Fitting a granite or honed slate hearth
Fitting a granite or honed slate hearth
5 mins

Fitting a granite or honed slate hearth

Fitting a hearth for a wood burner: granite and honed slate for that smooth look

Granite and honed-slate hearths are perfectly smooth and polished with softened edges. An approximate price for a small to medium-sized hearth is £250 to £400 unfitted. They are reasonable straightforward to fit but are heavy. Shops often offer a fitting service.

Visit a specialist store to find out more about the different materials (there are places that specialise in worktops and hearths).

What do I need?

Sand, cement, PVA.

Building Control permission?

No. But the dimensions of the hearth will be inspected by Building Control (or your stove installer) when they inspect the stove installation.

Measuring

If the stove is to go into a recess it is usual for a granite or honed slate hearth to be in two pieces: the back hearth and the front hearth with a small expansion gap between the two.

When I measure the back hearth I usually make sure it will easily fit in (with approx. 5mm gap at sides and rear). Any gap can always be filled (or if you are lining inside the recess, after fitting the hearth, then the side and rear boards will cover the gap).

If stove is not in a recess then just choose your size and order it. See our article on hearth regulations.

I always order granite and slate hearths with NO base or upstands – just flat like a counter worktop.

Fitting

PVA the underside of both pieces and PVA the surface of the floor. Note that there should be NO combustible materials on top of your constructional hearth if you are in a fireplace recess so if a laminate floor impedes into this area cut it back (you can overlap the front and side edges of the front piece of granite/slate hearth onto the laminate (I tend to overlap 1-2cm). Carpet should be rolled completely out of the way at this stage.

I suggest you download Doc J of the Building Regulations at this stage and check the hearth section. Also see our article on hearth regulations.

Image: Granite with gap underneath filled with black mortar (add black concrete dye to mortar mix)

Make a sand cement mix (4:1 or similar). It should be wet to medium consistency rather than firm: you want the hearth to end up “hovering” approx. 5mm off the floor, too firm you will not be able to press the hearth down enough onto your mortar to acheive this, too wet and it will compress too much leaving no gap.

Image: Granite left to “hover” approx. 5mm (looks good). Useful for tucking carpet under.

Hearth install order of events

It is up to you whether you put the rear hearth down first or the front hearth first. If the floor of the recess is very flat then I would fit the rear first. If the floor is very uneven (sloping or excavated in the recess a little) then the front first. It is the front that is critical (no good fitting the back only to find out that this means the front ends up half an inch off the floor). The problem here is that if you mess up the fitting of the rear peice when you drop it in then it is very difficult to get out again (e.g. if you push it down too much on the mortar and it drops a few mm compared to where it meets the front hearth). I have got this wrong and had to then take the front one up again. The mortar will not have set but it is just frustrating and a little messy.

Put plenty of cow-pat type blobs of mortar on the floor of the recess – about 2-3″ gaps between them at most. Gently lower the hearth onto the blobs. With a spirit level on top of the hearth press it down a little bit at a time untilmit is hovering 5mm of the floor. You may need to press on the hearth and move it around a bit to get the mortar to compress. If your mortar is a little firm you can stand on the hearth. If you cannot get it down enough then you have to choose to leave it a little high or take it up and start again with a wetter mix.

Allow to set overnight. Voila!

FAQs

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Costs correct as of April 2023:

Approx. costs if you have a chimney and fireplace ready to use: £750-£1,000 (save £500 by self-installing).

Approx. costs if you have a chimney but need the fireplace "opening up": £1,600-£2,200 (save £1200 by self-installing).

Approx. costs if you do not have a chimney and need a clip-together flue: Shed £475-£700. Bungalow £1500. 2-storey house £2500. Save £1,000-£1400 by self-installing.

Above figures include labour and materials but no appliance.

We, of course, advise you to purchase your stove and materials from Stovefitter's to ensure quality goods are installed (some installers use budget materials to increase margin). If you buy your stove from us (rather than your local small shop or installer) we have a lot more power when approaching manufacturer's with a warranty issue. Why is that? Because we buy many hundreds of stoves a year from these brands.

We do not fit stoves.

But we know a few who do!

Google: Hetas installers

Hetas are the trade body of registered UK installers.

Most installations will require that you slide a chimney liner down your chimney (flexible metal tube 5" or 6" in diameter). Do you have a narrow chimney and want to lessen the risk that a liner might not go down your chimney? Then make sure your chosen stove can use a 5" liner.

Must I line my chimney? Best read this article but most likely the answer is yes. Do I have to fit a chimney liner?

DEFRA-Exempt wood burning stoves with a 5″ collar can usually be fitted to a five inch liner rather than the usual 6″ minimum, making the installer's job much less stressful.

ALL OF THE 5KW STOVES WE SELL CAN BE FITTED TO A 5" CHIMNEY LINER.

I seriously suggest any self installer fits a 5" liner unless they know their chimney is large enough for a 6"!

What is the best chimney liner? Silvacore 904 (we sell it so of course we will say that ;-). What is the best chimney liner?

Will your stove require an air vent within the room (some stone walls are very difficult to drill)?

5kW or under and wood burning stoves often do not require an air vent (new builds always require an air vent).

