D. Bumpus

Thank you for the ideas! I like the idea of using the Roxul and adding a good bit of insulation, then figuring out the way to cover it. I think if I go with too much the chimney will really look gigantic against the house, unless I cover it up with siding like the rest of the house (Planning on upgrading the siding someday).

I like the sunroom idea, will be a little difficult but it would help recover a lot of the heat as you mentioned. Also thinking that a small greenhouse on that side would do the same, the house is not set up well to get any passive solar currently.

With the Roxul ideas I'm thinking I could cover it up and seal it well, and if I want to sell or rent I can take it back off if the chimney stonework is really a good selling point. Though I'd rather leave it on and cover with more stonework or something very nice looking. I like that with the Roxul (or fiberglass) it wouldn't Have to be permanent, but probably would.

I appreciate knowing that others (ie. Poland) have the same thoughts for old chimneys.

The chimney is very large and could never get hot enough on the outside to be a danger to foam board, but I understand the concern. Here are pictures from when I bought the house.

Eventually I'd like to build a rocket mass heater, but I'll probably be doing that in our final house when we build ourselves. Currently I'm living in a home I bought to make into a rental, but we're living here for now. The fireplace/chimney is a pretty nice focal point inside and outside the house. It looks original to the 1940's house and is built of round fieldstone gathered from the property itself. I love the look of it.. but since it is on the outside wall it just seriously leaks heat out.

I'm planning on putting in an insert to make it much more efficient at heating the house, but I fear that I'll be wasting so much heat as it conducts out through all the stonework, instead of letting me use that stone as thermal mass working for the house.

My thoughts have been to put Styrofoam board (2") against the stone on the outside, use spray foam or some sort of vermiculte to dump in between all the gaps (the stones are not really even at all) Then do a stone facade on the outside of the foam board (I'd have to make sure to drill in wires/supports that stick out through the foam to help hold up the facade i think).

I hate to cover up the original stone on the outside (would still be visible on the inside) but I'm not sure how else to make this fireplace work for us instead of against us.
Any thoughts would be appreciated.

I am thinking of galv flue pipe like i installed for my furnace. Following the link posted above gives some good discussion on galvanized pipe. I would still use it in the bench but probably try and get or make something better for the riser.

Around here stove pipe (single wall) is around $7 for a 5 foot section. I can't think of anything that can stand the heat that would be cheaper. You might be able to form your rocket stove bench a little at a time and pull out a pipe you used as a form in the cob then use it for the next section, but I'd be worried about it caving in over time. You could form with brick in the bench but I don't think that would be cheaper.

Awesome build!  I really appreciate you documenting the whole thing.  I hope to do something similar in the future (smaller though). 

How did you deal with getting the roofing rubber?  I have been thinking about the possibility of using billboard tarps.  "Tough, Tear Resistant, 15-17 mil thick, Waterproof, 13-16 oz per sq. yd, Anti-UV, Vinyl, Anti-Mildew, 3-Ply Material"

I definitely think you should go to a big gun shop and try out how the weapon feels and if possible rent it and shoot it some.  I bought a bantam 20 gauge shotgun for my wife (home defense) since she could hardly pick up my 12 gauge.  I thought about the super bantam but I wanted one that was compatible with the other mossberg 500 parts (which my 12 gauge is)  Apparently a lot of the parts of the super bantam are not interchangeable with the normal 500 parts, the bantam parts are.

The bantam stock is very adjustable, and since it is a youth shotgun you can mail them a letter (comes with the gun) and they'll send you a full size stock.  Basically a gun you can grow with.  Obviously in your case you don't need that, but it could be a good thing to have if you ever sell or give away the gun to someone that has a different build than yourself.

BTW my wife is about 5'2 for comparison.

I want to do something similar and have concerns on drafting.  Did you add a bypass to start the stove without the majority of the thermal mass?  Is the chimney vented out a basement window or did you do a chase all the way up to the roofline?  If a chase.. did you do so inside or outside the house (Thinking a heated chase would keep a good draft going.

Would you mind posting some pictures of your fan setup?  Thanks!

Sounds like a good plan to build the Spa building to live in while you get the rest done, will be small and easier to get done.  The water will actually be a great thermal mass too, better than stone or cob per volume.