Katipo said:
But I don't know what the exposed wall is made off? I mean, it looks grey, could it be cement?
That'll be render I expect, which is a mix of sand and cement. In order to replaster, you'll need as a minimum these tools/aids:
bucket
plastering trowel
bit of wood to knock up
a big flat board on which to pour the plaster onto to work from
container (ideally another bucket) of water to keep tools clean as you go
But ideally, you'd want a hawk and a gauging trowel as well.
Assuming it's a normal sized wall, one 25kg bag of finish plaster will be more than enough. Will cost about a fiver or less depending on where you buy it.
You should first brush the wall down, making sure all loose bits come away, then seal the wall using PVA 1:5 water solution. Give it at least a couple of coats. You'll not need much PVA, so buy the most economical one you can find.
Fill the bucket about halfway with water, then add plaster, continually stirring, until you get the right consistency. Unfortunately, it's hard to relate what that is like this way. It should be viscous enough that it doesn't slop everywhere as you work with it, but not so much that you don't have enough time to work with it.
Once it's knocked up, pour a load onto your board, then using your plastering trowel you apply the first coat to the wall. Don't worry about it being neat, just make sure you get a fairly even spread across the whole wall. Wait a short while for it to go off a little, smooth it out a bit, then apply your second coat. Once that's done, you trowel off ie: smooth it out and get as perfect as possible a finish. Pay particular attention to the edges.
Once you've done that, immediately remove all snots from the ceiling/skirting/adjacent walls, and throughly clean your tools.
There's a cartload of stuff I should be telling you, but I'm probably going to forget a lot of it. With regards to the actual plastering, when trowelling off you'll have to discover the knack of making passing motions without digging into the plaster with the corners, or moving too slowly and letting the trowel get stuck, which means when you remove it you end up taking a chunk of plaster with you.
As you're trowelling off, make sure you keep using your water to keep your trowel clean. As it's your first time you'll be working too slow, and so as you trowel off you'll find the plaster hardening faster than you would like. In order to overcome this, sprinkle a bit of water onto the problem areas, ideally have an old paintbrush which you can use for this.
I could add a few more paragraphs but I'm afraid I'm out of time (got to get ready to go out), but even if I could mention everything I can think of, I strongly recommend you read a book on it, or even better if you know someone who can plaster, try to get them to come round and advise/teach you (don't just ask them to do it though - take advantage of their knowledge, and learn how to do it yourself so you can do it in the future.)
Good luck!
/Damn, just noticed it's only a small section of the wall...well what I said above still applies, and one bag will definitely be enough. Don't mix up as much as I said though, or you'll end up with far too much plaster for the job.
Personally, I'd do the whole wall though. Sounds like it could do with a new coat, but seeing as it will be your first time perhaps you should just deal with that area so it's easier for you.
