor.


I'm sorry as I'm not certain what you mean by "chips out".

Dangling attic roofing nails can get your suspenders caught on the
nail or a hole-in-the-head. Those nails splinter the wood.

On Wed, 14 Oct 2009 18:40:54 -0700 (PDT), Joe
wrote:

How long will a 1 inch nail hold a 5/8" material?

I'd guess about exactly as long a 1 1/4 inch nail that chips out 1/8"
of the 1/2" subfloor.

Sorry, I cannot accept that.

"Joe" wrote in message
...
I'm installing 5/8' underlayment over a 1/2" subfloor. I've seen
contradicting info on how to orient the underlayment. Some say right
angles to the subfloor, but some say right angles to the joists. I
cant have it both ways, since my subfloor was installed at right
angles to the joists. What to do? My previous underlayment (which I
removed) was laid across the joists so unless I can find a compelling
reason I guess I'll redo it that way.

Also, I want to use nails. Screws are just plain out of the question,
and I dont want the expense of renting or buying staple equipment. But
the shortest ring shank underlayment nails are 1 1/4", which means
every one will be punching a hole and splintering out the bottom of my
subfloor, which is not desirable. I know they make 25 mm (1 inch)
underlayment nails but I cant find them in the US (or Canada, so
far)..

What to do?




First of all I don't consider 5/8" over 1/2" to be under-layment at all.
That is called a floor. Half inch is nothing.

Under-layment is something you put down to provide a smooth clean surface
for tile or vinyl and can be run either way. Usually it 1/4" and added to at
least a 3/4" sub-floor.

I would install it with the 8' running across the joist and try my darnest
to hit the joists. I would stagger the seams so that the new does not line
up with the old on either direction. I would use a minimum of 8D sinkers to
secure it. Now you have a floor.

To minimize potential squeaks I would use a single layer of 30# felt or a
double layer of 15# felt. Alternately you can use liquid nails or the like
in lieu of the felt.


--
Colbyt
Please come visit www.househomerepair.com

"Colbyt" wrote:

-snip-

First of all I don't consider 5/8" over 1/2" to be under-layment at all.
That is called a floor. Half inch is nothing.

Under-layment is something you put down to provide a smooth clean surface
for tile or vinyl and can be run either way. Usually it 1/4" and added to at
least a 3/4" sub-floor.

I would install it with the 8' running across the joist and try my darnest
to hit the joists. I would stagger the seams so that the new does not line
up with the old on either direction. I would use a minimum of 8D sinkers to
secure it. Now you have a floor.

To minimize potential squeaks I would use a single layer of 30# felt or a
double layer of 15# felt. Alternately you can use liquid nails or the like
in lieu of the felt.

What he said. Though he didn't make clear that all those 8D nails
go into joists.

*THEN* you put your 1/4 subfloor in if you need it and use the short
ring nails.

Jim

On Oct 15, 5:52*am, Jim Elbrecht wrote:
"Colbyt" wrote:

-snip-





First of all I don't consider 5/8" over 1/2" to be under-layment at all.
That is called a floor. *Half inch is nothing.

Under-layment is something you put down to provide a smooth clean surface
for tile or vinyl and can be run either way. Usually it 1/4" and added to at
least a 3/4" sub-floor.

I would install it *with the 8' running across *the joist and try my darnest
to hit the joists. *I would stagger the seams so that the new does not line
up with the old on either direction. I would use a minimum of 8D sinkers to
secure it. Now you have a floor.

To minimize potential squeaks I would use a single layer of 30# *felt or a
double layer of 15# felt. Alternately you can use liquid nails or the like
in lieu of the felt.

What he said. * * Though he didn't make clear that all those 8D nails
go into joists.

*THEN* you put your 1/4 subfloor in if you need it and use the short
ring nails.

Jim

I already have a subfloor. The subfloor goes on the joists.
Underlayment goes on top of the subfloor.

On Thu, 15 Oct 2009 07:49:33 -0700 (PDT), Joe
wrote:

On Oct 15, 5:52*am, Jim Elbrecht wrote:

-snip-

*THEN* you put your 1/4 subfloor in if you need it and use the short
ring nails.

Jim

I already have a subfloor. The subfloor goes on the joists.
Underlayment goes on top of the subfloor.

Brainfart- sorry. I meant underlayment. I don't consider 1/2 ply
to be anything more than a waste of time. 5/8, maybe-- but I
wouldn't do less than a couple layers of 3/4. I'd even prefer
shiplap for that first layer over the joists. Then 3/4 T&G to
smooth things out.

Jim

On Oct 15, 10:49*am, Joe wrote:
On Oct 15, 5:52*am, Jim Elbrecht wrote:
"Colbyt" wrote:

First of all I don't consider 5/8" over 1/2" to be under-layment at all.
That is called a floor. *Half inch is nothing.

Under-layment is something you put down to provide a smooth clean surface
for tile or vinyl and can be run either way. Usually it 1/4" and added to at
least a 3/4" sub-floor.

I would install it *with the 8' running across *the joist and try my darnest
to hit the joists. *I would stagger the seams so that the new does not line
up with the old on either direction. I would use a minimum of 8D sinkers to
secure it. Now you have a floor.

To minimize potential squeaks I would use a single layer of 30# *felt or a
double layer of 15# felt. Alternately you can use liquid nails or the like
in lieu of the felt.

Squeaks come from the wood sliding against the nails, not from the
underlayment sliding against the subfloor.

What he said. * * Though he didn't make clear that all those 8D nails
go into joists.

*THEN* you put your 1/4 subfloor in if you need it and use the short
ring nails.

Jim

I already have a subfloor. The subfloor goes on the joists.
Underlayment goes on top of the subfloor.

Thanks for the definitions. He used the wrong word, so stop being a
smartass and learn something.

"Screws are just plain out of the question"...? Why? 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. If you are concerned about the appearance from below (you like
the look of exposed 1/2" CDX???), then you should look into nailing
just at the joists, glue the underlayment down and weight it so there
are no gaps between the two layers.

R

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.


"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.

*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.

"Joe" wrote in message

Also, I want to use nails. Screws are just plain out of the question,
and I dont want the expense of renting or buying staple equipment. But
the shortest ring shank underlayment nails are 1 1/4", which means
every one will be punching a hole and splintering out the bottom of my
subfloor, which is not desirable. I know they make 25 mm (1 inch)
underlayment nails but I cant find them in the US (or Canada, so
far)..

What to do?

I think you're screwed. Neihter McFeelys nor McMaster have them so they will
be about impossible to find. I'd buy or rent a stapler. Or go with screws.

http://www.halexcorp.com/halex_underlayment_3.shtml

Fasten the plywood underlayment panels securely to a structurally sound,
smooth, clean and dry subfloor using;

a.. Staples: galvanized or polymer coated 18 gauge chisel point staples
with minimum 1/4" crown or,

b.. Galvanized ring shank flooring nails: 12 gauge, minimum 3/16" diameter
head or,

c.. Galvanized flat head wood screws.
Fasteners should be long enough to penetrate through the plywood
underlayment and atleast 80-95% of the subfloor, but not protrude through
the bottom. Fasten one plywood underlayment panel at a time, starting from
one side and working to the other. Do not lack the corners first. If using
staples or nails, fasten on every fastener mark (4" on center in the field
and 2" on center along all edges. Fasten edges 3/8" - 1/2" from the edge.
Fasteners should be set flush so they do not protrude above the plywood
underlayment.