Question from Jim Blog reader

I came across your responses to questions re: waterproofing and I appreciate your response as I am about to do a demo of a walk in shower. I will be taking it down to the studs as I am sure it has regular sheet rock and not hardieback as mold keeps coming through the grout. it is tiles floor, ceiling and walls.

My question is: I am removing all walls and tile and installing hardiebacker. I will be scraping tiles off the floor/pan and assume it is a poured concrete pad as the shower is a customer size - pretty long. After I scrape the tiles off the floor/pan and before I reinstall new tiles, will I have to do anything to that pan such as re-waterproof or perhaps even do a whole new pan? If I do, I will probably have to hire a professional as I am not confident that I can pour a new floor/pan. And I am afraid once I start demo, if I have to have a new pan installed, I will be waiting to find a professional to do it and that puts the shower out of commission for a long time. What are your thoughts and/or suggestions? Nothing has been started at this point.

RESPONSE

Jim

if you remove the tiles from the concrete pan carefully without cracking or gouging chunks of the concrete there is no reason you cant install new tile on it without removing it. If its a little rough or some thin set is left on the concrete you can just skim coat it smooth with thin set then let it dry a day  before you install new tile. There is no reason to remove the concrete and redo the pan if it is not leaking. Another options is to install your new tile on top of the existing tile floor just treat the existing tile with concrete bonding additive so the thin set will adhere good to the old tile lay your new  tile on top of the old tile . As for your drain  remove the drain grate screws and drain grate lay your tile so as the drain grate will sit flat on top of new tile(tile is laid just 1/4  inch inside of drain edge leaving screw holes clear to reinstall grate screws) get longer drain grate screws and screw grate flat on top of dry grouted finished tile.