patching black mortar?

[vv2806]

Hi,

Some of the plaster around the window is cracked and unstable, so I knocked it off. There are 3 areas about 40 x 40 cm each.

It is a cavity wall, brick masonry from the inside, rendered with black mortar and finished with some sort of plaster.

What material shall I use to patch it? Cement and sand mix? In places it is down to the bricks, about an inch deep, in others just the top plaster fell off.
The whole room will be skimmed at the end.

Thanks in advance and have a nice long weekend!

 

[trowelmonkey1]

don't see why you couldn't use hardwall to fill them out.

wet the brixks down first then stick the hardwall in and rule it off, devil scratch it as it firms up ready for skimming.

 

[vv2806]

Thanks! Can I do it in one go (about an inch thick) or is it better to build it up?

 

[trowelmonkey1]

well, 'best practice' would say 2 coats but depending on suction you could get away with it, may suffer from slumping though when ruling off, generally only a problem on large areas though and as you only have 400mm patches i'd say you'll be fine

 

[vv2806]

Thank you very much, first coat is already done, will finish it tomorrow. Best regards! Val

 

[roughcaster]

well, 'best practice' would say 2 coats but depending on suction you could get away with it, may suffer from slumping though when ruling off, generally only a problem on large areas though and as you only have 400mm patches i'd say you'll be fine

I'd agree with that TM.