Window / wall tidy up.

PierremontQuaker03

Hi, I had my old wooden windows changed a few years ago to UPVC, and I am about to decorate one the bedrooms which has just been sitting empty. On closer inspection the sides of the wall next to the windows are a bit of a mess, they are uneven and bumpy. Do you think I will be able to sand this down to get it even. It looks like it could be cement, as I imagine when the window fitter pulled out the old wooden window it might have left a hole. Just googling this it looks like I would need a powertool to sand the cement, Any thoughts would be much appreciated. Sorry Pics added

FreeBear

If it is cement, it is going to be tough and resist sanding blocks. A power tool (angle grinder) will kick up a lot of fine dust.. You might want to try a carbide block first - https://www.screwfix.com/p/marshalltown-20-grit-rub-brick-152-x-76mm/600jf (cheaper suppliers available). Failing that, a scutch chisel will get the worst of it off and allow for replastering.

I suspect you have some old lime plaster on the wall. It may be that the cement is just sitting on the surface, and a few good taps with a hammer will get the worst of it off.

Bendy_House

As FB says.

Personally, I wouldn't even try and smooth the actual mortar, as I doubt it'll work to any usable degree, and it'll require a skim of filler regardless.

That wall looks as tho' it has lining paper on it? In which case blending in a filled patch might be awkward anyway, as the paper might light or 'fluff' around the edges when you come to sand it down - see how you get on.

I'd use a chisel - either 'cold' or an old wood type - and remove any high spots on that mortar, checking it with a straight-edge over it to make sure it's a bit below surrounding wall finish. Use a craft knife to tidy up the lining paper surrounding it so you have a neat edge that isn't lifting. Slightly dampen the mortar, and spread on a thin layer of all-purpose filler. Let it dry/set, and sand it smooth using 120 grit.

See what it's like, and add a further skim if needed. Repeat.

The cracks going down the corner in the first photo again looks like lining paper? So similarly, run a craft knife down each side, say, 10mm or so away from each side of the corner (to include all the loose paper), and sloping the blade away from the corner so's it cuts the paper at a slight bevel. Remove the ragged strip of paper over the corner. If there's a crack also in the wall itself, it may be worth squishing some PVA in there to try and bind it, but wipe away (with a damp cloth) any left on the surrounding paper surface. Once dry, use decorator's caulk to make the corner good. This could be tricky to do, and i'm not sure if there's a rubber bladed tool that could help - the kind used for siliconeing, for example?

FreeBear

Bendy_House said: I'd use a chisel - either 'cold' or an old wood type

You sir, are an animal.

Use the right tool for the job. And for this one, a wood chisel is definitely the wrong tool.

Bendy_House

twopenny

Lol I consider myself told off too. I use my grandfather's wood chisel for all sorts as its good at the job.
To the op I've used filler once I've established that the cracks are all it requires. A young man advised me to wipe the filler with a damp sponge gently then with a damp paint brush go over to get it blended with the wall/ceiling. If it needs it you can always repeat the process once the first is dry.

stuart45

Your grandfather's chisel is probably a really high quality steel, so it's probably really versatile, but better kept for it's day job.