Plaster opening in concrete wall

[trumanders]

I have made an opening in a wall with concrete block. Now I need to smooth the edges and then plaster it. The question is what type of plaster to use? There are cavities in the blocks, and it feels like it could take a lot. Should I plaster with something coarser that I can apply a thick layer of, and finish with something finer? Tips?

I thought I would place a board that sticks out a little on each side, fill the gap, and then use a board to get a nice edge.

 

[neo11]

Rendering mortar c, but don't really understand how you're supposed to plaster.
Is a TV supposed to go into the wall or what?

 

[Gregx81]

Plaster is very convenient for larger applications (up to 60mm) per layer, depending on the manufacturer. Also easy to work with.

 

[trumanders]

Gypsum plaster is very convenient for larger applications (up to 60mm) per shaft, depending on the manufacturer. Also easy to work with.

Ok! Is it good as it is or do I need something more on top? I've never used gypsum plaster, but it sounds like it's not as durable as mortar or render?

 

[trumanders]

Cement render, but I'm not quite sure how you're going to render it.
Is a TV going into the wall or what?

There will be an opening. There's wallpaper, paint, and a bit of render left on the other side. It's the edges of the opening that need rendering, where you see the ends of the concrete blocks. The blocks didn't break so neatly because I used a jackhammer.

 

[trumanders]

Putsbruk c, but I don't quite understand how you're going to plaster.
Is a TV supposed to be in the wall or what?

It seems like there are CS I, CS II, etc., many to choose from. Some say max 5mm per layer. Maybe it's good with plaster that CLBFS wrote about.

 

[Gregx81]

Ok! Is it fine as it is or do I need something more on the outside? I've never used plaster, but it sounds like it's not as durable as mortar or render?

It's possible to just use plaster, then filler or whatever you're going to have for the "finish".
Plaster becomes really robust when it has dried. No risk of cracks when it dries as can happen when you plaster either.