I bought a 20's era house with original tile surrounding the tub enclosure. Now having to repair the old plumbing, a portion of the bed behind the tiles has broken down. It is the screen and mortar ( I think) construction that directly surrounds the tub spout. The tiles are good for re-use, but I am unsure how to repair the wall. I have access from the opposite side of the wall. I need to make this repair before the plumber can come back to finish the shower head installation. Can you help? Or does my question belong in another category?

How big is the hole ?

Roughly between 3 and 4 inches - it is between the tub spout and one of the spigot handles. We were planning to change over to a one handle style, does that help or hinder?
Thanks for responding so quickly!
Jackie

Is that tile still attached over the missing mortar or you can actually see through ?

You can actually see through. The wire mesh is misshapen, and we have the tile to replace when we have a good base for it.

Mix up small amount mortar and apply it over the lath. Don't build it up too much otherwise tile will stick out. Let it dry. Then put thin set on back of the tile and set it it place. Let it dry. Grout. Let it dry. Seal.

If the wire mesh is really a problem (I have had to do this on occassion), then cut off what is out of shape and replace with a new flat mesh (can get it at big box store). If you have bent or broken mesh - it's not going to be very effective to try to fix, so get rid of the area's that are - were you can.

Then use your concrete mix. Build it up - it will be messy. No vinyl concrete mix at all. Use a portland cement based concrete.

You may have to take off some tiles on the shower side first surrounding the hole. You probably have tiles from that hole that are cut anyway.

Then, as Milo suggests, make sure the concrete is flat with the other concrete on the shower side. Thinset to apply the tiles and set - modified thin set.

Because this is a repair, you have to understand this will be a weak point for moisture. Concrete does not adhere well to other conrete joints. Use a little slurry of thinset on those cold joints before adding your new concrete to help create a bond.

Is time consuming and messy, so once you start - be prepared. Wear rubber gloves - the concrete is really rough on your skin.

Hard to believe, but we are still fighting with this! We ran into some problems with the shower plumbing. The plumber didn't come back to finish the job when we got it all opened up for him - so we had to tackle it. We're using that copper bond epoxy - how does it hold up? Any pointers? We think we've got it together and no leaks, but I'd sure like some feedback before we get ready to close the wall back in (it backs up to the kitchen sink) and put the sink and all back together. The tile work went very well - with your help from this site! We still have the grouting to do on the shower side, but it looks pretty darn good for diy-ers! I should have asked how to cut that inch thick concrete wall backer! We ended up having to chisel it away - was there an easier answer? Masonry bits broke, and so on.
Thanks again!
Jackie