Kerdi Line Drain Remodel Questions

[SECBuilders]

Long time reader, first time poster -- help!

Starting a bathroom job today.

We'll be installing schlueter products, including their linear drain in an entrance to the shower location.

As a result, I need to raise the remaining bathroom floor area by 3/4" to match the height of the schlueter shower pan at the drain (7/8"). I'll use ditra over the raised floor to get the extra 1/8".

My question is... Does using a mortar bed to raise 3/4" over a 50 year old cured concrete slab with ditra on top of it sound like the way to go?

Would you use deck mud or??

Thanks!

[Hank B.]

yes, I'd bond the mud bed to the slab with thinset.

[SECBuilders]

Ok sounds good hank. I was worried the mud bed wouldn't be thick enough.

[jadnashua]

Schluter also makes a ramp that extends about 15" (don't quote me on that number) to ramp back down to the height of the floor before the shower slope. One thing that is suggested is to put a secondary drain in that area to potentially take care of any moisture that may get past it.

[Hank B.]

I'd probably just slow the whole floor outside the shower to the drain at the showers entrance, since apparently the height isn't an issue.

[SECBuilders]

Height isn't too much of a problem, I don't want to raise it any higher than I have to for transition purposes -- but I think I'll be good.

The floor is 12x24" large format porcelain tile, so sloping will be a challenge.

[jadnashua]

IF this will get wet, you also need to know about the WET COF. Large format tile have so few grout lines to increase traction, it can get very dangerous, especially if people might be running around in their bare feet. One recommendation presented to me was that you need a wet COF of 0.6 or higher for any safety.

[SECBuilders]

Jim, great point. I am installing a tile with high slip resistance.

Rough in is almost done, time to use John Bridge's dry pack formula and raise this floor. I'm planning to set some 3/4" conduit for screed reference.

[Tiling SB]

Sounds like you are on the right track , post some pictures of your progress.

Happy mudding

[SECBuilders]

I've got a shower stall that I need to bring in by 1/2" on either side.

The water proofing material will be Kerdi Board, so it seems like using 1/2" plywood might be the easiest way to go -- since sistering studs to bring it out by a 1/2" would be difficult considering all of the framing and blocking for Niches and such.

Anyone see an issue with using 1/2" plywood to bring the walls out? Since everything will be waterproofed over it, seems like the way to go.

I'd use 1" Kerdi Board, but I already have a few packs of 1/2", and it's expensive stuff to double layer.

[Screw Loose]

Why not use 1/2" drywall? It's cheaper $$$ than plywood, is less likely to warp and is easier to work with.

[cx]

If you want to fur out the walls with plywood, Nick, I'd recommend you rip two-inch strips for each stud and attach them with construction adhesive and mechanical fasteners.

You might do better scabbing on some additional studs if you also need to plumb or flatten the walls.

Is this the same bathroom that's getting the mud floor?

My opinion; worth price charged.

[SECBuilders]

CX,

You got it. I got delayed a week -- had to make some extra slab cuts with plumbing issues from whomever originally built the addition.

I thought of the same thing that you're saying -- rip a bunch of 1/2" CDX and laminate it to the studwork. Then I figured.... shoot, I've got a few extra sheets of 1/2" ply laying around in the shop from our last job, it might just be faster to rip it to size and throw it up as a unit.

The studs are pretty flat already after taking a look with a straight edge.

Typically, I'd fur out a wall by sistering studs -- but there's blocking with plumbing in place, and I'd rather get moving so I can get that floor floated, and put the trench drain in for the shower. These trench drains are beautiful, but man they require a lot of planning. That's the reason for the wall fur, this trench drain is going at the entrance of the shower, so I want to ensure that it spans the exact width of the finished tile walls to prevent any water from slipping past it.

[jadnashua]

It won't hurt anything to use full coverage ply underneath the Kerdiboard. Your time to rip it into strips, then attach is likely to be more than just using the full sheet material.

[Houston Remodeler]

I like the drywall idea. You can do a full spread of thinset and get a really strong, laminated substrate.