Multi Fuel Burner 21 February at 4:43PM in In my home (includes DIY) MoneySaving 25 replies 625 views

Primmie

Last August I had a multi fuel burner installed in a small fireplace opening which had been left by the previous owner (the stove is one of the smallest available).   On the day of installation the fitter had bought heat boards with him (as agreed in the original estimate) but advised me he didn't think they were necessary as it was a brick fireplace that had been plastered.   On his advice I agreed.   The company refunded me the cost of the heat boards.   Unfortunately as soon as I started using the wood burner cracks appeared on both sides and at the rear of the fireplace.   I have not used the fire since last December.

I contacted the company last December and after chasing them with emails and phone calls plus a site visit they advised me the only two solutions would be to make the fireplace opening taller and wider.   I have no understanding if this is possible but it doesn't seem a particularly viable option as the wall on both sides of the opening is only 9 inches wide.   This would also mean having the granite hearth replaced plus all the mess and extra costs involved.   They mentioned it might be possible to have heat boards installed but were unsure what they could do between the edge of the board and the outside wall.   They then mentioned they didn't think this was a good plan despite arranging for the boards initially.   I have been chasing them up and in desperation emailed to ask if they could install the heat boards to see if this would help.   Today I received an email with an estimate of £700 for the work to install the boards.   I was rather shocked at the price having already spent nearly 3,500k on having the fire and hearth installed.   

I am unsure what to do next or whether the figure quoted is deemed acceptable.  Many thanks for any advice in advance. 

Ganga

How much are the boards and how much of the £700 was labour?

Ectophile

There needs to be space all around the burner for the (very hot) air to circulate.  Mine has about 3" (8 cm) at the sides, which was about the minimum the installer could get away with.

If the plaster is cracking up, then the obvious solution is to remove it entirely.  There would then be more space to fit the boards.  Or not fit them at all and live with bare bricks (like mine).

stuart45

The chimney breast jambs should be at least 9 inches, so it's not really practical to widen the opening.

FreeBear

Primmie said: On the day of installation the fitter had bought heat boards with him (as agreed in the original estimate) but advised me he didn't think they were necessary as it was a brick fireplace that had been plastered.

Gypsum plaster ?

If so, no surprise it has cracked and it will end up flaking off. Stuff like Multifinish will only tolerate temperatures up to around 50°C. Any higher than that, and you need a heat resistant plaster such as Vitcas or a lime render.

I have a temperature sensor embedded in the wall above my stove and regularly see it getting above 120°C. Highest has been just shy of 180°C.

If you plan on painting the wall around the stove, be aware that it will get very hot, so pick your paint carefully - Lime wash may be worth considering.

Primmie

Thankyou all so much for the advice.   The company refunded me £225, which, on the original estimate, was the cost of the boards.    The recent estimate again lists the price of the Glassroc at £225, the frame, which I assume is just the edging, at £116.67 and the remainder for the installation.   Unfortunately to do any work the fire will need to be removed.   As advised the chimney piers are just over 9" wide and the space between the fire and the side of the fireplace is just under 5" and from the top of the fireplace to the stove just over 9".   Unfortunately I have no idea what type of plaster it is as it was there when I moved in and I am not good at DIY.   

ThisIsWeird

Primmie, could you post a piccie, please? And the make and model of the stove?

marycastle56

Plastering's a lot easier than the pros like to let on. Especially if it's a small area. I'm completely not a diy person also but with the help of youtube and google I managed to do some work that otherwise would have cost me £100s

FreeBear

marycastle56 said: Plastering's a lot easier than the pros like to let on. Especially if it's a small area.

As per my earlier post - Around a stove, gypsum plaster should not be used as it will not tolerate the heat. Either a heat resistant plaster or a lime render needs to be used. The Vitcas stuff is not easy to use, and lime requires extra time & effort. Lime is a bit more forgiving though.

For a small recess such as a fireplace, lining it with calcium silicate or cement board will be quicker and easier. Use a suitable adhesive, and it shouldn't need any further finishing beyond a coat of paint.

Primmie

Thankyou all for further advice.   The fire is a Stockton 3 Multifuel Stove. 

ThisIsWeird

Thanks. Very neat.
How certain are you that the surround is plastered brick? If it is, then apart from the aesthetics, I personally wouldn't worry - it's very unlikely to be damaged further.
If you are annoyed at the 'etics, then it'll need lining with that sheet, the front edge finished in a neat way, and then painting. That should be very easy to do, tho' awkward to get a neat finish between the unavoidable joins - unless the stove is first removed. That, too, should be 'easy', tho' it depends on how much play has been allowed for the flue - eg, can the collar be slipped upwards on the pipe enough to allow the stove to be pulled out? If so, this is a breeze.
Do you have the instructions for the stove? If not, you'll find it online. It should state the min gaps required. I can look later, but I suspect they are ok, or as near as. 

The above is largely guesswork, and totally my opinion. I did build a chimney breast for sil, to take a slightly larger, 5kW, fire, sides, top and front finished with a double skin of normal p'board, and finished in normal skim. No cracks, no issues. I did, tho', line the back with the heatproof board as per the instructions.