old shower stall floor

[kalanikaau]

Circa 1959 home shower stall floor(36x40) in which the 4.25 square ceramic tile glazing is cracking/separating away from the tile base.
Its just the glazing material, not the actual tile itself. The edges of the glazing are sharp, defintely a hazard
My options so far are to either have the surface refinished or to lay another layer of tile over the existing surface, a total demo is out of the question.
The drain is located in a corner of the stall, I'm assuming it's 1 1/2" in diameter and that it is threaded into the cast iron trap below.
How would I go about raising the drain to allow for the added tile height? I am certain that there is a copper shower pan installed.
Access to the waste pipe is easily reached from the ceiling below this bathroom, I have no problem with converting part of the cast iron waste pipe to ABS.
In doing this will I compromise any existing seal, if any, between the drain and shower pan?
Again, a total demo is not possible

Hope someone can offer advice on this situation

 

[Jadnashua]

Well, a 50+ year old shower has given good service, and it might be time to rethink tearout and rebuild. But, depending on the drain you have, you MIGHT be able to raise it by screwing the top section up. Now, after all that time, this isn't a good certainty.

There is NO good, reliable way to replace the drain without tearing up the floor, as it would likely be near impossible to create a good seal to the liner. And, you may find that your copper pan is shot, especially if it gets distrubed.

You should know that, assuming it is a copper pan, 99/100 are installed wrong. The liner, by code, is the waterproof layer, and that MUST be sloped to the drain. The tile are considered decorative and a wear surface, not the waterproofing layer. It is almost certain that if you have a copper pan, it is installed flat on the floor. It may not leak, but it will NOT drain any moisture that gets below the tile level. This can lead to a smelly mess, constantly moist grout lines, and promotes growing mold and mildew. The only way to overcome that is a properly built one.

Another source of tiling help (lots of tiling pros there) is www.johnbridge.com.

 

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[kalanikaau]

Thanks Jim for your informative response.

I'd totally forgotten about the drain being attached (sweated?) to the shower pan, removing the existing drain will break that seal, creating a whole new can of worms.
The shower is intact, with no water leakage at all, nor any water buildup problems. Conferring with the original builder of the home confirmed a copper shower pan was installed, evidently it was installed correctly
I've already posted on johnbridge.com and am anxiously awaiting a response

Thanks again bud...