Underlayment

[gsmittle]

Why not just use transition molding between rooms?

I can't speak for anyone else, but to me transition molding looks tacky.

My floor is finished, no squeaks and only a few quiet creaks where the subfloor creaked already. Someday I'll get around to fixing that, but right now it doesn't bother me.

g.

[Helicon1]

I would go with BOTH glue and screws. If you do it, I say do it right and make sure it's solid. I added 1/4" ply to an old 3/4" plank subfloor, and tiled over that. The subfloor obviously wasn't solid enough, and the grout lines cracked and a tile split. Do both and don't worry about it not being stable enough.

Thanks that was what I was going to do. Glue and screws. It is going under hardwood though and not tile, so that is a different story altogether. I had the tile installer use ditra which gives the uncoupling to prevent cracking under the tile.

Why not just use transition molding between rooms?

I could but we don't like them. Replacing all the finish flooring in the house, so why not have an entirely level surface.

As it turns out the tile is even higher than I even expected. So now I can safely go with 3/8 ply glued and screwed down under the hardwood.

My worries were with the 1/4 ply that the screws would pull through if countersunk too deeply and make noise, and alternately if using staples I was worried those would squeak over time as they would be going into 3/4 OSB subfloor. Not as much of a concern now with 3/8.

And I'm not worried about glue since adding the 3/8 everywhere in the house makes the subfloor an even 1-1/8" on all surfaces. If somebody wants to replace down the road, they don't need to go any further than the 3/8 ply.

[chopnhack]

Why not just use transition molding between rooms?

[woodturner]

BUT, when laying down something like ceramic or stone tiles you are faced with the problem of the subfloor flexing or moving under both the weight of the furniture, possible movement as the seasons change, and of course traffic. The tile itself will not flex and therefore if the subfloor is not absolutely stable, you will get fracturing at both the grouted seams and even cracking of the tile itself.

Not a tile expert, but I read the John Bridge forum ;-)

Most people on that board recommend Ditra or thicker plywood - the key is to limit deflection or flex, as you noted. They have a calculator on that site that will help determine if the floor is stiff enough for tile and can support the weight of the tile.

[cwsmith]

But "tile" is significantly different than a hardwood installation, as you have found out.

I really don't like glue for the pre-stated reasons (earlier post on this thread).

I guess staples, in conjunction with longer flooring nails would be sufficient. I do think that much of your installation would be the condition of the subfloor as it presently exists. For example, if it was 3/4 or better plywood already, then I think the addition of 1/4-inch underlayment really is only necessary to raise that floor to the kitchen level (as mentioned). My opinion is that unless the existing plywood is not in good, smooth condition the addition of underlayment does little.

However, if you are faced with old-style 3/4-inch boards (as in my 1887 house), then 1/4-inch underlayment would only slightly smooth out the possible uneven surface presented by any variation in thickness or cupping of the old boards. A thicker underlayment would be better.

BUT, when laying down something like ceramic or stone tiles you are faced with the problem of the subfloor flexing or moving under both the weight of the furniture, possible movement as the seasons change, and of course traffic. The tile itself will not flex and therefore if the subfloor is not absolutely stable, you will get fracturing at both the grouted seams and even cracking of the tile itself.

At my last residence, I remodeled the attached garage, changing it to a family room. The new floor consisted of 1 x 10 joists properly shimmed and leveled against the existing concrete floor and cross membered. I used 3/4 T&G good quality plywood which was screwed to those joists.

We had that area carpeted and we've had no problems whatsoever. BUT, when I thought about tiling the entry way, the installer would not do it... as in his experience that floor wasn't stable enough and he felt that the ply itself needed to be at least an inch thick, and better if possible.

That is my experience anyway,

CWS

[BigguyZ]

I would go with BOTH glue and screws. If you do it, I say do it right and make sure it's solid. I added 1/4" ply to an old 3/4" plank subfloor, and tiled over that. The subfloor obviously wasn't solid enough, and the grout lines cracked and a tile split. Do both and don't worry about it not being stable enough.

[Helicon1]

I'm considering doing the same thing. Adding 1/4 ply on top of 5/8 osb to raise the height of the floor to meet a new tile install in the kitchen rather than use transition strips. Finish floor will be 3/4 hardwood.

I think I am going to screw it down though. I'm not concerned about the staples pulling out, I'm concerned about them squeaking over time. I just pulled hundreds of them out of the new kitchen subfloor to prep it for new 3/8 ply and they didn't seem to be that secure.

Thoughts? Again it will just be to raise the height, not for strength. If the tile came out 3/4 high I would just lay the hardwood on the OSB.

[gsmittle]

I would be reluctant to use staples, they could pull out. One inch coarse thread screws set just below the surface with clutched setting would be ideal, IMO.

.

I'm not too worried about the staples pulling out, since there's 3/4" oak on top of it secured with a bajillion 2" flooring nails. If the staples pull out, I have bigger problems to worry about, like not having a floor at all. Gotta love living in tornado country!

g.

[cabinetman]

Staples was the right way to go, IMNSHO. 1/4" thick material isn't ideal for screws, have to screw-around too much with whether you get them sunk far enough, or too far.

I would be reluctant to use staples, they could pull out. One inch coarse thread screws set just below the surface with clutched setting would be ideal, IMO.

.

[All Thumbs]

Staples was the right way to go, IMNSHO. 1/4" thick material isn't ideal for screws, have to screw-around too much with whether you get them sunk far enough, or too far.

[gsmittle]

Flooring in Progress…

I ended up stapling down the 1/4" ply (no adhesive), then roofing felt over that (had a roll left over from another project, so it was cheaper than rosin paper). The flooring itself is 3/4" solid oak tongue and groove, nailed down with 2" flooring nails.

No living space under the room, just storage.

So far it looks pretty good, but still a long way to go.

Thanks to all for the suggestions/advice.

g.

[pelligrini]

Is there a living space under that room? If so, I would consider using a sound mat or one of the cork underlayment products. Although, shooting nails or staples through a sound product does decrease the benefits you can get on your STC and IIC ratings.

[os1kne]

I agree with this and some of the others. You don't want to use adhesive unless you absolutely have to.

+1. Screws are the best way IMO.

[JSUPreston]

I would screw down the ¼" if the floor under the ¼" is wood.

I agree with this and some of the others. You don't want to use adhesive unless you absolutely have to.

[cwsmith]

I've seen nails, staples, and screws all used on different floors. Personally, the only way I'd go would be screws. Not quit as fast as staples, but it's pretty quick none-the-less.

I'm not a big fan of adhesives for jobs like this. To me, that says that you're never intending to ever change the floor again.. or have anybody else do it either. Adhesives just present a mess for someone in the future to have to contend with.

The red-rozen paper under your hardwood will keep most squeakes away. That is what our flooring expert used throughout the house.

When I bought this old 1887-built home about seven years ago, one of the previous owners used adhesives to apply the sub-floor and also to stick the red oak wainscote to the kitchen walls. It was a nightmare and took days longer than it would have otherwise.

I hope this helps,

CWS