recommendations for interior or exterior chimney?

The advantages to constructing inside the building envelope are numerous.


The flue will have less heat loss to the surroundings so you should ideally have less creosote buildup, stronger draft, and increased control over the appliance. Since the flue is "preheated" by the room air, you shouldn't have reversal problems or any another flue related problems that can sometimes go hand in hand with an exterior chimney, as long as you build the new chimney sufficiently tall.


Also, although minor in comparison, you may also get some additional heat storage value out of the increased thermal mass surrounding the flue gases.



All in all if you have the option, you want an internal chimney.

Others will be better informed than I am, but you may want to check out woodheat.org. They have a number of articals about flues.



http://www.woodheat.org

Are you absolutely sure you need to tear down that chimney? Why not build the addition right around it? Then you'll have your interior chimney.

Do the inside flue,you won't regret it.This summer I'm disconnecting my wall thimble into clay- lined exterior masonry chimney because I'm done fighting with it's heat robbing ability and frequently poor draft.I'll blank off the cap after removing the wall thimble, then rebuild the hearth I really want with double-wall to cathedral ceiling, then enough stainless above the roof to suck a seagull from a garbage truck.

Too bad as that is an attractive fireplace and chimney. The ivy can grow into the required gap between the house and brick though and actually topple it over time so don't let it get away from you.

The previous owner of my home had the same issue except a single story home and added on to the gable end of the house full height. The exterior masonry chimney is now my interior masonry chimney. The only trick is that the required clearances move from 1" to two inches but maybe elk can speak to that.

Chimneys are expensive to build and if you can keep this one up then that would be good.

In the end, I would like to follow Titan's lead and convert to a freestanding stove and metal chimney. My masonry chimney has some issues that would be very hard to fix without complete demolition or very expensive rennovation.

Others can chime in on your questions, just make sure you read about the "Evil Outside Chimney" from that woodheat.org site if you didn't come across it when there. http://www.woodheat.org/chimneys/evilchim.htm

jabram said:

...so the fireplace would be in the middle of the new living room.

Click to expand...

Sounds perfect to me!

Our old house had a woodstove with an exterior metalbestos chimney. The previous owner left us a list of "tweaks" to get the draw started and continued on the stove.

We moved the stove to a center location and reran the chimney through the inside of the house. We no longer have any problems with back draft and have virtually no creosote buildup. Also, the radiant heat from the flue heats the house on the way out.

We recommend an internal flue, if it will work with your house layout. Good Luck.

Are you planning on putting this new chimney on the one story addition? I have seen this done many times around here and they always have drafting problems. If you look in the manual for a wood unit, that is the "Not Recommended" chimney location. Not only does the wind not flow across the cap very well but sometimes the house itself makes a better chimney than the actual chimney. I have seen this not only with open faced units but also with a Quad 7100 or a HNG Northstar.

As a stone mason I can offer you my opinion from that perspective. Aside from putting all that nice thermal mass outside of your house rather than inside, you have weathering of the mortar joints to consider. A chimney, unlike a house is much more exposed to weathering ( especially if it's on the prevailing weather side of the house!) and some day will have to be repointed. If you're using weather-graded bricks or stone repointing work isn't too much of a problem although it is tedious and very costly. If you're using "cultured" stone grinding those joints out - which will have to be done to get the proper depth for quality repointing- can severely damage the thin veneer of coloring on the stone. The stone also cannot be cleaned vigorously after the pointing because of the thin veneer. I know you see a lot of this stuff going up outdoors and as a manufactured masonry unit it has it's own strength, but those guys making good money selling it and putting it up aren't going to talk you out of their payday. You've got to see these jobs once the mortar decays which depending on the quality of installation can be as little as 10 years and as many as 40. Though there aren't many masons left who know how to get you to that big number.

Just thought I would add one more thought on the same issue thats kind of funny. I often get calls directed to me of people complaining about smoking back or poor draft. This is usually how it goes.

Me: Is your house two stories or more?
Customer: Yes
Me: Is the fireplace chimney on a bumped out one-story section of the house?
Customer: ..... yes (how did he know that?)

..... its kind of scary how I can tell just from thier complaints that thier chimney is in such a location. I would definatly stay away from doing that at all costs.

If you are dead set on putting the fireplace there here are some recommendations.

You should get an EPA fireplace or stove with sealed doors, otherwise I for-see lots of smoking back.
Build the chase for the chimney as high as possible without it looking too goofy. The higher it is the better chance for a good draw.
Read up about requirements for HVAC return air and things like that, basically keep return air registers away from the fireplace and keep it balanced.
Keep the fresh air run short, this will allow the most possible air in.

There are some other factors with the rest of the house that will go into play. Best was for it to work good is for the house to be loose on the bottom and tight up top. That means the ceilings and top floor is sealed up good and maybe not quite so tight down in the lower level / basement. Can lights in the ceiling can act as alternate chimneys especially if they are the cheaper kind which are not sealed.

Also if you try to move the old fireplace, the chimney for it might not be available anymore. If any of it gets damaged trying to remove it you might be SOL.

You will also need to be careful what you burn, since the draft will probably not be the greatest it will be more sensitive to lower energy wood (like if it has too much moisture).

What about putting the stove where you currently have the TV unit drawn in? That would possibly let you run the stovepipe straight up and come out not to far from the peak of the roof, or possibly run it at an angle back towards the center of the room and come out about where the current chimney is?

You'd have to find a different place for the TV, (or better, throw the TV in the trash...) but it would be a better location for the stove in that it would get it out of the middle of the space, and put it in a more central position to send heat throughout the house instead of just one part of the room.

Gooserider

Here's a free web site to help you work out your floor plan: http://www.floorplanner.com/