First time posting and I realy enjoy reading the forum.
I was called to be a project manager on a large custom house.
I was inspecting the shower pan with the plumber and the mud in the shower is less then an inch to the top of the underlayment of the curb. What is the minimum space between the mud in the shower pan to the top of the underlayment of the curb? The plumber tells me that the cement board over the curb underlayment and the saddle are enough to give the height to the curb.
For me something doesn't add up. My feeling is that once the 3/8" tiles with the thinset it will come up basically to the top of the curb underlayment. Any thoughts?
Thanks

There is no minimum height above the pan. The curb is only there to allow you to be able to construct a properly sloped shower pan (1/4" minimum to the foot rise from the top of the drain to the furthest vertical wall intersection) and allow an aesthetic separation to the adjacent bathroom floor.

As an example, in an ADA or roll in shower there is virtually no curb and it just has a slight hump at the entrance or a flat bathroom floor with a depression in the actual shower area.

I would be more concerned as to how the pan was constructed. Any idea as to the construction method used?
Does it have the following?
- proper size and type of drain (with weep holes)
- proper preslope and liner placement
- proper finished slope
- proper curb construction with no punctures in liner material

Did the plumber install the drain and pan liner? If so, you really need to verify the above points.

Some people don't want much of a curb. Typically I build the curb using 3 - 2x4's.

I wonder how thick the mud is?



I agree with that. I've never seen a pan installed by a plumber that was done right. The main fault, no pre-slope. 2nd problem, pan installed so that you could only do a mud job on the walls, cuz of the way it was folded. Too bulky.

Of course if you install board at and on the curb, you've destroyed the membrane and need to apply a surface waterproofing. Of course most don't and just cover it with tiles only to leak one day.

Jaz

the curb cement board you mentioned is the part that worries me. The pan liner is supposed to extend up and over the curb. There is no way to fasten cement board to the top of the curb without puncturing the liner. The curb needs to be mesh re-inforced mortar over top of the liner.

I just found out from our inspector that we as tile installers when we perform a tile in shower pan that we are subject to the rules of creating a fixture. We need to be 3" above the shower dam with our membrane and fill with water to the dam height, no hardie, dura rock, ect will penetrate the curb with fastners. We use 3 2x4 as the curb and in some cases use a 4x6 wood curb. like was said before hadicapped curb are almost non exitent, so curb height on the inside is what is is.