render or plaster

[johnad]

I am about to re-plaster a chimney brest wall all the old render has been stripped back to the brickwork I want to install an oak mantle then finish the walls before putting in a log burner.
My question is should I render with sand and cement ?
Or should I use bonding plaster with a skim over ?
And can the oak beam be used as the lintel over the fire or should it be above the fire with brickwork under it i.e. what distance up from the fire should it be ?
I intend to finish the render/plaster across the chimney Brest and into the fire back.
Any information please.
Many thanks

 

[PrenticeBoyofDerry]

If log burner is going it the recess under chimney. I'd render the recess but above the fire on chimney breast personal choice.
As for mantle, what output will the log burner be and what do the manufacturers instruction allow.

 

[Richard C]

I am about to re-plaster a chimney brest wall all the old render has been stripped back to the brickwork I want to install an oak mantle then finish the walls before putting in a log burner. My question is should I render with sand and cement ?

Sand/cement/lime will withstand much higher temperatures without cracking, or use a specialist render mix;
http://shop.vitcas.com/vitcas-heat-resistant-plaster-16-p.asp
But I think the formulation is going to be very similar.

Or should I use bonding plaster with a skim over ?

Definitely NO, Gypsum based plaster will only withstand 50C degrees or so, much above that & it will fail; your wood burner will exceed that by a fairly large margin.

And can the oak beam be used as the lintel over the fire or should it be above the fire with brickwork under it i.e. what distance up from the fire should it be ?

BR’s require that “combustible material” must be at last 150mm from the stove but above the fire, this should be at least 300mm IMO where the temperature can easily exceed 75C degrees. Here’s a useful link, take some time to browse & absorb to info on there;
http://www.stovesonline.co.uk/wood_burning_stoves/Register-Plates.html

I intend to finish the render/plaster across the chimney Brest and into the fire back.

A suitable render is OK but don't use Gypsum based plaster for the above reasons; ensue you keep at least 300mm (500mm is better) clear above & 150mm to the side (300mm is better)

Just so you’re aware; the work you are doing is notifyable unless you use a HETAS registered installer. As a minimum you need to get the flue checked & that the constructional hearth & ventilation is checked for compliance with current Building Regs; over 5Kw will need a permanently open vent. You will also be asked to produce a certificate of compliance when you come to sell up!