Wood burning stove fireplace, how deep is recommended?

[epsilonGreedy]

My brick laying team is nearly ready to build the basic structural skeleton of the fireplace and chimney above. The chimney breast is internal i.e. the outside wall is flat so the depth of the fireplace is formed by its intrusion into the room. The room is 17ft x 19ft and the width of the fireplace is decent at 1.6m.

 

The stoves I am looking at are around 400mm deep. We also like a higher than average mantle to give a hint of the inglenook fireplace style. 

Edited March 3, 2020 by epsilonGreedy

[Temp]

Check the building regs (Approved doc J) as they specify things like the gap behind a stove and the minimum projection of the hearth in front. So you might find the minimum depth is determined for you.

 

For ease of construction choose a stove with feet that the maker certifies cannot raise the hearth over 100C. Approved doc J is hard to follow until you realise some bits apply to stoves that are certified and others to stoves and fire baskets that aren't. 

[nod]

We did ours 600 deep 

While you cancan be restricted by how close to the back and sides you site the WB Purchasing a double skinned WB will allow to site it very close to the wall

Also worth remembering that the timber mantas is longer allowed to encroach int the chimney breast 

[Gone West]

10 hours ago, epsilonGreedy said:

The room is 17ft x 19ft and the width of the fireplace is decent at 1.6m.

Interesting mix of units. Which do you prefer working in? Although well into OAP years I now struggle with feet and inches whereas my mate converts metric to imperial before doing anything.

[epsilonGreedy]

22 minutes ago, PeterStarck said:

Interesting mix of units. Which do you prefer working in? Although well into OAP years I now struggle with feet and inches whereas my mate converts metric to imperial before doing anything.

 

 

Room size is still best visualized in feet in my head, whereas anything technical is metric.

 

Then there is ceiling height, I know my knuckles can touch a 2.2m ceiling whereas 2.4m is nicely out of reach.

[joe90]

32 minutes ago, PeterStarck said:

Interesting mix of units. Which do you prefer working in? Although well into OAP years I now struggle with feet and inches whereas my mate converts metric to imperial before doing anything.

ha, I do that, mix and match, I am of the age when the change to metric took place during my education. BUT you still buy carpet 3 or 4 meter wide but buy it by the foot ?.

[epsilonGreedy]

On 03/03/2020 at 06:07, nod said:

We did ours 600 deep 

While you cancan be restricted by how close to the back and sides you site the WB Purchasing a double skinned WB will allow to site it very close to the wall

Also worth remembering that the timber mantas is longer allowed to encroach int the chimney breast 

 

 

600 sounds about right.

 

We like this example from a Potton show home though without an external chimney breast we won't have anything like the same depth.

 

 

And here is another example, which also features a mantle beam installed above a typical height.

 

 

https://www.bookcottages.com/cottages/100-UKC1537-gorse-cottage.htm

[patp]

We, too, are at the stage where we need to choose our fireplace and woodburner options. Our chimney is going to be external and the brickie is asking us for dimensions of the internal part. This means we have had to go looking at woodburners. We have had one before in our old cottage but this is a new build so I am struggling to marry new fireplace with old style wood burner. The modern looking ones seem to all be sited free standing in a room. There is an amazing stove seller near us who has lots of makes to choose from but recommends Heta. Any one had a Heta? They do seem very good quality (Danish?). The array at the warehouse is immense. Went in looking for modern cylindrical and came out thinking of a more traditional style but with a log store underneath. The store gave sensible guidance on ease of opening the door and emptying the ash can for us oldies (cheek!). 

[joe90]

We found this one, traditional type but lovely colour

 

 

[epsilonGreedy]

In the end we treated ourselves to a short break in Ludlow and spent a few hours looking around the Clearview stoves showroom. The showroom is based in a Georgian era house which provided inspiration for the style of our newbuild, the staff there are very knowledgeable.

 

If depth constrained we noted that a stove can project 50mm forward of the face of the chimney breast.

 

The staff at clearview talked us down from a large stove and said anything over 8kw is nuts in a new build. Treat the low end of kW output ranges with a pinch of salt.

 

We demolished our first chimney breast and rebuilt after our showroom visit.

 

Have you sorted out the technicalities of the air feed?

[joe90]

1 minute ago, epsilonGreedy said:

treated ourselves to a short break in Ludlow

loverly place, I used to live in Shropshire. Did you visit the feathers? https://www.feathersatludlow.co.uk

[bassanclan]

You need to have a look if they do a direct air feed kit like this:

https://www.harworthheating.co.uk/product/ap-duns-107/

[patp]

On 03/11/2020 at 18:45, epsilonGreedy said:

Treat the low end of kW output ranges with a pinch of salt.

