Q. While I was removing the old tile from a concrete shower pan in a slab foundation, a portion of the 1x5-inch raised physical lip separated from the slab below. It appears that the lip was formed and placed on top of the slab, and there is aught tying the two together (run across analogy, below). How should I repair this? Should I remove the complete lip and repour the whole thing, or repair only that section? How tin can I bond the new concrete to the old? Too, while making the repairs, should I hot-mop the pan?

A. Michael Byrne responds: Information technology may be possible to repair the existing curb, but y'all volition become better results past pouring a new reinforced adjourn that is bonded to the one-time physical with a concrete bonding amanuensis. Yous volition take to ensure that there is no wax, oil, grease, or soap scum on the face up of the physical slab that could ruin or reduce the bond. After that, I recommend that you lot install a sloped shower pan to incorporate the shower water and prevent harmful organisms from becoming resident in the surrounding walls and flooring.

As for hot-mopping the pan: In many areas, local building codes yet allow unprotected physical to be used as a base of operations for a ceramic tile shower stall, fifty-fifty though the practice is not germ-free, is not approved by the UBC, and is not sanctioned by the tile manufacture. I haven't recommended hot-mopped shower pans since 1974, when wellness and safety concerns convinced me to switch to Chloraloy 240, a CPE pan liner (made by the Noble Visitor, www.noblecompany.com). You could also check to run across if your local edifice department approves of using a surface-applied membrane system. The Schlter Company (www.schluter.com) makes a depression-profile drain and membrane organization that might work for you lot.