why put wire mesh in mud shower pan?

keep it from cracking is my guess...
randy

Some DIY sources suggest embedding a wire mesh in the mortar bed shower pan.
What is the purpose??
Here is one example:

Peter,
I believe it's reinforcement to help keep the mortar bed from cracking. If it does crack, the wire holds everything together.
I built a large 6'x6' curbless shower. I could not find the recommended wire lath locally, so I used galvanized 1/4" hardware cloth. It worked fine.
The wire mesh goes over a layer of plastic. This partially protects the subfloor below from the moisture of the mud bed and may act as a bit of an isolation membrane. More importantly, it keeps the plywood subfloor from "sucking" the moisture out of the mud bed before it can set up properly.
I used a waterproofing membrane called "Schulter Kerdi" and their proprietary drain system. Unlike the vinyl liner method, this keeps the water out of the mud bed in the first place instead of trying to deal with water that seeps through the mud. It also means you only need to make a single mud bed instead of two. It's a great system, and I highly recommend it.
You can find a lot of examples and helpful advice on the John Bridge tiling forums at
Take care,
Anthony

It works like rebar in a concrete slab. Mortar has excellent compression strength but very little sheer or expansion strength. The mesh counteracts this. ------------------------------------------=o&>o---- Steve Manes, Brooklyn, USA