Cracking plaster on chimney breast above wood burner

D

Deleted member 32554

Guest
Hello I have re plastered my chimney breast several times due to cracking as I have a wood burner. Any ideas.
Assume burner has enough clearance , have you got a liner installed or just a pipe to register plate , was it professionally installed
What are you plastering it with , could you dab a pink sheet across the breast and skim
@Tinytom
 

Tinytom

Well-Known Member
Best method iv found is fermacel power panels dabbed on, skim the 2 sides and bed some render mesh into first coat, leave the back board bare. If we’re talking about the face of the chimney then you need to find out the manufacturers recommended distance to combustible materials.
pink plasterboard it’s normal is classed as combustible because of the paper lining
 

carys

Well-Known Member
Hello I have re plastered my chimney breast several times due to cracking as I have a wood burner. Any ideas.
Chimney breast shouldent crack. I'd understand if round the fire would. Carlite bonding good whith heat. Other options board it whith whatever sutible to heat.
 

brimplas1

Well-Known Member
I would never use carlite bonding on a brick chimney just because of salts and minerals.... Never mind it could cause damp issues....
 

smarts

Active Member
If you've got a log burner u shouldnt use anything gypsum as its combustible and will crack I always apply cement board and tape and fill any beads and joints
 

Brimstone

Well-Known Member
bof is on the money with the questions - it's cracking because it is getting too hot, before you get to finishes, why is it getting so hot - un-lined chimney? shot brickwork?, overburning/too big stove? Who put it in? etc.
And where is it cracking - way up on the wall or just above the stove?

As a guess; you've installed it yourself, not put a liner in, its an old halfbrick wall with uneven thickness, and you're running it way too hot. The brickwork itself is expanding and cracking in the heat, not just the plaster.
I like CrispyUK's solution!
 

smarts

Active Member
I cement board the whole front of the fire place tape and fill then plasterboard and skim the sides of the chimney breast
 

smarts

Active Member
Ocr is good aswell but is a slightly rougher finish than skim so I find cement board and fill beads and tape give the same smooth finish if painted
 

Ftp321

Well-Known Member
It's just one Vitcas bored smooth side out no need to skim as it will paint up exactly the same and just tape and feather in edges
 

Dollar

Well-Known Member
Sounds like his problem is the wall above fire

Forget any gypsum products the heat these kick out will just crack crumble j





Your welcome
 

worthwords

Active Member
I lime rendered our breast. Filled in the recessed mortar joints with horse haired lime then followed the spec from Mike Wye support team.
1583919309743.png


I was advised not to use any beading around the aperture - metal will expand and crack the plaster and plastic will melt. So I made a temporary frame pinned with dutch pins.

It was originally a 1930s but someone had gone mad in the 70s and added more bricks with a massive brick hearth which I have replaced with slate.

5Kw stove - installed by diligent HETAS guy who suggested some modifications. Definitely worth running past a pro first as there are specific rules around distance between stove and combustibles.

Not a quick job (took me weeks with 10 days curing for the thicker coats).


IMG_3176.JPG

IMG_2768.jpeg
 

Brimstone

Well-Known Member
Nice job, proper old school including the temporary frame. Guess you'll put the air grille on the other (right) way up when you decorate!
If you paint the inside the chamber, use the cheapest emulsion i.e. with the least amount of plastic additives.
 

worthwords

Active Member
Nice job, proper old school including the temporary frame. Guess you'll put the air grille on the other (right) way up when you decorate!
If you paint the inside the chamber, use the cheapest emulsion i.e. with the least amount of plastic additives.
Thanks.

Air grill as of yesterday.
IMG_3178.JPG

Originally there was an open fire so the when cavity wall insulation brutes came they made a mess of a combustion vent - unsleved, non compliant hit and miss and installed it upside down (2009).
The stupid thing is the draft coming from the vent was unbearable so negated any potential benefits from cavity wall insulation.

The room is big enough to not need a combustion vent so stove guy gave go ahead to brick it up. Luckily found a load of imperial bricks under the floorboards!
 

hollybank

Private Member
I lime rendered our breast. Filled in the recessed mortar joints with horse haired lime then followed the spec from Mike Wye support team.
View attachment 45696

I was advised not to use any beading around the aperture - metal will expand and crack the plaster and plastic will melt. So I made a temporary frame pinned with dutch pins.

It was originally a 1930s but someone had gone mad in the 70s and added more bricks with a massive brick hearth which I have replaced with slate.

5Kw stove - installed by diligent HETAS guy who suggested some modifications. Definitely worth running past a pro first as there are specific rules around distance between stove and combustibles.

Not a quick job (took me weeks with 10 days curing for the thicker coats).


View attachment 45693
View attachment 45694
The trouble with putting wood burning stoves in an aperture that size is all the heat from the stove heats the brickwork up and you see no benefit from it.
 

worthwords

Active Member
The trouble with putting wood burning stoves in an aperture that size is all the heat from the stove heats the brickwork up and you see no benefit from it.

Yes, it was a concern but in practice the stove is awesome and makes the room very cosy.Certainly a lot better than the old open fire in which the heat was sucked out of the chimney.
I put a 20mm vermiculite back to it so that most of the heat goes into the bricks or the room and thermal mass of the brick helps keep the room warm for some hours after the fire has gone out.

One of the benefits for replacing the brick hearth with a shorter slate was to improve circulation and I was able to squeeze this stove fan in the back

Unknown.jpeg
 

John j

Mono Don
I was gonna put a burner in but havi g a little en put me off. Also having to clean it and a woodyard in garden didnt appeal to me. Got one of them you put water in and it looks all fancy
 
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