Reparing Subflooring 101

[Baron]

I am replacing a couple sections of subflooring for a bathroom project.

The original subfloor is OK -- it's the 1/2" subflooring sitting on top of the original that I am replacing.

My questions:

1. What type of fasteners would be the best? screws, nails, staples?

2. Do I need to add adhesive between the 1/2" subfloor and the original subfloor? e.g. Liquidnails

3. What is the recommended spacing for the fasteners?


Thanks.

[jadnashua]

The original needs to be well attached to the joists...if it isn't when you have the top layer off, fix that.

The top ply layer should cross the joists, not be parallel with them, for maximum strength. Screw into the subfloor, not the joists - this helps decouple the two layers. There's a good article on this over in the 'Liberry' (sic) at www.johnbridge.com where they specialize in tiling. Even if you aren't going to tile, it will tell you the proper way to minimize deflection and therefore squeaks.

[Baron]

The top ply layer should cross the joists, not be parallel with them, for maximum strength.

I did see a good article with parallel vs perpendicular on www.johnbridge.com.

Didn't see anything on recommended fasteners and spacing -- I'll keep looking.

[jadnashua]

6" on center is a good wag.

[econguy]

Google "plywood underlayment apa". The first result has a fastener guide for installing the 1/2" ply underlayment. It calls for a lot though...every 4" on the edges and 6" grid in the field will be about 128 nails per 4x8 sheet.

[Baron]

Thanks guys.