I have a situation in a 13yo townhouse (I own this one) where the first
floor has about 325 sq ft of 1/2" hardwood laminate coverage and
about 600 sq ft of carpet. Both rest directly on an OSB subfloor.

I want to replace the entire floor with 3/4" hardwood planks. This
is do-able because it will only raise the floor a net 1/4". However,
some of the contractors I've talked to insist that I need to lay
a 3/8" layer of plywood on top of the OSB before the new floor
is installed. Others say it's not important and that OSB is the
recommended subfloor for hardwood anyway.

I'd obviously like to avoid both the cost and pain of raising the floor
an additional 3/8" if I don't have to. But ... I also want this done
rights. So ... what is the wisdom of the Wreck on this one?

TIA,


P.S. There are some floor creaks, but at least one contractor told me
this was primarily an artifact of the floor joists and that adding
the additional layer of plywood would make little or no difference.
I wonder ...

--
----------------------------------------------------------------------------
Tim Daneliuk
PGP Key: http://www.tundraware.com/PGP/

On Fri, 19 Oct 2007 22:46:57 -0500, Tim Daneliuk
wrote:

I'd obviously like to avoid both the cost and pain of raising the floor
an additional 3/8" if I don't have to. But ... I also want this done
rights. So ... what is the wisdom of the Wreck on this one?

With 3/4" solid wood, across the joists, I'd go over the OSB. Parallel
to the joists, I'd probably add the ply. Other times I'd add any
sort of extra layer might be under linoleum, to prevent the OSB
texture from embossing, or tile, to remove some bounce.

Try to catch as many joists with the HW flooring nails as you can. I
usually shoot for the joists, with another nail midway between, using
2" nails in a PortaNails air nailer.

P.S. There are some floor creaks, but at least one contractor told me
this was primarily an artifact of the floor joists and that adding
the additional layer of plywood would make little or no difference.
I wonder ...

An extra layer could actually add more creaks, or eliminate them, I've
seen both results.

When you install the HW, be sure to drive home any popped subfloor
nails before you lay the paper. You can also tighten up any creaking
areas with a few drywall screws.

---------------------------------------------
** http://www.bburke.com/woodworking.html **
---------------------------------------------

"Tim Daneliuk" wrote

I'd obviously like to avoid both the cost and pain of raising the floor
an additional 3/8" if I don't have to. But ... I also want this done
rights. So ... what is the wisdom of the Wreck on this one?

Assuming that it is indeed tongue and groove "OSB subflooring", properly
installed and level, there should be no need to add an additional layer of
plywood subfloor prior to installing nailed down HW flooring.

Most of the houses I build are HW floors throughout, and the above is a
common practice on all second story HW floor installations.

--
www.e-woodshop.net
Last update: 9/30/07
KarlC@ (the obvious)

Contact the manufacturer of the wood floor that you intend to purchase and
ask their advice.



"Tim Daneliuk" wrote in message
...
I have a situation in a 13yo townhouse (I own this one) where the first
floor has about 325 sq ft of 1/2" hardwood laminate coverage and
about 600 sq ft of carpet. Both rest directly on an OSB subfloor.

I want to replace the entire floor with 3/4" hardwood planks. This
is do-able because it will only raise the floor a net 1/4". However,
some of the contractors I've talked to insist that I need to lay
a 3/8" layer of plywood on top of the OSB before the new floor
is installed. Others say it's not important and that OSB is the
recommended subfloor for hardwood anyway.

I'd obviously like to avoid both the cost and pain of raising the floor
an additional 3/8" if I don't have to. But ... I also want this done
rights. So ... what is the wisdom of the Wreck on this one?

TIA,


P.S. There are some floor creaks, but at least one contractor told me
this was primarily an artifact of the floor joists and that adding
the additional layer of plywood would make little or no difference.
I wonder ...

--
----------------------------------------------------------------------------
Tim Daneliuk
PGP Key: http://www.tundraware.com/PGP/

On Fri, 19 Oct 2007 22:46:57 -0500, Tim Daneliuk
wrote:

I want to replace the entire floor with 3/4" hardwood planks. This
is do-able because it will only raise the floor a net 1/4". However,
some of the contractors I've talked to insist that I need to lay
a 3/8" layer of plywood on top of the OSB before the new floor
is installed. Others say it's not important and that OSB is the
recommended subfloor for hardwood anyway.

I've seen hardwood floor installers install wood flooring on top of
OSB since OSB has been around. I've never seen them put anything on
top of the OSB (for wood flooring) except felt or that funny looking
foam paper. That doesn't make it right but that's all I've ever seen
done.

Mike O.

Folks,
Leon is REALLY correct. I had selected a flooring to put down, only to
find out from the manufacturer, that my choice would be disastrous. (
Radiant Heat floor) The point is the manufacturer is the one holding the
guarantee on the flooring. They have a vested interest in telling you what
will go wrong. BTW, most manufacturers have a web site you can post the
question to them. Then you have the reply in writing !!

Paul
"Leon" wrote in message
t...
Contact the manufacturer of the wood floor that you intend to purchase and
ask their advice.



"Tim Daneliuk" wrote in message
...
I have a situation in a 13yo townhouse (I own this one) where the first
floor has about 325 sq ft of 1/2" hardwood laminate coverage and
about 600 sq ft of carpet. Both rest directly on an OSB subfloor.

I want to replace the entire floor with 3/4" hardwood planks. This
is do-able because it will only raise the floor a net 1/4". However,
some of the contractors I've talked to insist that I need to lay
a 3/8" layer of plywood on top of the OSB before the new floor
is installed. Others say it's not important and that OSB is the
recommended subfloor for hardwood anyway.

I'd obviously like to avoid both the cost and pain of raising the floor
an additional 3/8" if I don't have to. But ... I also want this done
rights. So ... what is the wisdom of the Wreck on this one?

TIA,


P.S. There are some floor creaks, but at least one contractor told me
this was primarily an artifact of the floor joists and that adding
the additional layer of plywood would make little or no difference.
I wonder ...

--
----------------------------------------------------------------------------
Tim Daneliuk
PGP Key: http://www.tundraware.com/PGP/

In article ,
says...
On Fri, 19 Oct 2007 22:46:57 -0500, Tim Daneliuk
wrote:

I want to replace the entire floor with 3/4" hardwood planks. This
is do-able because it will only raise the floor a net 1/4". However,
some of the contractors I've talked to insist that I need to lay
a 3/8" layer of plywood on top of the OSB before the new floor
is installed. Others say it's not important and that OSB is the
recommended subfloor for hardwood anyway.

I've seen hardwood floor installers install wood flooring on top of
OSB since OSB has been around. I've never seen them put anything on
top of the OSB (for wood flooring) except felt or that funny looking
foam paper. That doesn't make it right but that's all I've ever seen
done.

Mike O.

Me,too. I installed more than 1500 t&g oak and maple and passed osb for
plywood, swallowing a significant extra cost because I thought it was
the right way to go. I have since seen more than a few installations
using osb.