[RichardZ]

I gutted the kitchen in a condo unit I own. I've put up new drywall, and am now ready to tackle the floor.

The old finished floor was taken up, so I'm now down to the 5/8" plywood subfloor.

The floor squeaks. I plan on lifting up the plywood where I can (it's currently nailed), put down Loctite's PL 400 subfloor glue on the joists, and then re-laying the old plywood back in place, screwing it to the joists. I'd like to put down new plywood, but the ends of most of the sheets run under walls, so I plan on just lifting the "free end" and putting subfloor glue where I can. I'm not too worried about re-using the old plywood because despite the plywood being down for 50+ years, it seems pretty solid. (On the other hand, if someone thinks differently, please let me know!)

When I screw the subfloor to the joists, I plan on using 1-5/8" general purpose exterior screws. I'm planning on screwing these every foot, and screwing them into each joist under the plywood. Is this correct? Should I use deck screws rather than the general purpose exterior screws? Longer or shorter screws?

Over the subfloor, I plan on putting 3/4" T&G plywood. I understand that I should NOT screw this into the joists, but rather into the "field" of the underlying plywood subfloor (and NO glue over top of the subfloor). Do I screw this in using the same pattern as that used for ceramic tile floors, i.e., every 4" along the edges and every 6" within the field? Do I glue the tongue and groove joints? Do I allow 1/8" separation between the plywood pieces (including where the tongue and groove come together), in order to allow for expansion?

Finally, I'm going to go over the 3/4" T&G plywood with a floating vinyl sheet. Do I need to fill in the screw holes and where the sheets meet (which kinda kills leaving a gap for expansion)? Do I need to tape the plywood seams? If so, what kind of tape and what kind of adhesive?

Did I miss anything?!?

Your help is greatly appreciated!

Richard

 

[oh'mike]

You are over thinking this and missing a couple of things at the same time----

Lifting an edge and gluing what you can reach---no---you will pull nails through the board some where and end up with hollow spots when the stray nail won't let the board go back down.

Just screw it down well and get rid of the squeaks that way---

3/4" T&G ply is over kill and not the best for a finished floor---that is CD grade and will have open knots and some voids---to rough to put sheet goods over---

Best to use 1/2" BC grade---then add a layer of 1/4" sanded underlayment---installed with 1/4" small crown staples ---Multi Ply is one brand---
Avoid Luan Ply---that falls apart when it gets wet and sometimes will not allow your glue to bond due to the occasional board with to high a resin count----

 

[hammerlane]

Guess Mike totally changed your plans. But good to find out now than later.

Good info Mike.

 

[RichardZ]

Mike,

Thanks for your reply. As Hammerlane said, good to find out now rather than later.

I hadn't thought about the nails being a problem if I lifted the plywood. Thanks for the heads up -- I appreciate learning through your expertise/experience rather than finding out for myself the hard way! BTW, are the 1-5/8" general purpose exterior screws OK for my purposes, or should I use something else (e.g., deck screws? Longer screws? Shorter?).

Regarding the T&G, I'm a little confused. A flooring guy I talked with said to go with the 3/4" T&G, although at the time he may have thought that ceramic tile was going down. I got the T&G and was pretty careful about picking it out. There aren't any holes in the surface on either side. In fact, there aren't many knots either. I can take the T&G plywood back and get 1/2" BC, but I like the idea of 3/4" simply for strength. The dining room side of the kitchen entrance has a fiber soundproofing mat over which is laid parquet, the total thickness of which about 1". The parquet is then covered with carpet. Could I use 3/4" plywood (whether or not it's T&G) for strength, and go over that with Multiply?

Also, where do I get Multiply? I couldn't find it at Home Depot or Lowes. Do I need to go to a real lumber yard? A specialty place?

In looking at Home Depot's site, I saw many, many products for underlayment. One was called TriPly. Here's the link:

http://www.homedepot.com/h_d1/N-5yc...yword=underlayment&storeId=10051#BVRRWidgetID

Would this work?

I also saw rolls of 1/4" underlayment. Please don't hurt yourself laughing, but could I use any of these? I like the idea of providing additional soundproofing, probably easier installation, and maybe a softer feel under foot (although with a floated vinyl floor, this latter point might not be so good ...). Am I reaching for straws?

As always, I appreciate all your help.

Richard

 

[oh'mike]

If you have the 3/4" t&g ply---go ahead and use it----That is the standard builders grade sub floor and can be used with a good 1/4" underlayment----

The link you showed looked like Luan in the picture----I don't like Luan---It is used by many installers successfully---but I have seen failures so I won't touch it myself---

Look for a hardwood underlayment with hardwood----usually green Xs stamped on the face to show the proper stapling pattern---Menards sells it---most good flooring stores will stock it ,too.

 

[RichardZ]

oh'mike,

Sorry to take so long to get back to you.

OK, I'll use the T&G and put underlayment over that.

I've tried to find MultiPly. Unfortunately, Menards is only in the upper mid-west, and I'm in the Washington, D.C. area. I called the MultiPly company, and they said they'd get back to me, but unfortunately, despite my calling back, I haven't heard anything from them.

I'm wondering if I can use something else. Here's some 1/4" plywood options (all are 4'x8') from Home Depot:

o Moisture-Resistant Luan ($11 -- does "moisture-resistant" make it better?):

http://www.homedepot.com/h_d1/N-25e...&langId=-1&keyword=1/4"+plywood&storeId=10051

o SandePly Hardwood Plywood ($21):

http://www.homedepot.com/h_d1/N-5yc...d=1/4"+plywood&storeId=10051#customer_reviews

o Sanded BC Pine Plywood ($22):

http://www.homedepot.com/h_d1/N-5yc...&langId=-1&keyword=1/4"+plywood&storeId=10051

o Birch Plywood ($25 -- they go others besides birch, including oak and mahoganey):

http://www.homedepot.com/h_d1/N-5yc...&langId=-1&keyword=1/4"+plywood&storeId=10051

I also looked at underlayment at Lowes, but it was all rolls.

I can look at other sources (including several real few lumber yards in the area), but I'd need a bit more guidance on where to go ...

Lastly, could you give me any guidance on what type of screws to use, and how long they should be (1"?, 2", etc.)?

Thanks for your help,

Richard

 

[Seattle2k]

screw length...

Your first layer of ply is 5/8". The second layer is going to be 3/4". So, 5/8" + 6/8" = 11/8" = 1 3/8". So your screws should be at least 1 3/8" long. The 1 5/8" screws you have will be fine. Exterior or deck screws - whichever is cheaper.

Don't glue the tongue and groove, and there's no need to fill/tape the seams.

 

[RichardZ]

Seattle2k,

Thanks for the info. Can I also use the 1-5/8" screws to take care of the squeaks in the subfloor (i.e., to screw the subfloor to the joists)?

BTW, when I screw the T&G to the subfloor, do you have a recommended spacing between the screws (i.e., every 6")?

Lastly, if I may be so bold, any recommendations on 1/4" underlayment?!?

Thanks for your help!

Richard