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I’ve not installed one.
(and I’m not planning to).
Every one I’ve seen done has had a layer of felt between the subfloor and the oak.
That was out west.
The contractor I’m working with here in Nashville says he’s never seen anyone lay felt before the oak (or maple…).
Seems to me it’s a moisture barrier.
What gives?
What about CDX vs OSB for a substrate? Does it matter?
Dan
Replies
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Dan,
I use red rosin paper instead of the felt. I think it acts more as a slip sheet between the floor and subfloor then as a vapor barrier.If your worried about moisture migration up from a crawl space or bathroom i think the vapor barrier should go on the other side of the framing.
As far as the subflooring goes I've never really liked OSB for anything so I would have to say CDX or something like Sturdifloor t+g would be best. I do remember reading an article a long time ago that gave the relative holding powers of CDX vs. OSB vs. planking...and if I recall correctly the planking came out on top followed closely by the CDX. Hope this helps.
Richard Max
*Hi Richard,Just curious. Are we talking about t&g flooring? If so, how do you clamp up the boards with paper under?Regards,Mark
*I've always seen the pros use red rosin paper and I also understand it to be a slip sheet. It allows the hardoowd to expand and contract and I guess minimizes squeeks. In some installations it may also keep dust from migrating between floors (but that's more an issue with t&g or butt jointed sub-floors... in the days befor plywood sub-floors were 3/4 t&g layed diagonally to joists... there was an FHB article years back about t&g material used as second floor subloor and exposed first floor ceiling, that's the reference I think to a dust issue that I remember.I don't understand the question about clamping. The way I've always done hardoowd floors over the paper is to nail through the tongues and paper into subfloor using a floor nailer. Most often the blow of the mallet sucks up any bow between boards. Sometimes they need to be persuaded and held in place. I've used a hydraulic jack with a piece of 2x to an opposite wall; or a block screwed to the floor to work a pry bar against.
*Dan, not sure about the clamping thing either, but we use felt for a squeak resistant floor. Rosin paper would probably do the same, but you wouldn't get that petroleum offgassing that we've come to knbow and love. I've always thought the vapor barrier should be laid over the crawl space dirt, or under the basement slab. Never even built close to the west coast. Oh yeah, ever tried to pull a nail out of OSB?No callbacks, BB
*DScott,All our floors are clamped before nailing. These are a clamp that lock onto the joist and then you can pull the boards up tight.Mark
*OK Mark, I think I've got the picture. Does that mean the hardwood floor goes directly down onto the joists with no subfloor? In that case the paper would get in your way.The typical installation I've seen is a 3/4" sub-floor (t&g in the old days, plywood since and sometimes newer options like OSB now; sometimes a second underlayment like Homasote for cushion/quiet) over the joists. This is part of roughing and closing in the house, it's the floor the trades walk on while installing interior partitions, mechanicals and drywall. The finish floor (hardwood, carpet, sheetgoods, tile, whatever) goes on over this towards the end of the job. So the joists are already inaccessible for clamping, the paper doesn't add to the problem (except you need to chalkline the joist lines on the paper if you need to know where they are).I think I mentioned in the earlier post that a different alternative - is to use the flooring as the exposed ceiling below. That's when I've heard the paper stops dust migration. That would create a problem with the clamping you describe.Scott
*Anyone take any special steps when laying new strip oak over 3/4" planking after removing the old strip oak that's been sanded to its demise?!I'll use the rosin paper as you guys mention and as I've done on jobs with new CDX subfloors but was wondering if the "swiss-cheesed" planking would be at all compromised to take a new floor with all its nails?