OK thanks for the info, The area to repair is kinda small. I just wasn't sure how to secure the lathe. And I have to see if theres even a block wall behind it, It may be wood. Does that make any difference. I do believe there is black waterproofing paper behind the lathe currently. Just leave that or remove and replace that too?
As you can see from the picture, the mortar coating must have been very thin because the rusted lathe is visible seeping out. And the part I accidentally broke open, there was no metal left, it all crumbled.
Or, is there maybe a better way to protect/cover that area instead?
