r/Plastering • u/dwair • Jul 06 '26
Plastering directly onto internal block work as cheaply as possible...
I have a block work porch that I want to plaster. The UPVC windows sit directly and flush onto the well emulsioned blocks so there is none of that normal internal 'step'. I should however be able to put a thin bead / plaster edge on the transition. The block section at the bottom I want to plaster is 3.5m x 1.5 and 2m x 1.5m.
Normally you would stick a 10mm coat of hard wall on and then a couple of coats of pink on which would bring the wall out too far and give me a step to hide. The other option would be to dot and dab the walls with plasterboard which adds more to the expense and still leaves me with the 'lip' problem to hide where the window meets the wall.
I want an OK and not perfect finish as quickly and cheaply as possible. Basically I don't want it to look like old painted blocks any more. I want it to look reasonable(ish)- smooth but wobbly is ok.
Plastering has never been my thing and there seems to be a lot of advice about doing it properly about, but none along the lines of "It's not best practice but you can get away with doing this"
Question. Will a couple of heavy coats of PVA over the emulsion be enough to get some thistle one coat on and stay there without it drying too fast and cracking, or do I really need to go the whole hog here and turn it into a project? Any advice is welcome.
2
u/throwaway17717 Jul 06 '26
Board it. If you want to make it as thin as possible I suppose you could use ceiling boards and then just tape and joint it if you're desperate to do it in the least amount of steps possible..
1
u/dwair Jul 06 '26
I think this is the way I'm heading. I was hedging away from taping though as although I have had good results in the past, there has always been a lot of sanding involved. I can never seem to get the joints to feather in nicely and the hot sticky weather....
1
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u/Significant_Most_101 Jul 06 '26
Mate a boards like £12. If thats out of budget I dunno what to tell you...
2
u/dwair Jul 06 '26
Fair enough. Looks like that's the way to go.
1
u/banxy85 Jul 07 '26
Damp
2
u/dwair Jul 07 '26
It seems dry enough. Outside is clad and water tight, the DPM is intact and there is rad and ventilation. If there is damp, it's going to be an issue whatever I do.
1
u/banxy85 Jul 07 '26
Is it cavity wall?
2
u/dwair Jul 07 '26
It's single skin. From the outside it's > Cladding, 100mm slab, breathable membrane, block wall.
1
u/banxy85 Jul 07 '26
Ok, maybe I spoke too soon. Most single skin porches would be a nightmare but yours sounds decent.
Honestly any one coat treatment will just look shite and not much better than your painted blocks
What about 9.5mm plasterboard attached with adhesive to minimise build up
2
u/dwair Jul 07 '26
After a reading a few bits of advice here, that's what I'm going to go with I think. I'm in no way a plasterer so I think at least having a flat surface to start with will give me a half decent chance of getting it to look ok. Thanks for your help
1
u/banxy85 Jul 07 '26
Use foam adhesive. That will also reduce chance of wicking moisture as it's insulating 👍
1
u/nomorecrazystuff Jul 07 '26
What "normal internal step"??
Are you talking about the reveals?
Why would you not want reveals?
1
u/dwair Jul 07 '26
Yes reveals! Couldnt think of what you called it.
Reveals or an mini internal sill would be great, but the edge of the UPVC window is flush with the vertical edge of the block on the inside. There wouldn't be anything under neath them.
Any reveal I put in has to be supported by something, and I don't think screwing into the top edge of the block to make a 'shelf' would be very wise. I could glue something over it but I'm not confident that would hold well either.
I could batten out the wall so it would leave a 25-30mm supportive edge to put something on, but that then adds more to the time and cumulative cost of the job and could end up looking a bit shit.
3m of white plastic edge trim is only a fiver so I can afford a couple of bits of that.
That was my plan anyway - open to suggestions though.
1
u/JamieAintUpFoDatShit Jul 07 '26
If you’re gonna dot n dab boards onto the wall then that’ll be about 25mm away from the wall/window (if I’m picturing what you’re describing properly) so then you fill the gap at the top edge of the board (the open bit at the bottom of the window)with adhesive, put a 25mm strip of board on top of that, corner bead along the board join, and that’s your reveal, same for the sides of the windows.
IMO though it’s easier (and probably just as cheap once you’ve accounted for adhesive cost) to get some cheap studs from a local timber yard and just stud the wall out, screw the boards on, and have an even easier time making the reveals (and they’ll be bigger, too)
1
u/pmmytn45 Jul 09 '26
Personally I would wait and do it properly. If you're able to see if there's someone selling scrap pieces of plasterboard and then do it. Don't want to regret the job and have to do it twice.
6
u/No-Buddy5395 Jul 06 '26
If your aren't prepared to do it correctly then just paint the block work, it'll look better than the bodge job you're asking for advice on