ziplex Posted September 7, 2011 Report Share Posted September 7, 2011 Our woodburner has been in since early in the year and it's been great but......the stove itself sits within the original fireplace that previously housed a gas flame fire which was then opened up after removal to accomodate the new stove. So.....the stove is sitting pretty but the previous owner built a large fireplace surround from brick in front of the original fireplace and i'm wondering if this has too much of a negative effect on the heat output? The brick 'arch' stands about 18" above the top of the stove but forward of it by approx' 12", in other words the stove is sort of encased in brick from both the sides and above. I was thinking of removing the 'add on' fireplace/mantlepiece but can't make my mind up If the stove top was slightly in front of the original fireplace as opposed to within would the heat output be significantly different do you think?? I've re-read this a few times now and I think it makes sense Quote Link to comment Share on other sites More sharing options...
twitchynik Posted September 7, 2011 Report Share Posted September 7, 2011 Makes sense. I've been reviewing my current install as I think the stove is too small and not chucking out as much heat as I'd like. The only thing you need to be wary of is the distance from front edge of the stove to the front of the hearth. This, according to building regs must be at least 225mm. I've been reading and re-reading those bloody regs as I want to put a bigger stove in but I'm not sure that the one I want in will fit. There are also considerations for the gap between the sides of the stove and the fireplace (150mm) and the top of the stove and the fireplace which I can't recall. Anyway, by the sounds of what you're describing those aren't a concern. I don't think there is any mention of the top of the stove being completely within in (under) the fireplace. Here's the regs document if you fancy a good read...! http://www.planningportal.gov.uk/uploads/br/BR_PDF_ADJ_2010.pdf Quote Link to comment Share on other sites More sharing options...
DSPUK Posted September 7, 2011 Report Share Posted September 7, 2011 In an ideal situation the stove should be free standing with nothing around it -- At my old house I had it in a large inglnook and it was more than capable of heating a 15x27 room but it did run one rad in room as well + 5 other rads -- Now in this house I did same as your last owners and knocked fireplace out and set woodburner in - even though it sits in- it is still able to make the room more than hot if you feed it. dave Quote Link to comment Share on other sites More sharing options...
ziplex Posted September 7, 2011 Author Report Share Posted September 7, 2011 Makes sense. I've been reviewing my current install as I think the stove is too small and not chucking out as much heat as I'd like. The only thing you need to be wary of is the distance from front edge of the stove to the front of the hearth. This, according to building regs must be at least 225mm. I've been reading and re-reading those bloody regs as I want to put a bigger stove in but I'm not sure that the one I want in will fit. There are also considerations for the gap between the sides of the stove and the fireplace (150mm) and the top of the stove and the fireplace which I can't recall. Anyway, by the sounds of what you're describing those aren't a concern. I don't think there is any mention of the top of the stove being completely within in (under) the fireplace. Here's the regs document if you fancy a good read...! http://www.planningportal.gov.uk/uploads/br/BR_PDF_ADJ_2010.pdf It's all been installed within spec' Quote Link to comment Share on other sites More sharing options...
ziplex Posted September 7, 2011 Author Report Share Posted September 7, 2011 In an ideal situation the stove should be free standing with nothing around it -- At my old house I had it in a large inglnook and it was more than capable of heating a 15x27 room but it did run one rad in room as well + 5 other rads -- Now in this house I did same as your last owners and knocked fireplace out and set woodburner in - even though it sits in- it is still able to make the room more than hot if you feed it. dave Dave, mine would be sort of like the one in the second pic'......exept the brick fireplace is over and in front of the top of stove. I'm thinking the heat that radiates from the top of the stove is being blocked by the bricks from entering the room? Quote Link to comment Share on other sites More sharing options...
-Mongrel- Posted September 7, 2011 Report Share Posted September 7, 2011 So long as you have closed the chimney off around the flue just above the mantlepiece height then I'd not expect much negative effect to be honest. The heat would rise but with nowhere to go would then find its way out. Quote Link to comment Share on other sites More sharing options...
