Is it worth screwing down an OSB floor?
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I’m an homeowner, in the middle of building a 2 story+finished basement house. I want the house to be as quiet as possible, so I’m adding insulation in the interior walls and ceilings (extra$, but I think well worth it)
The floors are TJI with OSB, glued and nailed. The builder can also screw down the floors for a few hundred $ extra. In line of principle, I’d like to do whatever I can now, to assure quiet and squeak-free foloors/ceilings for years to come.
Is it worth the extra cost? Would screws make a difference, over the existing glue and nails?
Thanks in advance, Rob
Replies
Rob,
1st, when you say osb flooring are you talking about standard grade osb t&g subfloor or an Advantec type sheathing? I wouldn't recommend the standard grade osb myself. We use either advantec or GP's commparable sheathing. I've used both nails and screws. Screws do tend to suck things together a little tighter, but I'd be more concerned about using the best glue you can find. We've started using a polyurethane based floor glue that seems to work great, called PL premium. It's a little tough to use when the weather gets cold, but other than that, it's great stuff.
Bish
I keep a heat gun plugged in for the PL and caulking, a minute or two on high setting gets you going again.
mike
If it is already glued properly and nailed with ring shank nails, there is no benfit in screwing it down now.
But as mentioend, if you have regular OSB and not Huber Advantech, you will be wanting another ply of underlayment. Especially if it is only 5/8" That would be a good time for glue and screws too.
So, what have you got and hoiw thick is it?
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Thanks everybody for the comments.
The floors are already in place (house is ready for insulation and drywall). The builder used T&G OSB Gold Edge, 3/4" (the framers, when they saw the pallets, commented something along the lines of "the good stuff", for whatever is worth :-). In the Seattle area Advantech doesn't seem to be available
The boards have been nailed with standard nails (the same nails used everywhere else, as far as I can tell).
The few areas where there's tile, there will be cement board underlayment. Some areas are hardwood (site finished), the whole upper floor (minus the baths) is carpeted. No additional underlayment is planned
I'd screw them even if they were nailed.
Screws by themselves, with no glue will hold the osb tight and will be silent. Many of the builders that we've built for screw the floors just prior to carpet. If any squeaks have developed, the screws silence them.
blue
That's agood point abnout waiting to screw when ready to ccover with the carpet to see where squeeks develope. The only place it would nbe necessary is if the glue job was bad, say if they did it on cold wet day and dirty lumber.
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yep
Spheramid Enterprises Architectural Woodworks
"Yup, I really bought this place, wanna shoot me? Please?
If it is properly glued and nailed there is no advantage to screwing. Since you are using tji joists I will add that you will get floor squeaks from any areas where there are joist hangers. That is unavoidable and is the reason that I really hate using those crappy things.
Just a small thing, try to find "Underlayment nails" for subfloor if you choose to nail. They are a ring shank, but have a different shaped, beveled head that helps them seat in the floor easily. It helps so you dont have to go around later and find the raised heads, or have big hammer divots.
-zen
I've done quite a few with TJIs in hangers and no squeeks. Gotta cut and nail right. It is when the joist is allowed to slide in the hanger that it can squeek
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I was taught to put a dab of adhesive in the bottom of floor joist hangers as an added precaution against squeaking. (and I'd better cut them tight or else!)
Then it looks like my joist hangers were done properly :-) they all have plenty of glue, and are really tight, with no really visible gaps
Thanks for the input. I was on the fence, and your input helped sway me in the "screw it" direction (errm, somehow that doesn't sound quite the way I intended it :-)
Mark,
Like the actress said to the bishop, "If it squeaks, you're not doing it right."
TrusJoist techs recommend glue in saddle of hanger and a single screw up from below into bottom chord. Trying to toenail the joist's upper chord is typically what causes squeaks. Unnecessary to secure top chord of TJ into hanger as sheathing will do that anyway.
WallyLignum est bonum.
Definately glue in the bottom of hanger. And any good builders/GCs around here are paying their labour guy to put that bottom screw in the hanger, and screw the floor down. Typically we glue and staple the floor with 2" staples. (staples 'cause it's machine gun fast) Then later the builder gets it screwed down. If we do happen to get a builder who's not screwing down then we use the nails. personally I like the screws.
It's been stated that you don't need to screw down sub-floor if it has been properly glued and nailed. Probably a true statement. But, screwing down the floor adds a margin for error just in case the glue and nails were not done in an ideal fashion or under perfect circumstances. In the real world, many things are less than perfect, and redundancy is helpful.
As an aside, you mention that you are insulating ceilings. I will share a cautionary tale about insulating around pipes. I added batt insulation around pipes in the ceiling in a 2-story house I had built to reduce noise from running/draining water. First really cold weather of the winter (below zero and windy), the trap under the master tub froze, as did some of the supply lines (all near an exterior wall). Turns out that my noise insulation was preventing warm air from the house to penetrate the floor/ceiling cavity and reaching the pipes. I suspect that a properly sealed and constructed house wouldn't allow enough cold air to penetrate the cavity that it would freeze pipes, insulation or no. But, once again, in the real world things are not always as they should be. In this case, my insulation removed any margin for error. I removed the batts, and the freezing problem went away.
I am constantly de-squeaking floors. I use screws. Sometimes there was no glue or it was applied during the rain or just a crap job to begin with. Always thought it better to drill a hole through the deck and plant the screw right into the joist. Sometimes the dried glue prevents the nice tight clamping effect a screw normally gives. But is usually better than the way I found it. If the deck is held with bright box nails and a poor glue job prepare for an assault on your ears. Ringshanks are MINIMUM. Wood dries. Grip loosens. Squeaks start.
If a hardwood floor the squeak could be from the deck nails or from the hardwood nails. If the basement ceiling isn't finished a wedge can stop the deck squeaks (for awhile). I have recessed screws in the hardwood (usually oak) by drilling with a 3/8" bit first, then a 3/16" for the screw. Takes a piece of oak dowel to fill the 3/8" hole, trimming, sanding and finishing (usually the whole floor). Not fun for a few squeaks.
You could also use some accoustical channel instead of interior insulation (or both) to deal with the sound. Be sure 5/8" gypboard goes on the ceiling (minimum). Two layers of 1/2" installed perpendicular to each other (longer drywall screws) really help the sound. As a walking surface I would have glued and screwed the decking from day one instead of correcting things now. You should buy the screws and the GC should "correct" the problem at no charge to you. If you are the GC--you are on the right track. Do it now. Tyr