Need advice on best way to redo drain for walk in shower

[mcu]

Nice little assistant. I got me four of those

How high and wide do you make your curbs? I will be using cinder blocks to make a bench and wondering if I could use some of the thinner center blocks or cut them with my wet saw. For the subfloor, the 2nd layer of plywood is only screwed onto the 1st and not the joists right? i will silicon my plywood joists and lay the CBU tomorrow morning. with versabond thinset and roofing nails on my mainfloor and in the master bath later this week.

For the plumbing any diagrams on how the best way you would go about settign up the ABS for the drain?

[jadnashua]

Concrete pavers can work well for a curb.

the idea of the second layer of ply is partly to decouple, partly to strengthen, and as a result, it should be installed offset from the first layer with no joints aligning and not into the joists.

The reason for thinset underneath the cbu is to fill in any imperfections to provide 100% support, not to hold it down, the fasteners do that. Most, not all, specify unmodified, but a modified will work as an alternative. Some specify a modified...basically, download and read the manufacturer's installation instructions.

A sample of two: HardieBacker and Wonderboard do not say anything about filling seams with caulk. Wonderboard does specify filling the gaps with mortar prior to installing the tape. At least on the backer, the idea is to make it a monolithic layer, the mortar and the tape help tie the individual sheets together. While filling any gaps in the ply with caulk can't hurt, none of those I've looked at specify it. If they felt it was that important, not wanting their product to fail, I think they'd specify it. Can't hurt. From what they told me in class, was that over time, the subfloor moving will cause the backer to crush around the fasteners into a powder to allow for some movement between the tile/backer and the ply underneath.

[mcu]

Thanks Jim. so the concrete pavers on plywood? should I glue it with PL glue since it's wood or still thinset instead?

the new subfloor i am building with 2nd layer of ply and cbu will still be 1/8-3/16" lower than the existign tile. I will then tile completely over the new floor and old tile to make one seemless hallway. to make up for the 1/8" would you guys just use a much thicker layer of thinset under the cbu to bring flush or use a type of self leveling over the cbu?

[jadnashua]

Level after installing the cbu. It's very unreliable to try to use thinset underneath it to perform this task and, you may have trouble getting the fasteners seated without squeezing out the excess anyway, defeating the purpose. While you can flatten after the cbu is down, for 1/8", I'd not try to do it with slc...I think you'd have a bigger mess. There are some products you can use, but most people would just do it with thinset while they were setting the tile. This takes a little more skill, though. At 1/8", you could just spread/screed out a layer of thinset, let it cure, then tile as normal. Thinset sticks to thinse fine.

I'd feel better using concrete blocks installed on properly bedded cbu than directly on ply.

[mcu]

Thant makes sense Jim. I will try to level after. Would you use a self leveling cement is a bit more than 1/8?

Also the backerboard manufacturer recommends either roofing nails or screws. Any beneit to using screws? I was not able to locate HD nails or screws at the local hardware shop. All are electro-plated

[johnfrwhipple]

I make my curbs very low to the ground. I shoot for 2" above the drain and once tiled the curbs look really slick. Building a curb out of 2"x4" 's, or a Noble Curb or Kerdi Curb nets these massive curbs with sometime heights over 6 1/2". I have to remove these types of curbs in the past.

If you where to suffer a hip injury or knee injury you could possibly not get into your shower.

JW

[johnfrwhipple]

Thant makes sense Jim. I will try to level after. Would you use a self leveling cement is a bit more than 1/8?

Also the backerboard manufacturer recommends either roofing nails or screws. Any beneit to using screws? I was not able to locate HD nails or screws at the local hardware shop. All are electro-plated

What type of drill do you own? I find many DIYers have pretty basic gear. Setting the concrete board down with a hammer and roofing nails will set it good. Set the board. Walk on it. Shimmy it into position and then bang in the roofing nails.

You want to lay the board slowly so you work out any trapped air. Work from one end and nail it off.

Never work from the outsides and work in to the middle.

JW

[mcu]

i have every drill you can think of I am not a beginner just not a pro, every day plumber or tiler.

Would you be able to send me a small diagram of how you would redo the ABS? We have a toilet, bidet and shower all on the same line next to each other. The other idea I had yesterday was getting rid of the bidet and getting those bidet toilet seats and possibly making the shower wider by about 16". Those toilet seats range from 300 to 1200 which is a big expense but do they break down a lot also?

[johnfrwhipple]

i have every drill you can think of I am not a beginner just not a pro, every day plumber or tiler.

Would you be able to send me a small diagram of how you would redo the ABS? We have a toilet, bidet and shower all on the same line next to each other. The other idea I had yesterday was getting rid of the bidet and getting those bidet toilet seats and possibly making the shower wider by about 16". Those toilet seats range from 300 to 1200 which is a big expense but do they break down a lot also?

I could send you a diagram of how I would do it but I'm not a ticketed plumber. There are too many variables and slight code requirements. When it comes to proper drain line and vent sizing - a seasoned plumber is the one you need. After all these years building bathrooms I'm still learning new points - I work with over 20-30 plumbers in a given year and learn a little bit from each one.

Why not post how you think you should do it and ask the plumbers here on Terry's site check your plan over.

JW