Plastering onto Supalux board

X

Xinebessa

New Member
Good evening all

Can anyone assist with some advice please? I have a fireplace built out of metal frame with supalux board. My plasterer has had a go at plastering onto it (following the guidelines as its high suction) today and it appears like i have a huge number of hairline cracks. Its hard to see actual cracks for the most part so maybe its just how the plaster is drying (but knowing my luck this isnt the case).

I have attached some photos.

The whole thing was pva'd 24hours before the job and then pva'd again before the actual work.

The plasterer is good, has done a fine job on every other wall in the house so i suspect its due to the board (not him) but im wondering what my next steps should be.

Any thoughts? ;-)
Plastering onto Supalux board
 
It’s a 8x4 cement board iv used it before inside fire places, iv had the same thing it’s very very high suction.
you can risk and paint over the crazing you probably won’t be able to see it, or seen as it’s such a small area anyway get him to give it a weak pva first then a strong pva and reskim it won’t craze on the second skim
 
The spec , but best to consult technical Re the heat
 

Attachments

  • Plastering onto Supalux board
    015769C3-4932-42BB-AF64-2906157B0F59.jpeg
    231.7 KB · Views: 397
madmonk said:
Vitcas would go over that nice ive used loads yo will have to use there own pva though that comes with it
Click to expand...

Cool thanks, i did look at this but saw lots of people said it was tough to get a good finish. Its a flu fire with a good gap between flu and board (ive also double boarded around the fire so hoping ill be ok with normal plaster but of course time will tell. Maybe if i end up going for PVA and a 3rd coat of plaster i will look at using this
 
Tinytom said:
It’s a 8x4 cement board iv used it before inside fire places, iv had the same thing it’s very very high suction.
you can risk and paint over the crazing you probably won’t be able to see it, or seen as it’s such a small area anyway get him to give it a weak pva first then a strong pva and reskim it won’t craze on the second skim
Click to expand...

Thanks, how thing could the skim get away with being? Reason i ask is that its skimmed flush with the edge of the fire currently so i guess it was need feathering to this edge.

Cheers!
 
So looking at it today its dried futher and the "cracks" are like very fine white lines within the dark lines but dont actually seem to have much depth (e.g i cant feel them if i run my nail over them).

Guess it sounds like the plan will be to paint over them, see what happens and if they show through then wack on another coat.

Where do you guys land on latex paint? Does it cause any problems if i need to then plaster over it?
 
@Tinytom - was this using gypsum plaster, and has it taken the heat ?
- Failed instantly for me, as Madmonk I then had to use vitcas (which I think is a lime plaster finish?)
Superlux is expensive and a PIA, rather use Hardiebacker.

I don't see any way a latex paint will take heat, but can always learn otherwise - cheap emulsion every time for me.
 
Brimstone said:
@Tinytom - was this using gypsum plaster, and has it taken the heat ?
- Failed instantly for me, as Madmonk I then had to use vitcas (which I think is a lime plaster finish?)
Superlux is expensive and a PIA, rather use Hardiebacker.

I don't see any way a latex paint will take heat, but can always learn otherwise - cheap emulsion every time for me.
Click to expand...

When yours failed and you had to use vitcas did you take off the old plaster or vitcas over it? Also what type of fire was it? Mine is balanced flu with a good gap between flu and board. My main concern is the bezel around the fire where it meets the plaster.

Learning lots on this project i can tell you!
 
I didn't have to take it off, it blew off itself - expanded and popped out like big bubble as the stove was getting hot. This was wood stove, gas fires don't get so hot. Outside of a balanced flue even less.
Bezel? Do you mean the cover ring around the balanced flue where it goes thru the wall/closure?
Where the fire meets the plaster? Unless this is an inset stove they don't touch the plaster, so is this the front face into the room?
 
Brimstone said:
I didn't have to take it off, it blew off itself - expanded and popped out like big bubble as the stove was getting hot. This was wood stove, gas fires don't get so hot. Outside of a balanced flue even less.
Bezel? Do you mean the cover ring around the balanced flue where it goes thru the wall/closure?
Where the fire meets the plaster? Unless this is an inset stove they don't touch the plaster, so is this the front face into the room?
Click to expand...

Ah crikey! Sorry i mean the black frame around the glass of the fire (its a double sided fire). The flue had a good 15cm gap before the board that the plaster is on and there is also a sacrificial board between the plastered board and the flue :-)

Ill wack up a photo
 

Attachments

  • Plastering onto Supalux board
    1597742292647940158265204318946.jpg
    766.1 KB · Views: 244
Mmm, might get away with that as is. suck it and see I think. If it has convection grilles to move air thru' the false chimney breast even better.
 
Brimstone said:
Mmm, might get away with that as is. suck it and see I think. If it has convection grilles to move air thru' the false chimney breast even better.
Click to expand...

I will be putting some vents on either side of it, is this what you mean? I was told to install them low to allow air to be sucked in as heat rises
 
Brimstone said:
Yes low, and high, so that the warm air comes out into the room
Click to expand...

Thanks, there is also a hole above where the flue goes into the loft to let hot air escape to try and keep the temperature inside down a bit. Appreciate its a bit energy inefficient but this is a beast of a fire!
 
Quick update... slapped 2 coats of paint on it (starting with mist coat). Once dry the paint along the cracks ended up raised.. sanded with 240, painted again and its all good :-)
 
You must log in or register to reply here.

Share this page

Back
Top