filling voids before laying down backer board?

[Rookie]

1/4 is fine. Schluter Ditra (which is one of the best) is 5/16. My whole house is 1/4 on the floors and 1/2 on the walls.

 

[Dirtebiker]

There are several products you can use. The main consideration as mentioned above is deflection. How thick is the existing subfloor?
as Rookie said, Ditra is a great product (VERY pricey!). Menards has the same product called Prova Flex. It’s 1/8” thick and helps with waterproofing and makes up for SLIGHT deflection. It’s expensive but you can put it down in a bed of thinset over the Luan (use the proper trowel and mix the thinset thin or it won’t stick), then thinset, tile, and grout. The “Power Grout” at Menards is good stuff for a bathroom.
For the gap between the Luan and the tub, use floor leveler or thinset.

 

[Rookie]

I wanted to use the Ditra, but cost made me choose Hardi-backer. I did the thin set and used a roofing nailer. The key is to make sure whatever fasteners you use don't go all the way through the wood or you lose fastening strength.

 

[printcraft]

I wanted to use the Ditra, but cost made me choose Hardi-backer. I did the thin set and used a roofing nailer. The key is to make sure whatever fasteners you use don't go all the way through the wood or you lose fastening strength.

I always use screws.

 

[Rookie]

Screws are better, but when you're doing over 1,200 square feet you try to find a shortcut.

 

[GodFearinGunTotin]

Screws are better, but when you're doing over 1,200 square feet you try to find a shortcut.

Stand up screw gun.

 

[Rookie]

Now you suggest it five years later!

 

[GodFearinGunTotin]

Now you suggest it five years later!

I know right? One of those inventions I wish I'd have thought of.

 

[Cameramonkey]

Phase one down.

Tile came up in 30 minutes. Cake.

I finally got all the Luan up and taller bits sanded, and staples hammered flush. THAT part took almost 4 hours.

So here I sit, beer in one hand, TENS controller in the other, waiting for the fam to go to bed so I can lay down the underlayment primer so that it can dry overnight.

The worst part? My handy dandy weighted floor scraper was useless for most of the floor. The abundance of [STRIKE]screws[/STRIKE] staples stopped it cold except for one pass. I want to kick that staple happy MOFO in the nuts right now. But the scraper attachment to my Rockwell multitool was awesome for the last thin layer of luan that stayed stuck to the subfloor.

 

[GodFearinGunTotin]

Phase one down.

Tile came up in 30 minutes. Cake.

I finally got all the Luan up and taller bits sanded, and staples hammered flush. THAT part took almost 4 hours.

So here I sit, beer in one hand, TENS controller in the other, waiting for the fam to go to bed so I can lay down the underlayment primer so that it can dry overnight.

The worst part? My handy dandy weighted floor scraper was useless for most of the floor. The abundance of screws stopped it cold except for one pass. I want to kick that staple happy MOFO in the nuts right now. But the scraper attachment to my Rockwell multitool was awesome for the last thin layer of luan that stayed stuck to the subfloor.

Ain't home improvement fun?

 

[Cameramonkey]

One other question. I called the inlaws to verify what to get to fasten the tiles to the backer. She suggested grout, but mentioned on one of their projects (they are our home improvement mentors) that they just used thinset. I should have plenty of thinset since the room is so small and I had to buy a 50# bag. Does thinset work well for adhering tiles to backer board? Or just OK so we should use mortar?

Given our last fiasco that caused us to have to redo this, I want to make sure Im doing this the best way possible so I dont have to do it yet again. I dont want any "it should be OK" solutions.

 

[GodFearinGunTotin]

What does your backer manufacturer recommend? As I stated earlier, I've just always used cement backer board with thin-set between the subfloor and the backer and thin-set between the backer and the tile. I'm of the understanding grout is for filling the joints between the tiles. Not sure of the mechanical capability differences.

 

[Rookie]

Yes, use thinset. Make sure it's for whatever type of tile you're using. Also, take the time to clean out the spaces between the tiles before the thinset dries.

 

[Cameramonkey]

Sorry, been a long day. She said MORTAR, not grout. So it’s between thin set and mortar.

 

[Rookie]

Thinset is mortar, just a thinner application.

 

[Cameramonkey]

Well, after a minor fiasco of raining mortar in my laundry room, my backer board is down.

I didnt realize how many voids I had in my subfloor due to a patch that was done to replace some rotting subfloor. I poured on the thinset and filled the voids, and they immediately drained out. Went downstairs and it was dripping all over my laundry room. *sigh*. I was going to fill the voids with latex caulk, but figured that flexing would be too much. It wasnt until I was watching it drain that I thought "I probably should have mixed up some regular mortar to tip into those cracks." Oh well. Too late now!

Oh well, its down, well screwed and now I'm waiting for it to dry so I can cut the hole for the toilet.

Thanks again INGO. You rock!

 

[Dirtebiker]

You don’t have a ceiling in the laundry room?
sounds like you chose the hard way huh?

 

[Cameramonkey]

You don’t have a ceiling in the laundry room?
sounds like you chose the hard way huh?

The unfinished laundry room under the bath is a true blessing. None of these events in the past several months involved sagging drywall and other nasty, mold attracting events. (this started with a cracked and leaking fiberglass tub)

And as a bonus I got to explain to my 11YO the benefits of self reliance and learning trade skills. He helped me pour in a little more thinset to float a small section that I missed in the closet. I pointed out that we have saved thousands on this project because we didnt have to pay somebody to come in and do this for us. And most importantly that leaves lots of money for things like toys, vacations, eating out, etc. I literally saw the light come on when I said that. Normally he is very "Come ON dad! Teaching me stuff AGAIN!?!?!? GEEEZ!" One of these days he will wake up and start to soak it in like I did with my dad. I hope.