As a long time lurker and occasional contributor to this group I
realize this may not be the correct to post this message but I'm going
to do it anyway. :-)
I'm a competent amateur woodworker,
have done my fair share of home renovation projects but I've never
installed hardwood flooring before. I've read up on it on a few web
sites and perused the flooring book from the Borg and in all cases
they suggest runing the flooring strips at right angles to the joists.
Esthetically, this will not work in our house.
The current subfloor is 3/4" osb and is in ok condition. I read
someplace that to install the flooring parallel to the joists an extra
1/2" plywood layer would be a good idea. Is this necessary or is is
Rule of thumb I was taught is it takes an 1 1/2 inch subfloor to keep
ceramic tile from turning into dust, that said I think that even if you add
the subfloor to build up to 1 1/4 I'm betting the floor would have some
waves in it after some time. Maybe if you had access to the joists
underneath you could add some solid blocking?
The reason to run perpendicular is for the joist to bear the load. Is it
over kill? Wait until you unload 300 sq.feet of 3/4" flooring and get a
real feel for what is going to weight! We actually stacked some of our wood
flooring boxes PARALLEL to the joists (like your proposed installation) and
the plywood underfloor bowed and flexed! We re stacked perpendicular.
Overkill- no. Architecturally correct- yes.
OSB is an unsuitable substrate for hardwood floor; doesn't hold the
nails. An additional layer of plywoood is not only a good idea but
necessary. Screwed and glued. 3/4" would be better in your
application. Check the osb for flatness first.
Definitely not overkill. Even if you were installing perpendicular to
the joists, you should probably put down the extra 1/2" plywood. OSB
does not hold nails well and when I was researching installation of
flooring, all the advice I received said I needed at least an extra
1/2" of ply. I installed my pre-fin flooring at a 45 degree angle to
the joists. Other than adding some extra subfloor, the installation of
prefinished floor is a breeze.
Look at http://www.nofma.org/installation.htm (NOFMA: The Wood Flooring
they state that 3/4 OSB is an acceptable subfloor. They dont
specifically say it's ok to go parallel to the joists with that, though.
I think it would be wise to add the plywood if going parallel to the
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