I live in nyc and, although it's antiquated, I have to have my contractor build my tiled shower floor base using a lead pan. It is required per code in the city. I am discovering that my contractor isn't the most skilled in the tiling department and I don't necessarily trust his abilities making this perfectly watertight. All my internet searches for installing a lead pan only come up with stories of people removing one to put in a PVC pan. There is nothing out there describing the necessary steps to fasten the drain to the pan, building the preslope, getting the pan to lie on the preslope when it's such a tough material (unlike the pvc), etc. I just want to ensure he's taking the proper steps and not cutting corners that will cost me down the road. He knows that grout and tile and deck mud/mortar are not waterproof but insists that I won't have a problem with a flat lead pan, sloped mortar on top and tile on top of that. I feel unsure about that given all I've read about the pvc method and the idea of water seeping to the pan and not draining, leading to mold etc. Does anyone have experience putting in lead pans they can share? I appreciate the help.