Suitable filler/plaster for concrete block wall

I am altering a new build (crest nicholson house) en suite into a wetroom. I have gutted the room: 2 walls are stud and the other 2 walls are concrete block. The walls will eventually receive marmox board or similar with tiled finish.

When I carefully removed the old 'dabbed' plasterboard invariably bits/chunks of the conc block wall came with it. Some areas are significant like the window jamb (see photo attached) and other areas are spoon size 15mm deep holes. Some areas are just the joints that require filling.

I want to make good the walls before applying the new structure.


Can someone tell me which filler I should use for a conc block wall in this situation? Can I invite a 2nd opinion.[/u]

That reveal blockwork is terrible, shocking!

There are straight nick perp's for at least three courses - below, at and above the lintel bearing. The lintel bearing block itself is mostly mortar!

Absolutely shocking. The so called bricklayers would need to have been ultra lazy when building this detail.

All the holes could be filled with mortar.

In fact, the more i look at the blockwork the more it puzzles. It almost looks as if the window reveal is a rectified mistake and that the window has been relocated.

Probably.....?

Noseall or anyone else who is watching...............when you say use mortar could you be more specific.

I just want to go to a DIY store and pick up a ready mixed bag of what?....What about bonding plaster or is that too granular for the smaller, shallower holes?

And yes Noseall, that did not cross my mind but you could well be right about the moving of the window opening, the general build of the house is poor and I can see looking at the exposed floor joists that changes were made. Fortunately, the lintel in the photo is below the wallplate (this wetroom is on 1st floor). I hope to make good use of this forum for this project.

Appreciate any replies

6 parts builders sand to 1 part cement will be your normal mix for mortar, you can make it bit stronger. Some plasticiser will help when laying it.