Happy Labor Day

[Brad]

We have added 700 pounds or so over 175 sq ft.
I mentioned the issues to a guy who does framing for a living and he instantly mentioned crowns not all up. He said he sees people try to do that all the time and it leads to floors with hills and valleys like we have.

 

[Ian]

If that's ceramic tile I'm afraid it's going to crack to pieces. I did 18" tile in the kitchen/dining room over two layers of 3/4" plywood criss-crossed, screwed down to 2x12s on 16" centers with bird blocks every 4', then put 3x5x1/2" hardibacker down with thinset, staggered all joints, used appropriate screws, taped and floated the joints with thinset and HD alkaline-proof hardibacker tape, let it cure a week, then put the tile down with thinset. It has broken in two places across the room, right through the middle of the tiles. My problems might be due to a) following directions for the hardibacker and tile by setting the hardibacker in thinset to the plywood instead of doing what seemed logical to me and just laying it on tarpaper with half the amount of screws so the plywood could thermal/moisture cycle without forcing the hardibacker to move with it and B) the exposure to bare earth underneath, and proximity to a moisture seepage layer in the ground a few feet below. Hopefully in a climate-controlled house you won't have those issues.

 

[Brad]

The tar paper would work as a decoupling membrane. I'm using a product called Ditra for just that purpose. Keep the tile from moving when the sub floor moves and vice versa.
Using a product from the same company to waterproof the shower and tub surround. No water damaged walls for me.

 

[Ian]

That's exactly what's needed, something to "decouple" the masonry/ceramic from the wood, yet still allow firm support of the backer. Stupid me, I even went to a tile class and was told not to bypass the important step of gluing the backer to the subfloor with thinset, and to put backer screws every 6" in all directions. I knew it wouldn't work, but for ONCE I listened to the "experts". Kinda like the experts who say you have to shoot Linotype alloy in your .38 Special and keep those Marlin 30-30 loads under 1600 fps. Obviously you've had the benefit of better experts for your project.

BTW, my hat's off to you for diving into a project that big, doing the tub/shower/floor all in the same go must be a monster job for just the two of you in your spare time.

 

[Brandon]

Brad, both ditra and kerdi are excellent products, since you are using them, I assume you have also gotten recommendations from the pros about the different thinsets that you will need to use.

Laticrete makes excellent thinset, as does Custom.

Stay away from Mapei, and especially from Tec!!!

When you are laying the ditra, get the thinset Very thin, and then go about five times thinner, you want it like water.

For the planks, look into getting a lippage eliminator system, yes, they seem a bit expensive, but will be well worth it in the long run.

Happy to help with any questions you may have, and good luck!

 

[smokeywolf]

Always fun to try to put two materials together that expand and contract at dissimilar rates when exposed to changes in thermal and moisture levels.

Brad, it sounds like your daughter should be supervising this job.

 

[Brad]

I'm planning to use the Raimondi system to eliminate lippage.

Will need to look for a local place that sells Laticrete thinset. I'm well aware I need unmodified for laying tile over Ditra or Kerdi.

My wife would tell you I research everything before I buy. While some say GIYF she says I live it.