Okay my poor husband is already SO frustrated with this project it's up to me to do the research.

We are planning to lay 1/2 inch oak engineered anderson floor, 3" plank, 42" long.

We have 1/2 inch subfloor (square edge, NOT T&G) on 16" spaced joists.

Over that we had particle board. Hubby is ripping up the particle board. At first we thought we could just go over the sub floor, but I realize now it's too thin.

So we need to lay plywood, but after reading this forum for hours I'm still confused.

The only thing I can find in CD at Lowes (hubby works there and gets discount) is T&G 23/32. I have read to NOT use T&G as underlayment.

They have a 1/2 inch DD grade. Would that work over the current 1/2 inch? It is $18/sheet.

I'm not worried about matching heights because we are doing the entire upstairs with the new floor (except bathrooms which are tiny and we can redo those.)

Once I know the right plywood: I also need to know how to lay. Should we run the new plywood parallel to the joists (opposite of subfloor) or the same direction as subfloor and stagger joints? Hubby wants to screw it down..is that okay?

Should we use any glue? He said something about liquid nails but I told him I thought that was a no no.

I also notice some of the subfloor has tiny spaces between the seems? Has it contracted or is it supposed to be like that to allow for expansion.

Please help! Hubby is trying to get this done and is getting frustrated at the setbacks and I want to be sure we do it RIGHT!

THANK YOU!!!!

I would go to a lumber yard rather than home depot to buy the stuff. Home Depot usually has inferior products. I would get at least 1/4" plywood since you need 3/4" and ask the lumber yard's advice on the type you should use...that way you will get the right item. You want to make sure there are plys in there/structure. (BTW, I usually find the prices at the lumberyard to be lower than Home Depot).

And, yes, the better way to do it is to nail + screw.

The hardwood should be nailed perpendicular to the joists, not the plywood. But, I might stagger the plywood on top of the subfloor that is there for better structure.

Debbie Gartner, aka The Flooring Girl
http://TheFlooringGirl.com
Westchester County, NY

Thanks for the reply!

Okay we ordered 42 sheets of 1/2 inch CDX to go on top of the current 1/2 inch CDX subfloor for a total of 1 inch.

We were able to borrow a pneumatic construction stapler from a contractor friend. I'm assuming we should use 1 inch staples since that is the depth of our floor??

He also recommened we liquid nails the edges of the underlayment together to avoid squeaks. Thoughts on that?

The current plan is to lay the new plywood perpendicular to the old plywood for added strength.

This is only phase 1 - installing about 1350 sq ft upstairs.

Phase 2 is installing about 550 feet of engineered glue down in the basement.

Phase 3 is redoing the foyer stairway and landing to match.

So much fun to come!

A few things to consider.

Make sure the existing subfloor is flat especially where the plywood sheets meet. Sand down if necessary. A flooring edger will work the best.

Overlap existing plywood (joints) sheets with new.

Staples? I'd use screws. They draw the plywood tighter eliminating potential squeaks. Adhesive? Wouldn't hurt.

Oh gosh, I need more sleep...I nail nail & screw...I meant screw & glue. Definitely get adhesive, too.

Debbie Gartner, aka The Flooring Girl
http://TheFlooringGirl.com
Westchester County NY

I had read elsewhere on this site to staple.

So what screws would you recommend for screwing? Hubby had thought about using drywall screws but not sure if we should use those or decking screws.

Thanks!

best thing is the deck screws that are correlated.

How come when I punch in 3" engineered oak on Andersons site nothing comes up? Are you floating the floor or nailing it?

We are nailing (we got a bostitch flooring stapler) This floor was actually a promo item. ..not part of their regular line.

screws are better for the subfloor but will take much longer, nailing is fine along with the adhesive.