How to screw subfloor to joists

pick1e

I'm in the process of replacing the flooring in our dining room. Right now it's stripped down to the subfloor which is 1x12's on a 45 degree angle.

I'm thinking that I should screw down the planks with deck screws to reduce the movement and squeaking while I have the opportunity (I had to pound down quite a few loose nails).

Has anybody done this before? I'm wondering how many screws to use, and where? Right now there are three nails across each board into each joist. Should I use two screws centered between the nails or three screws- one close to each nail? I'm thinking that instead of trying to find the squeaks I should just go ahead and screw all of them down and be done with it. Okay, maybe a little OCD...

Just Bill

Screws in those OLD underlayment boards may split them. My choice would be nailing with a neumatic nailer, air or airless. They use cement coated nails that hold very well over time.

Ron6519

Which that width of board, I'd put 2 screws between the nails. Put them in snug, but don't over drive them. As Bill said, they may split.

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gregzoll

That is basically what I did, when I redid my bath. Went through and secured the sub-flooring, before putting down the dens-shield for the tile. I did not have problems driving decking screws in to secure. No boards split, no pre-drilling. Just have to use the proper sized screw.

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WillK

You could always pre-drill to reduce your chances of splitting boards, the most efficient way is if you have 2 drills and keep your drill bit in one and the screwdriver in the other. There are drill bits for this purpose that will put in a countersink in the same operation.

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Please do NOT consider any "before" picture of my house as any kind of endorsement of any particular construction method. In fact, you should probably assume that if I post a "before" picture, I am posting it because I am soliciting advice on a proper replacement for one of MANY things done wrong by a previous owner.

DexterII

Wow, what a pain that would be! But yup, my own house, that is what I would do. I would start with a straight drill, and see how that worked, then, depending on how dry those 1x12's are, the head may even split them when it is drawn down, in which case I would countersink them from there on. But I wouldn't drive any more of the old nails down. As you're working on it, others will undoubtedly pop up, at which time I would pull them out. They're likely 8 pd, in which case you could either replace them with 10 pd cement coated or screws.

pick1e

Thanks for the input guys. Yea I thought about pulling the popped nails and putting screws in their place- right after I finished hammering them all down

I'm actually more of a woodworker than a construction guy, so I believe I can put them in without splitting the planks. I have a quick-flip bit set for drilling, countersinking, and driving. So I'll definitely be using that. If the consensus is two screws equidistant between the three nails that's how I'll proceed!

Thanks again guys!

woodworkbykirk

yes the boards can split if the screws are overdriven... drill a pilot hole.. yes you can do that but it will double the time it takes to do it.. buy self tapping wood screws. it drills its own pilot hole as it goes in. regular wood screws wont self tap so you'll need to buy deck screws

pick1e

I ended up using SPAX self drilling construction screws #8x2" Torx drive. They went in like a hot knife in butter. These were about the same price as deck screws but I find the pilot/thread cutting is better and I didn't need coating. The wood was soft enough that I didn't need to drill pilots in most of the holes. I did drill pilots at the board ends and near imperfections like knots. It only took me about an hour and was worth it, there are no creaks and the floor even feels sturdier. There were a handful of spots where I could actually see the head pulling the plank down tighter to the joist.