DSPUK Posted September 7, 2011 Report Share Posted September 7, 2011 Zip Providing the top underside is flat the heat will just come out - if you have a lip maybe not -- in the second pic that is a steel box with angle iron welded to front - the angle part is the side edges and are plastered into walls - Once it was in it became apparent that box got very hot even though on inside it is surrounded by Vermiculite - but wall got very hot at back - so I had a piece of steel sheet cut to fit width but 2" shorter top to bottom - That was bolted to back of box but spaced out 20mm and 25mm gap top and bottom - this in effect caused air to circulate round back of steel sheet and created a airflow - back wall is cool and heat is great. it is on at moment as it seems quite cool out. Dave Quote Link to comment Share on other sites More sharing options...
ziplex Posted September 7, 2011 Author Report Share Posted September 7, 2011 (edited) Zip Providing the top underside is flat the heat will just come out - if you have a lip maybe not -- in the second pic that is a steel box with angle iron welded to front - the angle part is the side edges and are plastered into walls - Once it was in it became apparent that box got very hot even though on inside it is surrounded by Vermiculite - but wall got very hot at back - so I had a piece of steel sheet cut to fit width but 2" shorter top to bottom - That was bolted to back of box but spaced out 20mm and 25mm gap top and bottom - this in effect caused air to circulate round back of steel sheet and created a airflow - back wall is cool and heat is great. it is on at moment as it seems quite cool out. Dave ........here, just took a pic', the brick arch above is way out in front of the top/front edge of the stove, do you think that may sap some of the heat? Edited September 7, 2011 by ziplex Quote Link to comment Share on other sites More sharing options...
ziplex Posted September 7, 2011 Author Report Share Posted September 7, 2011 So long as you have closed the chimney off around the flue just above the mantlepiece height then I'd not expect much negative effect to be honest. The heat would rise but with nowhere to go would then find its way out. There's a fully sealed register plate at the base of the chimney opening....the underside of the bricks get quite hot but the heat you might expect to rise doesn't? are the fans advertised worth a punt to push the hot air out? Quote Link to comment Share on other sites More sharing options...
twitchynik Posted September 7, 2011 Report Share Posted September 7, 2011 Might be worth calculating the volume of the room and and finding out what Kwh output the stove is rated at. Although there are standard calculations which recommend how large or powerful a stove you should install but in real life (what you feel when your sat on the sofa watching X Factor on the box) you'll probably want a bigger stove. That's certainly what I've found after two winters and why I'm putting a more powerful one in but still making sure there's enough airflow to get the best out of it. Quote Link to comment Share on other sites More sharing options...
-Mongrel- Posted September 7, 2011 Report Share Posted September 7, 2011 ........here, just took a pic', the brick arch above is way out in front of the top/front edge of the stove, do you think that may sap some of the heat? Well yes...and no! The bricks are bound to absorb some of the heat, however, of the overall heat provided I'd not think it would be enough to make a noticeable dent in the output, add to that the bricks will then also act as mini radiators once they are warmed then your losses are reduced further (the heated bricks are basically how storage heaters work, they take in the heat and then slowly release it over a period of time). Adding fans would work...how effectively I don't know but fan heaters are more effective than plain convector heaters, whether the cost of running fans would offset the heat benefit I'm afraid I also don't know. Quote Link to comment Share on other sites More sharing options...
DSPUK Posted September 7, 2011 Report Share Posted September 7, 2011 I suppose the one question we haven't asked is how big is room and what is output of fire - the first pic of mine shows a Clearview with 14kw output - second is 4.5Kw output and room is half size of my old one - saying that this fire will make you take your shirt off if you load it. Even the cat can't stand heat for long. - What you can't see on mine is room goes round chimney brest to dining room and I now have a vent from dining room into fireplace behind steel sheet - it helps the flow of air out of box. - heat and convection and all that. Is your fireplace as big as it looks ?? and what make of fire do you have/output/size - in the end it all adds up. Dave Quote Link to comment Share on other sites More sharing options...
Fisherman Mike Posted September 7, 2011 Report Share Posted September 7, 2011 Looking at the photo it wont make any difference to the heat loss. Have you a register fitted or does the flue go straight into the existing chimney liner with a short length of enamel? If so get a register plate fitted or 30% of the heat is going straight up the chimney. I would be tempted to keep those logs well away fron the body of the stove though as they dry out and the stoves get hotter.....well you can guess the rest... Not common but two recorded cases of fire caused this way in the last 6 years locally Quote Link to comment Share on other sites More sharing options...
ziplex Posted September 7, 2011 Author Report Share Posted September 7, 2011 It is a big old fireplace and that's the main problem, we're thinking of removing it and looking for excuses to do so......one day we think it looks fine, the next we want it gone The stove itself is ok for the room, and was the right output after the calc's were done, but like you say it has to be stoked and get it roaring to be really effective when it's very cold outside. If there would be a benefit in removing it's 'roof' then the stove could burn a little slower perhaps. When it's on song even the ever shivering GSP tends to move away and slump somewhere cooler. Quote Link to comment Share on other sites More sharing options...
