Is it possible (or rational) to build a wood burning fireplace with a stone or brick chimney in a house that did not originally have one? Can you safely cut through a roof and build out a chimney without too much damage or subsequent water damage if properly sealed?
On Sat, 27 Feb 2010 15:19:23 -0500, Rex Mundi wrote Re Building a fireplace:
Possible: Yes Rational: No, because of costs.
Sure it is both possible and rational if you know how. I have done hundreds of fireplaces in existing homes but it is not cheap.
The short answer: It is going to be costly to retrofit. Yes, you can safely cut the roof and have it sealed properly. If done right, there should be no leaking. The amount you have to demo depends on your house and its configuration. If you have the skills, you can DIY on parts of it.
Read further for the long answer.
I do not want to piss on your parade, but will share my own experience.
I built a beautiful two sided massive fireplace in a home I built. After, I discovered it was a waste of money.
Not a lot of heat is produced by a fireplace, and I mean a fireplace that has no metal box configuration, only made of firebrick, stone, brick, whatever. It goes right up the flue, and yes, I know we will hear from a lot of people who will swear and avow that THEIRS is somehow magical and heats their entire house.
Facts are a little different.
Fireplaces need air to burn, and mostly that comes from the room in the air. On mine, I had to have a window open for it to work properly. Some fireplaces can be made to take air in and provide their own air. Still, there's a hole there, and after you've gone to bed and the fire goes out, all the warm air rises to escape. So not a lot of net heat gain.
I have wood stoves at my current residences. They can be bought where they have a double stack where one pipe is inside another. One draws combustion air, the other exhausts gases. They just give off heat without using room air. Lots of stoves for lots of prices and lots of degrees of efficiency. Problem is that you have to buy them and use them and see just how they work in YOUR house.
My BIL has a beautiful massive fireplace that they rarely use because it smokes into the house so much. Oh, I know I'm gonna hear that it's improperly this and that, but in reality, no fireplace works without leaking smoke into the house. If you look at very old historic places, the fireplaces are usually rock, and have soot to the ceiling. He has to cut his wood very small, as not enough heat is generated to keep larger pieces burning. That goes through wood fast.
Having a fireplace is work. Cleaning. Getting wood. The mess of it all. Alternatives are only slightly better, but give off more heat more efficiently.
I'd rethink the fireplace thing, or if you do, have a contained firebox in there so at least you will get some heat out of it efficiently instead of only having an attractive nuisance.
Then there's the downside. A house down the street has burned down twice now with fireplace incidents. They musta got a ton of money the first time, because they did it with a lot of copper on the outside, and really really nicer than the original house. Now, it's all melted. With pellet stoves or good wood burners, at least you can eliminate some of the hazard with correct piping of insulated pipes. Use a clay flue, even if you have the two layer pipe. Other than liner fires, lots of fires are caused by heat transfer to adjoining materials. A flue would give you another layer, and bricks/blocks yet more insurance.
Don't forget you have to get it chimney swept occasionally to avoid fires within the ducting from buildup.
Good luck.
Steve
If you can dream it, you can do it...
BUT, check with your insurance agent, perhaps expect higher costs on the premium.
My insurance agent says that to put a wood stove in my trailer would double or triple my home owner's insurance. Fireplace in a frame home, likely not a lot of rate increase.
Rex Mundi wrote in news: snipped-for-privacy@4ax.com:
People have said a lot in their replies and I tend to agree with it. I constantly read about the inefficiency of them. Big business selling items to improve the efficiency - inserts, blowers, doors, etc. To me it's like building a $5k+ hole in the wall.
If the reason is romance, impressing people or you just like the way it looks and it's worth the bucks to install with ongoing maintenance (heat loss then by all means go for it. It's you $ and you earned it.
Depending on the size of the room, you often lose a whole wall of practical usefullness.
I know nothing about building a FP but I'm surprised the people who have replied and appear to have some knowledge didn't remind you of a foundation and footer for it. Those bricks weigh a lot. The depth of the foundation depends on where you live/the frost line. My understanding is the fireplace footing should be the same as the house footing depth.
It MUST be solid and not move. Like I said, I know nothing about FP's but some rusty geometry tells me this. The bricks on the outside of my inherited chimney extend about 24" from the house so I'm guessing another
6" through the wall and where they end inside not counting outer hearth.If the foundation is 30" in length and it were to drop a mere 1/8" at the outside edge that means the chimney would pull away from the house. Let's say it connected to the roof at 12'. The chimney would move away from the house over a half inch at 12'. It MUST be solid.
