Wood burner install / ideas

[David West]

Hello everyone, I’ve read this forum for a while now and am looking for points / ideas / recommendations for a wood burner in my summer house ( I’m in Scotland).  My outdoor building is about 33 meters from the main house with its own electrical supply installed.  Thing is, it’s a bloody nightmare to heat! I currently have a 3kw electric convector heater running when I’m down, but it’s not doing the business and I’d always fancied a wood burning stove down there.  I built the house myself and will be doing the work myself.  The building itself is pretty well insulated with kingspan floor and ceiling, walls with rock wool.  The size is about 6m by 4m , finished inside with laminate flooring, gyproc walls and mdf skirting.  I have an area looked out and am currently putting together a list of what I’d need.  I realise I need the twin walled flue from the burner outside, but I’ve a few questions I’d like to put to you all.  Should i be looking for a rear or top entry stove? If I get both is one ‘better’ than the other? As it goes outside I’m thinking of a tee of sorts to allow inspection cleaning.  The roof is flat and I recon the flue will be about 3m or just under from the stove if I’m assuming a height of 500mm from inside.  I rather not go straight up as it’s a rubber epdm roof, does anyone have experience with this? Am I better to go straight up?  I spoke with a guy on the phone from a stove shop last week who recommended no bigger than 5kw.  I read that combustible materials should be no less than 3 times the diameter of the stove pipe, I have a tv on the wall which will be about 650mm from side of stove position, do any of you have items this close?  Sorry about the amount of questions but thought this would be a great place to start, the information given here from the wealth of knowledge is priceless imo.  I’ve uploaded a pic of where I’d like to install, sockets / lights can be moved to suit so that’s not a problem. 
 

David 

[openspaceman]

In England you should comply with building regulations, part J deals with stoves and flues:

 

Approved Document J | Part J - Combustion appliances and fuel storage systems | Planning Portal

WWW.PLANNINGPORTAL.CO.UK

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Details of Part J (Approved Document J) of the Building Regulations

 

I doubt Scotland is much different.

 

As for choice of burner I have experience of very few but the modern ones approved by defra and meeting the latest standard are the ones to go for, I'd avoid cheap steel or cast iron boxes. Prior to my current Morso 11 I had a Jotul 602 and the Morso is so much better, especially because of the radiant heat given off by the ceramic glass door.

 

@Alycidon knows about what is on the market.

 

 

[Alycidon]

Hi,

 

 I own two retail stove showrooms and have been advising people about stoves for about 12 years.

 

I can though only comment on the regs as they stand in England,  approved Doc J 2014, the front part only as openspaceman has advised.  

 

Summer houses, sheds, log cabins etc do not come under building regulation above with regards to the install of a stove.  None the less it needs doing properly and above all safely. Thus I would recommend you abide by the building regs.

 

The major issue you have is a wooden floor and probably plasterboard walls and ceiling.  These are all viewed as combustible.  

 

So let's deal with the easy bits first. 

 

Where you want to put the stove is fine given that its either far enough away from the combustible walls or steps are taken to fire rate the walls in the area of the stove.  Stove manufacturers will usually advise their minimum required clearance to combustibles in the technical notes on their web sites.

 

You will need a non combustible hearth to stand the stove on,  the thickness of this hearth on most good quality modern design stoves is a minimum of 12mm.  Anything that is non combustible can  be used,  looking at your floor then a glass hearth would work well. 

 

Most stoves work through a process of radiation, the flames heat the metal of the stove body, this then radiates that heat into the room.  However the sides get very hot, thus needing quite a large minimum clearance to combustibles.  You could use a convector stove,  this radiates heat to the front and top but the sides and sometimes the rear have air gaps between the side of the firebox and the side of the stove itself. Cool air from the room is drawn in the base of the convection chambers under the stove, rises up via convection and emerges from slots on the top of the stove as heated convected heat.  Two benefits, a. Slightly better efficiency  and b, reduced minimum side clearance to combustibles.   My first choice stove for this type of application is the morso S11 series,   morso also do a fully insulated flue system for use in cabins etc but it's only approved for use with their stoves.  The flue route with the morso system would be straight up through the roof.

Charnwood have recently released their stove pod system for use in conjunction with their Aire3 stove,  only 50mm clearance to combustibles from the outside of the pod,  the base of the pod is also a legal hearth. A very neat installation specifically designed for this type of install

.

 

PM me your e mail address and I can send you links if you wish.  

 

Hope that helps. 

 

A

 

[Dan Maynard]

Unless there is no room outside the building I think it's less trouble to go through the wall at 45deg and up, less chance of weather leaks, all in a twinwall system to avoid any problems with combustibles. Needs to be designed correctly though, when we had ours done we got someone else to work it all out.