In what way?

 

The range of stoves in our local showroom (Natural Heating in Attleborough, Norfolk) is mind boggling. The proprietor is, however, very knowledgeable and told us about the gap needed behind each stove. They stock a British built stove that is certified to be sited 1mm to wallpaper! I wonder, though, if it is so well insulated that it will let out enough heat for a large room??

 

Thank you for the posting of photos of stoves in situ. Our chimney breast is external so we can have an inglenook style. I do get a bit hung up, however, on "keeping it modern" in a new build. We have always lived in old houses and taken pains to keep it authentic to the period that I struggle to think that I can use "old" in a new build.

[Ferdinand]

On 03/11/2020 at 18:04, patp said:

a more traditional style but with a log store underneath.

 

Is that known to be safe?

 

The log-burner in my previous house had been known to make wood put in the fireplace to dry finally start to smoke/smoulder when it was going flat out.

 

F

 

[epsilonGreedy]

2 hours ago, patp said:

In what way?

 

 

To kick start a wood burner into a good clean hot burn the stove will initially output near the top end of its quoted range. It will then be difficult to maintain a consistent burn at the low end range before you resort to opening windows to shed excess kW.

 

Clearview have a strong opinion on this to the point of losing sales of larger models.

Edited November 5, 2020 by epsilonGreedy

[joe90]

22 minutes ago, epsilonGreedy said:

before you resort to opening windows to shed excess kW.

I have never had to do this, with internal doors open and lots of thermal mass (?) to absorb the heat it dissipates nicely around the house and is still warm come the morning.

[MarkyP]

We've recently decommissioned our wood burner - it's a 5kw Morso in a 40m2 room which is very airtight, 3g and insulated with 250mm combo of EWi and cavity fill. The room massively over heats very quickly and we end up letting it go out an hour after lighting so I took it out. The interior air quality issues as well - read various Danish studies on the impact of opening stove door to light or refuel on indoor air quality - eye opening.

[ProDave]

31 minutes ago, joe90 said:

I have never had to do this, with internal doors open and lots of thermal mass (?) to absorb the heat it dissipates nicely around the house and is still warm come the morning.

+1

 

With a central stair well with double doors either side to the two living rooms, with the doors open the heat circulates around the whole house and some goes upstairs as well.

 

Agreed if you have a stove in just one room with no other place for the heat to usefully go, then you would overheat a single room quickly.

 

 

[patp]

We have a traditional brick and block build. Will that absorb heat more than a timber frame?

[Temp]

On 03/11/2020 at 18:04, patp said:

The modern looking ones seem to all be sited free standing in a room.

 

The Clearview Solution 400 fits with both old and modern styling. Love ours. Its possible to control the air so you get lovely slow flames and the glass doesn't tar up as fast as other makes.

 

Ours is in a traditional recess with the chimney to one side.

 

[Temp]

I believe Clearview have a direct air kit for some of their stoves but last time I looked they had two vents on their stoves, one on the bottom that could be fed from outside air and one on the door that took in room air. This might have changed as its been awhile. Ours burns room air.

[ProDave]

20 minutes ago, Temp said:

I believe Clearview have a direct air kit for some of their stoves but last time I looked they had two vents on their stoves, one on the bottom that could be fed from outside air and one on the door that took in room air. This might have changed as its been awhile. Ours burns room air.

That's referred to as Primary and Secondary air. and some makes of stove that claim ducted air intake that only applies to one.

 

I can confirm our Mendip Stoves Churchill does take both primary and secondary air from the inlet duct and that appeared to be a standard fitment, not a bolt on extra kit.

[patp]

We were told that a well sealed modern house may not produce enough room air to feed the stove and external air should always be considered. This need not be fed straight into the burner but may be provided by an air brick in the room.

Edited November 5, 2020 by patp

[ProDave]

2 minutes ago, patp said:

We were told that a well sealed modern house may not produce enough room air to feed the stove and external air should always be considered. This need not be fed straight into the burner but may be proved by an air brick in the room.

If you have a stove of 5kW or more, that draws it's combustion air from the room, then you must have a vent of a certain size to let fresh air into that room.

 

Clearly if you have gone to the trouble of making a house air tight (and installed mvhr?) you don't then want to be making a big hole to let air into the room, so a room sealed stove is pretty much essential.

[patp]

We have trickle vents in our windows. I assume that will be enough?