What size screws for underlayment

[Kman]

If your joists are 16" on center, you can get by with 2x4's. I usually splurge and get 2x6's to give me something bigger to drive the screws into, but it's really just for convenience.

[Motordoctor]

Since I added the hallway now to the kitchen floor project, I have another question. Is there an issue using Ditra in the hallway and the CBU in the kitchen? Assuming roughly the same heights? Putting the Ditra down in that hallway would be much easier than trying to cut CBU to fit 5 doorways. The stack will be 3/4" ply subfloor with 1/2" underlayment with the Ditra on top. That should match up with the kitchen which has 3/4" planks, with 1/2" underlayment and 1/4" CBU. Sound reasonable? The length of the run from the kitchen down the hallway would be 20ft. Thanks.

[cx]

There is no reason not to change substrates, Dan. Can't comment on matching heights. Can't see it from here, eh?

[Motordoctor]

Excellent. That should make things a little easier. Now I just have to figure out how to get the subfloor in place. The kitchen was easy, this hallway is going to take some time to fit two layers of ply. I bought one of those oscillating tools to cut out the old subfloor under the door casings since I couldn't get a saw in there. It's a HF special for $29. The blades that came with it of course were junk so I had to buy some decent ones. The couple of cuts I got from the supplied blades was impressive until the teeth wore off Like a hot knife through butter. At least on the door jambs.

The tile layout will have about three tiles with 75% on CBU and 25% on the Ditra. Should I make that interface a "soft joint" so the Ditra side is free to move relative to the CBU? Work is kicking my behind right now, the shop is packed with motorcycles. Wanted to get this project done before it started but didn't happen. The wife was the joker in the deck having that wall removed. The next thing is going to be the bathroom floor. Since the hacks put the tile down on the plank subfloor, it's going to be about an inch lower than the hallway. It just keeps getting better

Tried uploading a picture but it won't let me. Might still be some issues on the server.

[Motordoctor]

When gluing and screwing the subfloor to the joists, would the preferred glue be PL400 Loctite or Titebond wood glue? Thanks.

[HomeDepotAssociate]

Earlier on you guys suggested dan use customblend thinset under CBU. When you're doing that, you skip the admix, correct? Just water and thin set?

Also, Dan, out of curiousity what tile did you guys get from HD?

[cx]

That would be correct, Chate'. Perhaps the only application for which we'd generally recommend the use of Custom Blend at all.

My opinion; worth price charged.

[Motordoctor]

The tile I'm using is this one
http://www.homedepot.com/p/TrafficMA...ULMK/204834499

The wife and I were walking through HD and saw it on display for cheap. The kitchen floor was terrible and since we want to sell this place in a year or so seemed like a good idea. The tile was about $130 for enough to do 140sq ft. Getting the floor ready for that cost about ten times that and I still haven't laid a single tile on the floor. Since I'm adding the hallway I need to get another three cases of it since the hallway is about 40 sq ft.
Reminds me of another saying on a different forum. The most expensive car you will ever own is a free or cheap Mercedes Benz. Have one of those parked in the driveway and they aren't kidding.

[Motordoctor]

Hey, is Masonite a good material for shimming some plywood on a low joist? I have it in 1/8", could cut it into strips and glue it down. It's a small area, about 2 ft in length on a 2x8 joist. Thanks

[HomeDepotAssociate]

that's funny, im sitting right across from that tile as I type this! Also, thank you CX. I will make sure to pass that along to customers in the future. As it stands, I don't recommend the custom blend for anything.

[cx]

Dan, I'm generally opposed to trying to shim joist tops for flattening or leveling of subflooring. Very difficult to eliminate unwanted gaps at the ends of the shims and potential fastening problems.

Masonite would not be my first choice of materials if I did wanna do that, but in an area where it would be perpetually dry it might work OK if properly set in place with good construction adhesive.

My opinion; worth price charged.

[Motordoctor]

Would it be better to sister the joist with a 2x4 to take up the low area instead of the shimming? I've been putting in a lot of blocking to make up for the subfloor ends. All this getting off the floor is killing me, I don't mind crawling around on the floor but the constant up and down is murder. You tile guys are studs!

[cx]

That would be my preferred repair/flattening/leveling method, Dan.

I never use anything smaller than 2x6 for that work, but that's mostly just a personal preference to get more contact area for glue and screws and make life easier.

[Motordoctor]

What is your preferred glue to use on that application? I'm assuming that deck screws would be the screw of choice?

[cx]

Current favorite is PL Premium from Loctite.