What type of fastener should I use for installing 3/4" plywood on top of floor joists? Should I use screws or nails? What type? What length? And what spacing?

I plan to use 2" deck screws and some sub floor glue with 5 screws per middle joist and 8 screws one the plywood ends. Is there any problem with that?

 

I'm no pro but that sounds right on target. I would use screws; they don't work loose. Might check out APA site for more technical info:
http://www.buildernewsmag.com/viewnews.pl?id=329
also; a lot of info at:
http://www.gp.com/build/literature.aspx
Bob

 

If you use a good subfloor adhesive, it won't really matter about the fastener, as the adhesive will be your major holding agent. I use galvanized ring shank #8 nails spaced about every 8 inches, but using the screws will work just fine, just a lot more work. It is your project, so it is your call. Good luck with the install and let us know if we can help further.

 

Most of the quality home builders in my area use Grabber Screws and a Superdrive collated screw gun for a speedy installation. The C8175L3YZ is a #8 by 1-3/4" zinc coated fastener and is the screw of choice. Along with some GSFA subfloor adheasive you will have no squeaks. Go to www.grabberman for more info.

 

In preparation of install tile in my house I have discovered that the subfloor consists of two layers -- 3/8-inch bc plywood and 3/8-inch particle board, 3/4-inch total depth. In replacing the particle board can I use 3/8-inch bc plywood, glued and screwed to the first layer --- would like to retain same depth of subfloor? The floor joists are 2/10 on 12-inch centers with every third joise doubled.

Thanks in advance

 

You can use 3/8" plywood glued and screwed to the joisting, not to the original plywood only. And you have to turn the plywood 90 degrees to the original install, starting in the middle on a joist and running outwardly so you are hitting a joist with all the joints. Are you going to be tiling or laying hardwood over this?