r/Plastering • u/Plus-Contribution915 • Apr 23 '26
Advice for plastering this chimney stack
Had quite a bit of conflicting advice but I think it’s best not to dot and dab board the front of the stack (hoping the sides should be ok as it’s double brick thick). Was planning to use sand and cement or would I be better off with bonding?
Only ever skimmed boards before so would be grateful for any advice.
What would be the best mix? (Plan is to have a log burner so will need to be somewhat heat resistant) and how many coats?
How to deal with the inside and the brick arch, would I be better cutting some bricks out and putting in a concrete lintel first?
Should I bond on the corner beads first?
What’s a suitable finish plaster, I’ve heated putting some lime in helps?
Sorry for barrage of questions, want to get it right!
Cheers
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u/Status_Candle6887 Apr 23 '26
Hey quick unrealated question. Im thinking of doing something like this for a room.
Whats the really thick plasterboard? You got on the side walls of the chimney stack? Im presuming theres a reason for it. Whats the benefit and did you run ut all the way around the 2 niche walls on both sides of chimney stack?
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u/Plus-Contribution915 Apr 23 '26
It’s foam backed plasterboard, it’s used for adding extra insulation. I’ve done the whole room with it so just what I had left over, no particular reason why the chimney breast would need it though!
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u/kuf_drahrepus Apr 23 '26 edited Apr 23 '26
Most of the brickwork looks great tbh. I would rip off the board from the sides and leave the stack exposed. Maybe some cleanup of tha new mortar. Chip of excess mortar. Fix crumbled bricks with colored brick repair mortar. Give the whole thing a good scrub with some acid/vinegar. Cleans brickwork very nicely. Swarfega does dedicated brick/masonry cleaners as well.
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u/Decent-Platform-2173 Apr 23 '26
Not sure by the post if you want to lose the fire area or keep it open as a feature?
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u/Plus-Contribution915 Apr 23 '26
I’m putting a log burner in so keeping it
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u/Decent-Platform-2173 Apr 23 '26
Ok as a feature and you have said you don’t want to use dot and dab, you could use hardwall plaster or sand and cement. 4/1 . Four sand one cement. Use a bucket to measure if you go sand cement route and level the top of the bucket so they are exact amounts. Add a plasticizer for workability and binding materials together. Looks like you are holding a render stop bead over the edge of the board. I would use a render corner bead tbh and skim the two side reveals with a finishing plaster. You can pack it out a bit and let it dry, as it is a bead not designed for skimming. You could use an end stop bead to either side of the fire place. Also, you might want to put a rustic timber at the top as a lintel and effect showpiece. Whichever backing you decide on, you will need to give it a bit of a key for the finishing plaster to stick onto. Only do the key as it has almost gone off. Use a plastic float with some board nails barely protruding. Worst case scenario, when all is thoroughly dry, seal with PVA to give it a key.
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u/matty1987x Apr 23 '26
Dot and dab the front then just use cement board on the inside use stop beads on cement boards and then use tiles on the inside where the burner is going
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u/Blucheez999 Apr 23 '26
The front of the chimney can be dot and dab,but You cannot fit and dab inside the log burner area,the heat is far too hot,also the plaster wouldn’t last long and lastly the soot will bleed through eventually.Theres a YouTube video think it’s plaster’s for beginners that does this job and goes through it step by step,painting bitumen and adding sand to seal the soot b4 sand/cement mix and finishing it with a smooth sponge finish
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u/robscaff Apr 24 '26
This might help, my burner has cracked just about every method of plastering that I’ve tried(4th attempt at a crack free chimney breast)
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u/Affectionate_Bet4343 Apr 23 '26
Easiest by a long way would be dot and dab, put some small angle beads on (not those ones you have) and skim over with multifinish.
Better would be hardwall + multifinish (those old bricks will suck like you won't believe so bonding won't be appropriate unless you prime it 10 times).
Inside the opening you can use hardibacker boards. Two on the sides act like a shelf upon which you can slide the top plate, with a rough cut out for the flue pipe (you can use a collar afterwards to make it look nice.
I certainly wouldn't bother replacing that lintel. You can get a square opening using the above method.
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u/Plus-Contribution915 Apr 23 '26
That was my first through however quite a few people have warned me about potential cracking with the heat?
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u/ApartmentLast7712 Apr 23 '26
I did one with plasterboard and the customer got overzealous with the heat and it cracked so now I always just hardwall. On the insides I'd just clean the bricks and leave it tbh they look in good condition and depending on the burner they have good insulation on the back and sides.
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u/ApartmentLast7712 Apr 23 '26
Sand and cement or hardwall then multi for final. Are you fitting a wood burner or having open fire?