Hearth Size

Keith99

I'm currently looking at putting a hearth in that will eventually have a stove on it, which will be in a fireplace recesss.

I've been looking on http://www.stovesonline.co.uk/stove-hearth-size.html and I might be being stupid but I'm not 100% sure I'm reading it correctly.

"
Hearth thickness


If the hearth is on a combustible floor it must be at least 250mm thick or...
The hearth may be 125mm thick if there is a 50mm air gap underneath it or....
If a stove has been tested and shown to not raise the hearth temperature to over 100 degrees centigrade over ambient room temperature then a 12mm hearth may be used.

If the hearth is on a non-combustible floor (for example a concrete floor slab) then the total thickness of the hearth together with the non-combustible floor must be 250mm or...
125mm thick with a 50mm air gap underneath or....
Again if a stove does not raise the hearth temperature to over 100 degrees centigrade then a 12mm hearth may be used. "

However this website - http://www.stovefittersmanual.co.uk/articles/hearth-regulations/ states you need a constructional hearth although I think you don't need it if the hearth is over 250mm (as above).

Anyone agree or disagree with me?

minibbb

On taking up my hearth I found I had a constructional concrete hearth underneath (1930s house)
I fitted 20mm Indian sandstone slabs which were fine when we had our woodburner fitted. HETAS approved installed was happy with it - most hearths you see for sale online are 20mm too- some people even use glass!

I didn't know the thickness of the constructional hearth mind you but it was solid! Hearth gets hot but not too hot to touch under the stove.

MX5huggy

What’s the floor under the hearth made of?

Keith99

MX5huggy wrote: »

What’s the floor under the hearth made of?

The section outside of the recess is concrete but not the 300mm it requires and its a semi circle.

250mm deep is quite deep - I'm sure I am missing something!

Or does it depend on how hot the stove will send heat to no more than 100c (as below)

"A stove installation into a fireplace place recess

• A constructional hearth is needed (unless the stove is certified to not heat the hearth to more than 100ºC, in which case a 12mm hearth is sufficient).
• Minimum projection into the room of 500mm.
• Minimum of 150mm wider than the recess at the point it opens into the room.
• Minimum 250mm thick (or a minimum of 125mm thick if there is then a further 50mm air gap before any combustible materials)."

https://blog.gr8fires.co.uk/2015/09/15/building-a-hearth-for-a-wood-burning-stove/

System

what stove are you planning on fitting?

Ectophile

If you want the official word from the government, have a read of https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/468872/ADJ_LOCKED.pdf section 2.22 onwards.

The diagram in that document looks just like the one in your post.

Keith99

the_r_sole wrote: »

what stove are you planning on fitting?

I don't know yet - I will be getting one that fits in the reccess, with enough space around it and will heat the hearth to less than 100c

System

Keith99 wrote: »

I don't know yet - I will be getting one that fits in the reccess, with enough space around it and will heat the hearth to less than 100c

so you'll only need a superimposed one min 12mm thick?