Chimney Breast Plastering for an inset fireplace

T

Throwgnilli

New Member
Hi,

I have a Chimney Breast with no liner on the flue and sealed with a cast iron inset fire.

It must have been intalled for 10 years and before I hacked off all the plaster and render I saw that it had cracked.

I can find alot of information about rendering the insides of a fireplace when a log burner is installed, but nothing on what to do on the breast around an inset fireplace.

Is there anything fancy I need to do? I am dotting and dabbing the rest of the room and unsure what to do around the breast.

If there is some sand and cement rendering to be done or vitcas, what's the best way to blend it in to the dot and dabbed sections?

cheers
 

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Throwgnilli said:
Hi,

I have a Chimney Breast with no liner on the flue and sealed with a cast iron inset fire.

It must have been intalled for 10 years and before I hacked off all the plaster and render I saw that it had cracked.

I can find alot of information about rendering the insides of a fireplace when a log burner is installed, but nothing on what to do on the breast around an inset fireplace.

Is there anything fancy I need to do? I am dotting and dabbing the rest of the room and unsure what to do around the breast.

If there is some sand and cement rendering to be done or vitcas, what's the best way to blend it in to the dot and dabbed sections?

cheers
Click to expand...
I would d&d it then use Universal for that. You should get away without vitcas due to the distance off heat source. Maybe some would disagree with that ?
 
The Hetas Chimney sweeps we use advised not to use plasterboard as it's a combustible material and that they wouldn't be able to sign it off.

I've been thinking about using a sand cement and lime mix 5:1:1 of NHL 2 or 3.5 on the front and cheeks.

That way I can use render bead on the external corners of the breast which would then return to the dot and dabbed walls.

I'm really not wanting to use vitcas as it seems so expensive and everyone on here moans about it, or gypsum as it seems it just cracks.

The only thing I don't get now is how to finish the sand cement and lime render.

Can you use a lime plaster over a sand cement and lime render? Or should it only be used with a lime render?
 
Throwgnilli said:
The Hetas Chimney sweeps we use advised not to use plasterboard as it's a combustible material and that they wouldn't be able to sign it off.

I've been thinking about using a sand cement and lime mix 5:1:1 of NHL 2 or 3.5 on the front and cheeks.

That way I can use render bead on the external corners of the breast which would then return to the dot and dabbed walls.

I'm really not wanting to use vitcas as it seems so expensive and everyone on here moans about it, or gypsum as it seems it just cracks.

The only thing I don't get now is how to finish the sand cement and lime render.

Can you use a lime plaster over a sand cement and lime render? Or should it only be used with a lime render?
Click to expand...
Plasterboard isn't a combustible material. Its used double sheeted on commercial ceilings for fire rating purposes.
 
I've read otherwise. And they're the ones signing it off.

However I'm really interested in help and advice on the above if possible.
 
Throwgnilli said:
The Hetas Chimney sweeps we use advised not to use plasterboard as it's a combustible material and that they wouldn't be able to sign it off.

I've been thinking about using a sand cement and lime mix 5:1:1 of NHL 2 or 3.5 on the front and cheeks.

That way I can use render bead on the external corners of the breast which would then return to the dot and dabbed walls.

I'm really not wanting to use vitcas as it seems so expensive and everyone on here moans about it, or gypsum as it seems it just cracks.

The only thing I don't get now is how to finish the sand cement and lime render.

Can you use a lime plaster over a sand cement and lime render? Or should it only be used with a lime render?
Click to expand...
Since when do you let a chimney sweep tell you your job?

Dab it.
 
Throwgnilli said:
I've read otherwise. And they're the ones signing it off.

However I'm really interested in help and advice on the above if possible.
Click to expand...
You read wrong.

How combustible is plasterboard?


Plasterboard has a low smoke density and low flame spread index, and it serves as a heat-insulating barrier. It is classified in the National Construction Code (NCC) as non-combustible and is critical in terms of meeting fire regulations under the NCC — such as critical radiant flux and group number requirements.
 
Spitandpolish said:
Plasterboard isn't a combustible material. Its used double sheeted on commercial ceilings for fire rating purposes.
Click to expand...
Stevieo said:
You read wrong.

How combustible is plasterboard?


Plasterboard has a low smoke density and low flame spread index, and it serves as a heat-insulating barrier. It is classified in the National Construction Code (NCC) as non-combustible and is critical in terms of meeting fire regulations under the NCC — such as critical radiant flux and group number requirements.
Click to expand...


Unfortunately from the fire makers specs, plasterboard is combustible

I can't set fire to it, but they say it's combustible


Probably good resistance if the house goes up, but constant and consistent naked flames (which is what they have to expect and cover for) it won't stand up.
 
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