QUESTION

How to fix or Replace crack in terrazzo shower curb - I have a crackled lip of a terrazzo three wall 42" shower pan. Can this be repaired. If not what is the best substrate for redoing the walls example lathe and plaster versus DensSheild. The shower is 44 years old.

ANSWER

ANSWER - I am assuming when you say lip, you mean the curb of the shower receptor.  The first question is to try to understand why the terrazzo cracked. Simply repairing it is a band aid approach that treats the symptom and not the problem.  If it is determined that it is simply a shrinkage crack that has opened up to a wider crack over time, then you could patch it with an terrazzo epoxy patch method.  If it is structural damage condition then it would be necessary to intrusively evaluate it to determine how or if it can be repaired. You don't want water to be able to leak and migrate into the walls or other areas of the home.

The best substrate for replacing the shower if it becomes necessary is to hot mop the shower pan and use a scratch coat over metal lath and moisture barrier, and level and square the wall with a mortar leveling coat.  All transitions should be properly flashed and the substrate surfaces should be waterproofed.  You can also install Denshield or other types of backer board on the walls.  You do need to make sure the walls are furred out and adjusted so the finish surface of the backer board is plumb and square. Good luck.