Plastering over Sand/Cement Mortar?

[FresnoBob]

Hi people,

After removing some stud walls, we have a couple of areas of bare block that the studs were fastened to.

There's about 15mm to make up in these areas. As I have plenty of sand/cement, I was debating whether it would be possible to make up most of this deficit with mortar, then skim a little plaster over the top (total plastering newbie here, and only used mortar for basic paving and bricklaying in the past).

Does this sound reasonable, or is it a big nooooo? lol

Thanks in advance

 

[kingandy2nd]

Yeah, you can do that. Plastering is a dark art though, so you need to prep properly and be confident in your skills to get a nice smooth surface.

How big is the area to be repaired?

 

[FresnoBob]

There's a strip around 10-15cm wide by about 3m high where the old stud was fastened direct to the blockwork, I might also have to chip away in the middle section slightly as the current plaster isn't of the same level on what was both sides of the old wall.

This section of the hallway isn't very big, so the plan was to try plastering on a few off cuts of plasterboard, then use the hallway itself as a test before moving onto bigger rooms.

I've actually got a tub of ready mixed Wickes Plaster Skim, which I'm lead to believe is slightly different to normal plaster and is possibly a bit more filler-esque. Gonna see how I get on with this, then progress to the proper stuff later on I think.

I'm always very thorough with the prep side of things, and usually get a good finish with most fillers I use, as I really don't mind a lot of wet or dry sanding afterwards. Hopefully I pick this up quickly lol.

 

[kingandy2nd]

Plastering is all about practice and timing so very good if you can practice as much as possible first.

Regarding the strip, use neat pva (and let it dry) on the brickwork to seal it before you apply the sand and cement to the gap. Once that's dry, pva the new surface and then use your wickes skim stuff.

As with any plastering, your main focus should be getting it one the wall first (don't worry about smoothing it to start with). Get it on the wall in total, then as it starts to go off apply a second coat. Once this is on the wall, then you go back and smooth repeatidly, wetting your trowl as necessary. That's the very basics... plenty of threads on here about how to plaster.

I'd get a bag of multi finish for the hallway job, just use the wickes stuff for the strip job.

Good luck