I’m interested in your Cornerstone insulating render, I have a query. My application is a 1930s red brick house, I wish to use it in the bathroom to insulate internally. I have the room stripped back to the brick. It is lime mortar and uninsulated cavity, I do not plan to insulate the cavity. I need to tile the bathroom, some walls full height (shower enclosure) and others half height.

I’m trying not to use modern materials but I’ve been told that if I tile onto the Cornerstone render that I may encounter issues with the adhesive failing to adhere or perhaps failing in the future due to moisture penetration.

Do you have any thoughts?

Is it a workable option to use Cornerstone render, maybe 40/50mm then apply shower tanking paste over it and then tile onto the tanking paste? I know this will mean the render becomes non-breathable into the room, but the cavity will not be insulated and moisture could breathe into the cavity?

The bathroom is on the first floor so no damp issues, unless I create them!

Thanks in advance.

andy_s_kerr Unselected an answer May 6, 2022