What is the maximum output in kW of your "5kW" wood burning stove? The majority of manufacturers just specify the “nominal output” and this figure means very little in real life. The nominal is a figure the manufacturer chooses to sell the stove at - the stove is capable of reaching at least this output with one fuel load. Nominal means "capable of". But it is not the maximum.

Check out the size of the area where the logs will go (firebox size) as this varies enormously. The kW output is completely dependant on the amount of logs burning at any one time - more logs burning equals more heat. If you can fit three logs in stove A and just two logs in stove B then stove A will be capable of throwing out 33% more heat.

DO NOT TRUST MANUFACTURERS’ kW RATINGS as manufacturers specify what output they desire to sell the stove at and testing allows for much “playing with the figures”. This is why you can get very small 5kW stoves (e.g. Aga Little Wenlock) and very large 5kW stoves (e.g. DG Ivar 5 by Dik Geurts which is actually rated 5kW but has a MUCH larger firebox than the Ekol Crystal 5 by Ekol Stoves). A Crystal 5k might get to 5kW and not be capable of any higher whilst a DG Ivar, despite being rated at 5kW, can get to 8kW with a full fuel load.

Note that, over time, one might damage the internal firebricks of a stove by running at a higher load than the manufacturer's suggest. Firebricks are easily replaceable.

Will your wood burning stove fit in your recess WITH the required air gaps around it? This is obviously not an issue if your stove will be freestanding.

Air gaps to non-combustible materials (brick, stone etc.) are usually "as close as you like" legally but manufacturers will sometimes specify a recommendation. This recommendation is there to allow heat to escape from the recess into the room - so you get the heat benefit rather than the heat soaking into the building structure and being lost. If no gap to non-combustibles recommended then we suggest 50-100mm air gap left and right of stove, 50mm behind and 100mm above.

Are you in a Smoke Control Area (usually built up areas)?

Choose your stove accordingly.

A stove must be DEFRA-Approved if you wish to burn wood in a smoke control area.

ALL OF THE STOVES WE SELL ARE DEFRA APPROVED FOR SMOKE CONTROL AREAS.

In simple terms if a stove has an efficiency rating of 70% then 30% of the heat from your logs goes up the chimney.

If a stove has an efficiency rating of 90% then only 10% goes up the chimney.

So think of this in terms of how many logs you have to chop/buy.

Example: A Saltfire Peanut 5 by Saltfire Stoves in Dorset has an efficiciency of 80%.

A tall chimney (6m or more) that is lined will be happy with an efficient stove.

Efficiency importance can be said to be overrated and anything between 75% and 85% is fine. Go much higher and performance can actually suffer (smoke in room when opening door to reload, blackening of glass).

Many modern stoves can go on 12mm thick hearths. Others require full, 5″ thick constructional hearths. All of the stoves we sell state whether or not a 12mm hearth is suitable.More about hearths for wood stoves here.

Can you can talk to somebody on the phone should you need to after the wood burning stove has been delivered, especially if you are self installing? Will the staff at “wesellzillionsofstoves.com” be able to assist with any installation issues? What if there are any problems after install?

Do yourself a favour before ordering stoves or materials on the Internet: Go to Trustpilot and type in the company name before you buy. Some companies advertising at the top of search engines are not good news - check for yourself.

When striving to find thebest 5kW wood burning stovesyou will likely be bewildered by the choice. There are many to choose from. The question I get asked most in our shop is “why should I pay <£1,000> for this one when this other one is just <£500>?”. Here is the very simple answer:the cheaper wood stoves are made in Chinaor Eastern Europe whilst the more expensive are made in Western Europe (or sometimes the USA). Here are a few examples where a more expensive stove might excel over a cheaper stove:

  • Aesthetics (more time spent on design)
  • Hinges (sometimes hidden on more expensive stoves)
  • Better quality glass
  • Thicker steel (longer life)
  • Improved door locking mechanisms
  • Longer warranty
  • Improved controllabilty of flame due to more resource invested on design of air flow within stove
  • Brushed steel fittings instead of cheapy chrome look

Open and close the door on a cheap Chinese stove. Then open and close the door on a DG stoveArada stovesWoodford stovesHamlet stoves or Saltfire stoves. You’ll understand the difference.

Stove pricing reminds me of wine pricing. A £20 bottle of wine is not double the quality of a £10 bottle of wine (the drinking experience might be improved by 20% as an example). We are talking “the law of diminishing returns here. They are all “fire in a metal box” at the end of the day.

Yes. However, there are specific regulations and restrictions in place to address air pollution concerns, particularly in areas designated as Smoke Control Areas. In these areas, only approved "smokeless" fuels or exempt appliances, such as Defra-approved wood-burning stoves, can be used. These stoves are designed to burn wood more efficiently and produce fewer emissions.

All the stoves we sell are DEFRA approved and Eco-design approved and suitable for all areas of the UK.

Terminology

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A stainless steel tube, slides down a brick/stone chimney to provide a smooth and safe route for smoke.

All of our stoves are approved by DEFRA to burn wood in all UK locations including Smoke Control Areas (towns and cities). Not all stoves are, so be careful if buying elsewhere.

All of our stoves are ECODESIGN approved to be sold in the UK. Not all stoves are, so be careful if buying elsewhere. ECODESIGN is mandatory by law since January 2022.

The base your stove sits on.

If the chimney is the polo mint then the flue is the hole.