I've been meaning to put one of those shrink-fit window seal kits over the front of my fireplace doors since I moved in 4.5 years ago. It is one of those metal prefab fireboxes with a wood chimney stack (the inside brick is purely decorative), so I'd have to pay to have a pro check it out before I would dare to use it. No SWMBO in the house, and I have allergies anyway, so never seemed worth the bother. We had fireplaces when I was a kid, and I do like them, but unless they are very carefully engineered (and few are), they are a major heat suck for a house with central HVAC. Drafty houses from the old days always had enough air coming in to support combustion, but with a modern house you really need an outside air intake, like with a wood stove. The firebox has to be shaped correctly, as does the plenum, for them to draw correctly. And unless you have an thermally-connected exposed wall of stone or brick that can warm up and radiate back into the house, most of the heat is wasted. That is why old houses had the fireplace in the center, with a cooking hearth on one side, and the show-off fireplace on the other, using the same chimney stack. The fireplace WAS the furnace. They also had huge floor grates in second floor to warm the upstairs, something fire code won't allow today.
-- aem sends...
We added a wood burning stove. It went up an OUTRAGEOUS $25 a year on our homeowner's insurance. It depends on your company, as others pay $300 for same.
Steve
What Steve says is correct. You also need to put in an air supply pipe from the outside to a point as near to the fireplace as possible . If you have a basement this is fairly easy, if the floor is solid then it's a may be a major problem. A piped air supply stops cold draughts fro crossing the room & freezing your back in Winter. The masonary structure need not go right through the house, you can buy twin wall insulated fluepipes though they are not cheap. At least you can in the UK. Traditonal chimneys are expensive and inefficient, there are modern alternatives. The best thing you could do if you're bent on the primitive art of burning solid fuel is to get yourself a stove.
When I moved to central Virginia almost 20 years ago, I was surprised to see a large number of buildings with detached chimneys. These were standard looking brick chimneys but set away from the building in the three to six foot range. The flue from the furnace penetrated the wall horizontally and connected. If I can still find one maybe I can get a photo, most of these have been demolished in the meantime.
I asked the oldtimers why, and there was no answer, "we've always done it that way, doesn't everybody?" Perhaps, but I had not seen this in other areas.
I have a fireplace which I don't use. Because of combustion air going up the stack, you feel warm in front of it and cold in the rest of the house. YMMV.
In rural Louisiana, there was a saying by the local volunteer fire departments, "Don't worry. We always get there in time to save the foundation and chimney."
Steve
My insurance simply won't allow it. If the place burns down and a woodstove is involved, they pay $0.00 Obviously I don't have a wood stove.
Thanks for everyone's responses, but I will respond to this one. A woodburrning or pellet burning stove was my second choice. The house actually has a gas burning fireplace in it now with a metal flue but it seems extremely inefficient. I think a woodburning stove sitting further out into the room away from the wall might generate more heat into the room. Plus I can utilize the already existing flue to vent the exhaust. Thanks again everyone.
I used the money to buy a generator. Not as romantic, but helps keep me warm when the poewr is out.
We had a pretty good wood stove when we lived in Vermont. I would have used it a lot more, except that it had a "glass" front. The glass was easy to keep clean *unless* you relit the stove without cleaning it first. As long as the fire kept going it was fine. As the fire died it would smoke up the "glass". Another fire would bake it on making it one RPITA to get clean. The stove wasn't big enough to burn overnight, so...
Other than that it would drive you out of the house (requiring open windows - kinda counterproductive) if it was above 25F or so outside. At -10F it was great. The stove was located centrally in a pretty open-floorplan house so it did a really good job of heating.
OTOH, unless you have a really cheap source of wood, it's not going to save you anything. I figured I broke about even burning wood.
Get another insurance company.
Thats why we need insurance reform.
A fireplace is a lot of work but if done correctly and I repeat correctly they are efficient and the heat from a live fire is just way warmer than any baseboard or radiators. My rec room stays warm for a day after a good six hour fire. The wall holds and slowly releases the heat for hours. I have done repairs on lots of fireplaces done by phoney masons that are no more than holes in the wall. I now have an insert in mine so I use a lot less wood and it is very efficient with outside combustion air. Just get a real experianced mason with a track record.
Apart from the roof exit, you need to also think about the other end - where will all that weight be supported. If you are running a chimney from well above the roof, down through two floors, through the basement to the basement floor, that can easily be 35 feet of masonry, which is a lot of weight. Maybe too much to just sit on your concrete slab without some sort of load-spreading. You would want some engineering advice on that.
As many others have noted, a conventional open wood burning fireplace is generally a net heat loss. To make a net gain out of it, there are many design aspects that must be considered. Things that help are: outside air supply, glass doors that close, chimney inside house instead of on outside wall, engineered heat exchange (e.g., metal firebox inside the fireplace and and fan to circulate air). It can be done but it won't happen unless you really pay attention to that part. -- H
Heathcliff wrote in news:8d52288a-7e9a- snipped-for-privacy@g19g2000yqe.googlegroups.com:
A chimney, any chimney, sitting on a concrete slab?!
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