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The standard for floor decking (over crawl space) in my area is 3/4″ tongue-and-groove “sturdifloor.” Familiar with it? I’ve had a friend suggest that I use 3/4 T&G “hi-density waferboard” instead. He says sturdifloor can delaminate if you get any significant moisture on it before you get a roof over, and the waferboard doesn’t. But it looked like the waferboard on the house he’s working on had “raised” edges at the joints? What do you think?
Also my framer says he doesn’t glue his decking (as many in this area do) because even a little moisture (dew) will prevent it from sticking properly. He says it can actually cause the floor to have a “squishy” sound. He just recommends that I come back and put a drywall screw between each nail he puts down. Again, what do you think?
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Rusty,
I like plywood for a lot of reasons and it sounds like you have a lazy framer. If he honestly feels that way, which I doubt, why doesn't he put those screws in?
JMO
Red dog
*Not sure what you mean by "hi-density waferboard". Sounds like you are referring to OSB. In any case, if you are using nail down hardwood flooring, check on the compatibility between that and the subfloor you want to use. Same thing goes if you will be having ceramic tile installed. Also use the Breaktime Search function to look for "Advantech". It is a relatively new product, but I have seen it to be a good alternative to OSB. Doesn't have the "swelling" problems of OSB or the delamination problems of plywood that are associated with exposure to wet weather.If you are going to screw down the floor, don't use drywall screws. They are made of low quality metal and snap off too easily. Rather, use deck screws, or an auto feed screw gun with the compatible screws. You can rent 'em. Personally, I would insist on glue. Approach it like this: "How much extra is it gonna cost me for you to glue the subfloor." Have the glue on site on framing day 1.
*I used 3/4" ply and repeatedly got it wet, luckily no problems except some swelling the belt sander will take out. I did clean up any standing water. I'm sure the OSB (the strongest form of the waferboard family) would perform well too, and it is likely to give you better density. (Sturdifloor may have some voids .. I happened to get mine cheap, or I would likely have used OSB.) I have a sneaking suspicion that not all ply or OSB of a given thickness is equal in quality. I had some 3- and 4-ply nominal 1/2" plywood that got wet; the 3-ply was destroyed and the 4-ply couldn't have cared less. Pretty good deal for the extra $2.Fastening -- I used glue (PL premium) on CLEAN, dry joists and 2 1/2" steel screws (McFeelys.com). The adhesive actually reacts with water to cure. The McFeely's screws are self-drilling, self-countersinking, which makes screwing faster, and very sharp & strong -- I start them into the subfloor with a framing hammer. The point of the glue is to stop squeaks. No nails or drywall screws.
*I use 3/4" OSB almost exclusivly and yes there is a difference in quality. OSB manfactured by Grant is far and away the best ( even if it is a Canadian import ). Most of the edge swelling that occurs is due to not leaving an 1/8" gap at all edges. I bought a Quik-drive screwgun a year ago and would never go back to just nailing. I would also insist on the glue.
*I believe AdvanTech is what I'm talking about. The guy showing it to me said it was "waferboard" as opposed to OSB. Sounds like a good product, but I wonder about nail holding ability when putting hardwood over it.
*I started using Advantech when it was introduced to my area (North Eastern PA.) about nine months.ago. I swear by the stuff. I put an addition up and after the deck was up, the client wanted a steeper pitch roof, and the structure was exposed for three weeks (while i waited for the trusses to arrive). In that time, we recieved over 6 inches of rain, and I never had a problem. Because the floor wasn't poured in the basement, there was no center post to sopport the LVL's, and I had an inch of standing water in the center of the deck. Again, no problems.As for the glue, I follow the always rule: always glue your subfloor. I also use 10 or 16d nails to run the floor down, then go back on a rainy day and screw the floor down with 2" teflon coated sq. drive screws. I have never had a problem or concern with Advantech holding nails for the finish floor (either strip hardwood or nailing of concrete backerboard). It seems that if this product doesn't swell like regular OSB (aside from normal expansion) that it is more stable than other choices, and less likely to pose a holding power problem.I hope that this is helpful.
*I have totally given up on using plywood if there is a chance it will get wet. I've had too many bad experiences with it. I use OSB exclusively. I don't ever have to worry about it. It is MUCH, MUCH more durable than any plywood. When the home is ready for the flooring, I go rent a floor sander for $20 and get one sheet of 20 grit paper ($5). I sand all joints and sand the entire floor wherever I will be installing tile backer over the OSB. This whole process takes me less than 2 hours for a typical 2500 sq. ft. home. I recommend sanding the joints like this no matter what you use for subflooring. It makes a much smoother surface no matter what you put over it.
*The sturdifloor that most framers use around here is 1 1/8" thick T&G plywood. I haven't seen the waferboard products used here for flooring. Always glue and screw.......always.Ed. Williams
*we've always (25 years) used 3/4" T&G, P&TS, cdx ply,and we're real slow.... and it always rains on our subfloor... and it has never delaminated or swelled or buckled.. we always glue .. and we always use glue that says it likes being applied on ice, water and wet wood, cause that's what we get....i can go back to the houses built under the worst conditions and check any glue joint, and everything is like day one.. good bond, no squeaks.. we always nail our decks with 8d common..that said.. from now on we'll be using Advantech until further notice, ..... glued and nailed..... and yes , he's either lazy.. er igerant....er both, Hah, hahb but hey , whadda i know..Kermit
*Always use glue! There are glues that will bond to wet and frozen lumber. I use OSB all the time and love it. We have learned two techniques that help keep us from experiencing the potential negative aspects of OSB. One is to keep a good gap (3/16) between the rows (do not drive the tongue and grove tight). The second is to coat all the butt end joints (the side joints) with a thin bead of glue and trowel smooth with a scrap of wood. The edges cannot swell then because they are sealed. If there is any edge swelling a quick belt sand gives you a nice level surface. Haven't tried Advantec yet but will be soon.