What are my walls made of?

[Boot]

Im doing a little work in my bathroom and am to the point where I have to add some drywall or something to a couple places. I've noticed that my whole house has this stuff in the walls. I though they were plaster or something but after ripping into one it looks more like Mortar or something and it is on there THICK! While I lke the strong walls I've come to a speed bump in trying to come up with options for matching it.

House was built int he 50's
This picture is probably going to be huge, but it'll help to see it.
This is a section of drywall /whatever that the old shower overlapped a bit.


-Boot

 

[dbenke]

Should be a plaster and lathe wall, but around the shower/tub you will have a morter base at least
3/4"inch thick. It was used as a tile base.
Messy job. knock it all out, and put up hardie (concrete board) in its place.
I've done quite a few. Take a sledge hammer to it, but try not to crack the plaster on the other side

GOOD LUCK

 

[77cruiser]

DBenke hit the nail on the head. Watch out for the corners though. They are typically a very thick chicken wire mesh that cuts you if you look at it wrong and its not comfortable!
Chisel it out and then install hardi or the DUROCK board. You can feather it back in with Sheetrock mud though around the edges and you should be fine.

 

[Boot]

cool thanks guys.