Chimeny Renovation

[john2502]

Hi All

First post here so go gentle! We're currently in the process of sorting out our front room wood burner and could use a little advice if ok. The story so far.....

Apart from a few times when we first moved in 7 years ago we've never used the current woodburner, the few times we did we really couldnt get any heat out of it suspecting due to it having no air around it as they had boxed it in way too tight with the stone (fire was burning nicely just hardly any heat from it going into the room)

Anyway fast forward and we'd like to install a nice new little 5KW wood burner in the space, ideally having plastered chimney at the front, original brick surround in the fireplace opening if it's in reasonable condition and a porcelian tile hearth base. So we've removed the ugly 70's stone surround and were going to start widening the opening but we are now concerned about what part is structural.

There is a metal lintel but it doesnt run as wide as i expected it to so am concerned if i open it up we might cause an issue. Have attached an image of the current situation and added in red a line where the metal lintel runs from to. I am thinking we may need a new longer lintel installed for the opening but am no expert so advice would be great. Being very cautious as with 2 younf children in the house really didnt want to make the front room dangerous in any way.

Thanks in advance for any help/advice

John

 

[Ashful]

Your assumption about lack of heat is correct. A stove that radiates heat off the sides and back will put very little heat into the room, if surrounded by stone. I had the same situation (x2) in my house, you can see one of them in my avatar photo. I assume the stone surround you describe was once more than what you show in this photo, I can see what appears to be the remains of it.

For the replacement stove, if you will again have a surround or if you have a lot of exposed masonry in the room, should be a design with a high convective factor. OTOH, if you will stay without a masonry surround that there's no other masonry than that rear wall, any stove with a low rear clearance (meaning it doesn't put a lot of heat off the back) will do fine.

As to structural issues, you do have a bit of an issue, there. In a wall of sufficient width, when removing a lintel, you will typically lose a few courses of stone only in the middle of the span. It will form a natural arch, with the stones above holding in place due to the (equal and opposite, thanks to Newton's 2nd) horizontal forces applied by the surrounding wall. However, you have a narrow structure, so with the proposed opening being nearly as wide as the structure, there is some possibility the outward forces created by the naturally-forming arch could cause the side walls to buckle and fail.

Truthfully, if you hire a professional mason, I suspect they're likely to just pull the lintel and do the proposed work, without any secondary bracing. They're insured, and equipped with the knowledge and tools to rebuild the whole darn thing in the probably-unlikely event that there is a major failure during the short time the lintel is removed for replacement. But if I were doing it myself, I'd fashion some sort of temporary structure, likely just a vertical timber on each side of the fireplace, held together with a few bar clamps, to hold the sides from shifting outward during the lintel replacement.

 

[john2502]

Thanks so much for your detailed response, it really is appreciated.

Yes I hadn't considered the horizontal load placed on the sizes pushing out, as you say needs to be taken into consideration and I will mention this as i think we'll need new lintel installing as soon as possible before continuing.

So strange to have half a row of what look like soldier bricks a little further up too, not sure if that was part of an original opening at some point but the bricks on the left hand side then don't line up to that.

Attached a nice before, during, and after demolition of the stone fireplace surround and TV stand, man there was a lot of rubble in there! As well as the kind of thing we're hoping to achieve.

Our local Fireplace installer said a MI Fires Skiddaw would be a decent fit without breaking the bank, so i think this is the plan:

1. Widen opening and install new lintel (professional to do this)
2. Remove old burner (me)
3. Inspect fireplace opening brickwork and asses if suitable to leave exposed, if not board this up with suitable boards and/or repair (me or professional if not in usable condition)
4. Tile base with suitable porcelain tiles (me)
5. Install new wood burner and potentially new flue liner (professional)
6. Plaster chimney breast (professional, the rest of the room is being done in a few weeks so will get this completed at the same time)
7. Paint chimney
8. Sit back and relax and hope the budget wasn't too bank breaking

 

[EbS-P]

How far out were you wanting the stove to sit? I have an internal chimney and I decided to set mine as far back as I could so I would not need ember protection on the floor. It’s not an ideal arrangement for heat. I need a blower. My recommendation bring the stove out as far as practical. Adding a blower is helpful. Mine stove didn’t have that as an option I just set one behind it blowing up the back.

It takes a good 2 hours of burning for my masonry to start to warm up. Even then it takes 12 hours for it to really heat soak and for the stoves full output to really be felt in the space.

 

[Ashful]

Hey EbS-P, I had two Jotul Firelight 12's (the great-grand-daddy to your F400) sitting way back inside fireplaces, and I'll agree that those radiant cast-iron Jotuls will perform poorly if surrounded by masonry. So much of the heat radiated off the sides and top are soaked up by the surrounding masonry, and if it's on an exterior wall, that ends up radiated outside. On the flip side, if it's completely interior masonry, such as a central fireplace in a New England home, I suppose it could act a bit of a poor-man's masonry heater.

But stoves wearing a convective jacket, essentially a box within a box with forced air thru a gap, can perform nearly as well set back inside a fireplace as it does out in the open. This is the case with my BK Ashfords, which put so little radiant heat off the sides and top that I can touch them when the stove is running at my normal setting. So, if re-building a stone surround, I'd definitely recommend going with a stove that has a convective jacket design.

As to brands and models, I'm guessing there are a lot in the UK that those of us in the US won't recognize, but there are other UK members of this forum who may help, there. Likely, your best bet is to visit a few different stove dealers local to you, to see what brands they carry or support, and to mention you want a stove with clad box convective design.

If none of this makes sense to you, check out the BK Ashford 30, or the PE Alderlea. You'll see both have a welded steel firebox, with decorative cast iron panels hung on the outside of it. Both rely on natural convection between the steel firebox wall and the cast decorative panel, to move heat off the stove and into the room. At least with the BK Ashford 30, there's an available fan kit to really amp up the convective factor, I suspect PE may offer the same for the Alderlea.

 

[begreen]

If none of this makes sense to you, check out the BK Ashford 30, or the PE Alderlea.

They are larger stoves that wouldn't fit in this location. This is a different market and application. Either of those stoves would probably cost more than the entire job in the UK, if they could be found there. The MI Fires Skiddaw can be bought for under £600.

 

[Ashful]

They are larger stoves that wouldn't fit in this location. This is a different market and application. Either of those stoves would probably cost more than the entire job in the UK, if they could be found there. The MI Fires Skiddaw can be bought for under £600.

For the record, I wasn't recommending either of these stoves for the OP. I was simply citing them as two good examples of stoves with convective jackets, in case my description of the technology did not make sense.

I assume they'll want to shop for stove widely available in the UK, and supported by their local installers.

 

[begreen]

I'm not sure that the new stove will produce more heat than the old one, but it looks like it will burn cleaner and has a nice clean look. The design appears to be one that will project the heat forward into the room, so that could be a plus. Let us know how it works out.

 

[Ashful]

Whatever stove you go with, remember that you may be married to the house, but not the stove. Set things up right, and you'll find you can pretty easily swap stoves, if your first choice isn't performing as expected. At least on this side of the "pond", stoves can be re-sold with a pretty modest lost, making swapping stoves a pretty small matter if the rest of the system is set up to allow for it.