Installing Hearth for solid fuel

[edickon]

Hi there all,

Any advice would be greatly appreciated. I'm on the point of order a new slate hearth to go in our fireplace on the ground floor, and we're going to put a solid fuel stove in on top. Ideally what we'd do is get a slab of slate about 20mm thick (fine for building regs) and put it on the base but overlapping the floorboards a little so that the edge is clean. Can anyone advise me what's best to put between the slate and the subhearth (along with any installation tips). Also do I need to put any mastic etc between the hearth and the floorboards?

I've uploaded some photos on my profile. I reckon the difference between the height of the subhearth and the floorboards is around 3mm.

Many thanks,

Dickon

Untitled

• edickon
• 30 Nov 2009
• 1

Untitled

• edickon
• 30 Nov 2009
• 1

Untitled

• edickon
• 30 Nov 2009
• 1

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[Richard C]

Any advice would be greatly appreciated. I'm on the point of order a new slate hearth to go in our fireplace on the ground floor, and we're going to put a solid fuel stove in on top. Ideally what we'd do is get a slab of slate about 20mm thick (fine for building regs) and put it on the base but overlapping the floorboards a little so that the edge is clean.

The decorative hearth must be suitable for use with solid fuel stoves, if it’s in one piece it will probably crack from the heat; are you sure the constructional hearth meets BR’s? Difficult to tell from a photo but that certainly doesn’t look like it does to me. You must not over lap the floorboards with the hearth unless both it & the constructional hearth underneath projects more than 300mm front & 150mm to the side & it meets the regulations for size/depth; there is also a minimum distance from the fire with regards combustible material.
http://www.stovesonline.co.uk/stove-hearth-size.html

Can anyone advise me what's best to put between the slate and the subhearth

A sand/cement/lime mortar mix will do it.

Also do I need to put any mastic etc between the hearth and the floorboards?

See above. Is the flue currently lined & with what sort of liner? Do you have a permanently open vent in the room?

Be aware that such work is notifyable unless you use a registered HETAS installer & I would advise a little more research before you commit yourself. Here is just one of many websites Google will bring up where you can find a more user friendly version of all the Building Regulations you will be required to meet;
http://www.stovesonline.co.uk/stove_help_and_advice.html

For the sake of you & your family’s safety, please do it properly.

 

[edickon]

I've checked the BRs and the hearth is fine. We're going for a slim one so the distances both to the front of the hearth and subhearth are ok. Also the stove only kicks out 4-5kW so we don't need anything very thick.

We're getting a HETAS registered installer but from what you're saying maybe it would be better to get them to do the hearth as well. I'll ask them how much extra they would charge...

 

[Richard C]

I've checked the BRs and the hearth is fine. We're going for a slim one so the distances both to the front of the hearth and subhearth are ok.

That skirting (assuming it’s wood) won’t comply & the hearth (constructional & superimposed) must project a minimum of 150mm to the side & 300mm to the front. The other thing to watch is the surround; I don’t know what sort of fire was in there before or what you propose but if that’s ordinary Gypsum plaster on the wall next to the opening, it will only stand a temperature of 49 degrees C. Anything much higher & it will crack up & blow off the render base & if it’s a Gypsum plaster base, that will probably fall off as well. The temperature in the wall above my multi-fuel stove gets up to around 75 degrees C.

Also the stove only kicks out 4-5kW so we don't need anything very thick.

The maximum heat output rating does not ultimately dictate how hot the hearth & surrounding wall will get &, as I know, the Building Regs. do not differentiate below 5kW & such a stove will still generate high temperatures in the hearth(s) & surrounding walls.

Below 5kW you don’t need a permanent vent though.

We're getting a HETAS registered installer but from what you're saying maybe it would be better to get them to do the hearth as well. I'll ask them how much extra they would charge...

Nothing to stop you doing your own Building work, I did all mine; many installers will accomodate you as long as you discuss it with them before you start & they are happy that what you’re doing complies with relevant BR’s; they have, after all, got to sign off a certificate of compliance which says it does! Best option is to get a list of independent installers in your area from the HETAS website & get at least a couple of them round to discuss what you want & quote. A stove store will rarely or very reluctantly discount from the manufacturer’s list price which can save you a packet & can easily charge you double the installation cost you may get from an independent installer.