ziplex Posted September 7, 2011 Author Report Share Posted September 7, 2011 Looking at the photo it wont make any difference to the heat loss. Have you a register fitted or does the flue go straight into the existing chimney liner with a short length of enamel? If so get a register plate fitted or 30% of the heat is going straight up the chimney. I would be tempted to keep those logs well away fron the body of the stove though as they dry out and the stoves get hotter.....well you can guess the rest... Not common but two recorded cases of fire caused this way in the last 6 years locally They won't be that close come fire up time, I did make the mistake of leaving a small log on the top earlier in the year, went into the kitchen for a short while and walked back into a room full of smog Quote Link to comment Share on other sites More sharing options...
ksharp Posted September 7, 2011 Report Share Posted September 7, 2011 What if you changed the flue so it came out the back outlet instead of the top? It would bring the fire forward a bit Quote Link to comment Share on other sites More sharing options...
ziplex Posted September 7, 2011 Author Report Share Posted September 7, 2011 What if you changed the flue so it came out the back outlet instead of the top? It would bring the fire forward a bit Good point and I did think of it but it's as close to the front of the hearth as is permissable in order to be 'in spec'......knowing my luck if the place burnt down that would be the first thing they'd check and pull me on it Quote Link to comment Share on other sites More sharing options...
gixer1 Posted September 7, 2011 Report Share Posted September 7, 2011 Could you knock through so both sides are open around the stove?? Quote Link to comment Share on other sites More sharing options...
ziplex Posted September 7, 2011 Author Report Share Posted September 7, 2011 Could you knock through so both sides are open around the stove?? No gix' it's a supporting wall, just pulling out the filled in areas aroung the previous gas fire brought me out in a cold sweat... i'd been reliably told it was safe to attack but was convinced the chimney was going to collapse on me Quote Link to comment Share on other sites More sharing options...
gixer1 Posted September 7, 2011 Report Share Posted September 7, 2011 No gix' it's a supporting wall, just pulling out the filled in areas aroung the previous gas fire brought me out in a cold sweat... i'd been reliably told it was safe to attack but was convinced the chimney was going to collapse on me Mine us a supporting wall but it just meant concrete reinforced lintels needed put in...it obviously ups the efficiency about 100% Quote Link to comment Share on other sites More sharing options...
ziplex Posted September 7, 2011 Author Report Share Posted September 7, 2011 Mine us a supporting wall but it just meant concrete reinforced lintels needed put in...it obviously ups the efficiency about 100% Really is more a question of whether or not to remove the brick fireplace with ours, if the efficiency may of improved it would of helped in making the decision. Do like the look of yourn... Quote Link to comment Share on other sites More sharing options...
sandspider Posted September 7, 2011 Report Share Posted September 7, 2011 My stove sits in an alcove a bit like yours and has a lip in front of part of the stove (wooden mantelpiece). It does get very hot up there (the bricks and mantelpiece heat up too) but judging by the movement of a cobweb behind the mantelpiece there's a fair bit of air circulation so the heat does get back out again! (Then again, it's a bit stove in a smallish room so there's probably heat to spare...) Quote Link to comment Share on other sites More sharing options...
sandspider Posted September 7, 2011 Report Share Posted September 7, 2011 Come to think of it, my stove has a cowled top rather than a flat top - maybe that helps to kick some of the heat out. (But it does mean I can't put a kettle on top!) Quote Link to comment Share on other sites More sharing options...
al4x Posted September 8, 2011 Report Share Posted September 8, 2011 simply it makes a big difference sitting it back in the fireplace, first thing I would do is remove the brick surround and modify the hearth so it was fully legit to have the stove with a rear entry flue. Its interesting with fires I've always been sceptical about surrounding the sides and rear with the insulating bricks and talking to a guy selling stoves at the weekend it seems they have sussed this and the newer generation are starting to do away with them. My mum has a logburner mounted fully in front of the chimney and that gives a superb amount of heat and being side loading no real problem with hearth size. I'm currently modifying a fireplace in my new house and have knocked it now back to the original lintle and have a cracking space. Got no photos of the finished deal but this one shows how much t had been blocked up as all that came from round the gas fire that was there when we bought it Quote Link to comment Share on other sites More sharing options...
twitchynik Posted September 8, 2011 Report Share Posted September 8, 2011 What size (dimensions and output) stove you planning on putting in there Alex? That space looks very much like what I have (mines maybe a bit wider and deeper) and currently there's a 4Kwh stove in which I think is underpowered. Granted there's no door between the room it's in and the next room so there's a lot of heat going out the room but I'm ok with that and another reason why I want a more powerful one. Quote Link to comment Share on other sites More sharing options...
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