Should I use plywood or T&G OSB for subfloor in new addition I am
building? The addition is on second story, floors are 2 X 8 16 O.C. I
checked prices and 3/4" T&G OSB is more than twice cheaper then 3/4"
plywood. I will have hydronic heated floors. There will be another
plywood or OSB subfloor on top of base one with grooves for PEX
tubing. My original idea was to use OSB everywhere except for bath
subfloor where I was going to use plywood.
My builder uses a product called
AdvanTech, which seems to be super
strong. It is T&G and comes with a 50
year warranty, whatever that means.
Here are a few pics taken in my house
I think that was the only OSB Lows had when I needed it for a floor. I
believe their was a 100 day exposed to weather guaranty but when I
bought mine I was told they raised that to 300 days out in the weather
without falling apart. The part that looks confusing is the smooth side
goes down, the rough side up.
They're basically interchangeable. Check the span ratings stamped on the
sheets to see what would work for your application. Standard plywood is
slightly stronger than OSB, which means you might need to use a thicker OSB
for the same application. But it really depends on the usage. In many cases
you can use either in the same thickness.
I used 3/4" T&G OSB for the subfloor of our house and it works very well
(16" OC joist spacing). I've heard it can be slightly more sensitive to
moisture during construction, but our subfloor was exposed to the weather
for a few months while we built our house, with no signs of swelling
anywhere. But we did sweep off the subfloor each day to remove any standing
water. If you think it will take you a long time to build, plywood might
be a better choice (or just cover everything with plastic).
Another thing to consider is weight. OSB is a bit heavier than plywood, so
I used plywood for our roof sheathing. It's not a huge difference, but I
appreciated the lighter sheets when I had to hoist them up to the roof
I used OSB sheathing for the walls of a remodel at my in-laws, since it was
being covered with siding anyway. For our own house we wanted a rough-cut
face which was only available in standard plywood at the time (though I did
buy an OSB version later for our shed).
I generally choose whichever is available at the lowest price that meets
the span and appearance ratings I need. In most cases, OSB works fine.
Maybe today's OSB is better than older material, but having removed a
lot of it from rehab projects, and replaced with plywood, it is no
longer anything I care to use. It is much heavier, meaner to cut, and
too rough surfaced for me. In addition, saw blades suffer early wear-
out and need to be sharpened or replaced too soon. Roof decking and
siding will often see nail blowouts underneath, and my unscientific
opinion is that OSB doesn't hold nails as well.
The resin rich character of OSB would, to me, be a real no no by
having a negative effect on the hydronic system. A heavy dense
material just doesn't seem right for that, but I may be totally wrong
OSB is slightly more expensive than plywood here, so I was planning on using
plywood for the room I'm building over the garage. I wanted to use plywood
anyway because I'm not planning on finishing the floor right away (it's going
to be used for a shop). Plywood, with a coat of floor paint, should be easier
to sweep clean than OSB. Before I sell, I'll turn the room into another
On 3/6/2010 2:55 PM,
The Advantech stuff I talked about
earlier and someone explained that is
was an OSB-type product has a very
smooth surface. It's nothing like the
OSB stuff you find at HD or Lowe's. It
seems to be much harder than the regular
OSB stuff. I know my builders
carpenters complained about how
difficult it was to drive nails or
screws. And, as was pointed out, it has
ratings for various spans, like 16" or
in my case 19.2".
Advantech is pretty much the material of choice around here even in high end
homes...It is on my addition and garage...As far as builders complaining
about "driving nails and screws" , I haven't heard that but I don't know any
builders that don't use nail guns...Even I as a homeowner have nail guns
now...Cutting plywood isn't any fun either...They BOTH suck about the same
in that regard..If you're going to paint it for a shop floor plywood would
be the best choice....FWIW....
My builder, even though he's a young
guy, has some "older" ideas. For
instance, he makes the carpenters hand
drive all the deck nails. I'm not sure
if the Advantech was put down with nails
or screws. I think it was grooved nails.
Come on. It's not *that* bad, in comparison with other building materials.
The sawdust from either is fairly large so you don't end up breathing it.
Plywood is easy on blades and I suspect OSB is about the same (haven't cut
enough to go through a blade). MDF is a lot worse than either and
Hardi-Backer dust is tough on both tools and operators' lungs.
Actually, I had T&G plywood in my
previous house circa 1971 and I can tell
you the squeaking was just as bad or
worse than anything I have seen. I
think, and that all it is, think, that
the tongue actually squeaks rubbing in
the groove. I re-nailed many places and
used those break off screws that go
through the carpeting to quiet things
down. When replacing the carpeting, you
know, for the potential new owners, I
put in a bunch of screws. I figured
that I would still be living there for a
time and I actually did for about 6
months until it was sold.
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