[David West]

That’s for the replies, I’ve pm’d you alicydon,  I’ve got my eye on a nice glass 12mm hearth. The ceilings are 2.4m high, would I need to watch this in terms of heat given off by a stove?

Edited February 3, 2021 by David West

[Alycidon]

Work out the volume of the room in cubic meters,  roughly.

 

say 5m x 4m x 2.5m =  50 cubic meters,

 

Then divide by 12 for poor insulation ( so 4kw),  14 for average insulation ( so 3.5kw)   or 16 for good insulation ( so 3kw),  that is the amount of heat you would need in total to get the temp in the room to 22 Deg C if its 1 deg c outside.    If the window of glass area is larger than average then add in extra heat as heat loss through glass is a lot worse than through a solid wall.

 

The rated output of a stove is what is known as a nominal output,  the actual output will depend on the fuel you load and what volume of fuel you load.    A 5kw nominal wood burner has a typical output rage varying from about 2kw up to 7kw.  

 

For optimum performance choose a smaller stove that is working flat out all the while,   it burns cleaner,  keeps the glass clear and gives you a nice flame picture.  

 

Glass hearth needs to be large enough to conform to the regs,   in a corner then a tear shape would usually work but talk to your installer about what sie you will need,  this will depend on the size of the stove you select and what is happening about the side walls of the cabin re fire proofing.   (Are you siting the stove outside the Min Comb clearance of the stove or are you making the walls fire resistant perhaps with fireboard ( Not the pink backed stuff).

 

Here are the links.

Stove Pod - Charnwood Stoves

WWW.CHARNWOOD.COM

 

Morsø S11-42

MORSOE.COM

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The elegant, simple design of our S11-42 multi-fuel stove really shines.

A

[Ratman]

Work out the volume of the room in cubic meters,  roughly.
 
say 5m x 4m x 2.5m =  50 cubic meters,
 
Then divide by 12 for poor insulation ( so 4kw),  14 for average insulation ( so 3.5kw)   or 16 for good insulation ( so 3kw),  that is the amount of heat you would need in total to get the temp in the room to 22 Deg C if its 1 deg c outside.    If the window of glass area is larger than average then add in extra heat as heat loss through glass is a lot worse than through a solid wall.
 
The rated output of a stove is what is known as a nominal output,  the actual output will depend on the fuel you load and what volume of fuel you load.    A 5kw nominal wood burner has a typical output rage varying from about 2kw up to 7kw.  
 
For optimum performance choose a smaller stove that is working flat out all the while,   it burns cleaner,  keeps the glass clear and gives you a nice flame picture.  
 
Glass hearth needs to be large enough to conform to the regs,   in a corner then a tear shape would usually work but talk to your installer about what sie you will need,  this will depend on the size of the stove you select and what is happening about the side walls of the cabin re fire proofing.   (Are you siting the stove outside the Min Comb clearance of the stove or are you making the walls fire resistant perhaps with fireboard ( Not the pink backed stuff).
 
Here are the links.

Stove Pod - Charnwood Stoves

WWW.CHARNWOOD.COM  

Morsø S11-42

MORSOE.COM

---

The elegant, simple design of our S11-42 multi-fuel stove really shines. A

Stove pod looks well [emoji106]

[Alycidon]

1 hour ago, Ratman said:

Stove pod looks well

Its an ideal package solution,  state of the art Charnwood wood burner in it,   so high quality and long life.   

 

A

[scbk]

On 03/02/2021 at 15:20, David West said:

  Thing is, it’s a bloody nightmare to heat! I currently have a 3kw electric convector heater running when I’m down, but it’s not doing the business and I’d always fancied a wood burning stove down there.  I built the house myself and will be doing the work myself.  The building itself is pretty well insulated with kingspan floor and ceiling, walls with rock wool.  The size is about 6m by 4m 

As someone who's used to drafty cottages and the like, I would've thought a small well insulated space like that would be very easy to heat?! Do you heat the main house with wood - do you already have a supply of logs & woodshed?

[David West]

18 minutes ago, scbk said:

As someone who's used to drafty cottages and the like, I would've thought a small well insulated space like that would be very easy to heat?! Do you heat the main house with wood - do you already have a supply of logs & woodshed?

The issue is, when I use the heater, it takes hours, I understand the wood burner will take time too, but I just can’t get it out of my head the waste in energy, to heat it.  A wood burner has always been on my mind down there.  I have a large stock of wood drying in my back garden, must be about 2 years now, no stove in the main house yet, will see how this one goes.  Picked up a 12mm large glass hearth today, this installation begins!!!

Edited February 4, 2021 by David West