Free standing stove install questions

[brian89gp]

I am hoping to install a free standing stove on my 3rd floor/converted attic space. My question is mainly how to tie into the masonry chimney. It is an old house where the chimney flue is built into the 3 brick wide brick walls (back when they burned coal) and it is an open flue all the way from the basement to the top cap. How do I run the stove flue into the brick chimney and then run a stainless liner up to the cap? I don't think I could do the normal T method in the chimney with a cleanout below because the entry point into the chimney is 30' off of the ground and it is open chimney flue underneigth of it. I am rebuilding the chimney from below the entry point of the flue on up so if I need to add support for the liner I will be able to.

Also, what is the slope required on a horizontal run of pipe? The stove is going to sit 3-4 ft away from the chimney and I am going to need a rear exit stove and all horizontal to the brick chimney. I have just under 3' of vertical brick face on the inside of the chimney to work with as it is on an exterior wall and the roof intersects the chimney at 3' above floor level. Is this even possible/advisable? I found several stoves that had the rear exit centerpoint at 24-25".

 

[Slow1]

I wonder if with that horizontal run you will affect your draft in a bad way - being right under the roof I am assuming you don't have a tremendous amount of rise in the plans to begin with so that may challenge things as well. A straight shot up through the roof (i.e. new chimney) may be the best thing for you to get a good draft and may make your long term cleaning easier too. Granted it is another roof penetration which has its own challenges, but that is manageable.

 

[brian89gp]

There will be about 12-15' vertical chimney rise, old victorian house with good ole 12/12 roof creates the need for some very tall chimneys. I would be restricted from adding a new chimney by historic preservation.

 

[Backwoods Savage]

1/4" rise per foot of horizontal is minimum. I suggest going 1/2" rise per foot. We've done both and the 1/2" rise does much better.

I wonder with the installation on the 3rd level, how tall will that chimney be? The entry to the chimney is 30' up so if you need 15' plus (need more with bends in the pipe), how tall will that chimney need to be above the roof line? Will you be able to handle that?

 

[brian89gp]

There will be whatever horizontal length, the 90* bend, then between 12' and 15' of straight vertical. The exposed chimney height is around the 12-15' mark.

With a 12/12 roof, using geometry of a right angle triangle with two 45*'s, 10' horizontal from the nearest roof structure will also be 10' tall above the roofline. So 12' minimum (2' above the 10'). The roof ridge is about 16' above the point where the chimney interects the roofline so the original chimney might have been taller then the 12' and the historic people may dictate that it has to be closer to original 16' then the 12' minimum required by fire code.

If I pay someone to do the brickwork I'll talk them into using their scaffolding and install the liner and cap before they take it down. If I do the brickwork myself I will already be up there.

If it helps any, attached is a picture from the 1940's that has at least most of the original chimney in it. It is almost off the frame on the left side. For reference, the height of the ridge of the dormer with the window is 9' above the roof penetration of the chimney

 

[brian89gp]

PS. Bottom up chimney cleaning for during the season cleaning and either I rent a boom lift once a year for top down or pay a sweep. The rear chimney is just as tall though it is closer to the ridge so less is exposed.

I am planning on having another SS flex flue comming from the 1st floor up through this same chimney. Heating 3800sq/ft of old house takes a lot of wood and fireplaces.

 

[Backwoods Savage]

Sounds good.

 

[brian89gp]

How do I go from the class A horizontal pipe to the SS flex for the vertical section though? Or do I install class A into the vertical section of the chimney as the chimney is built? And do I do a simple 90* class A bend to go from horizontal to vertical?

ID of the chimney chase will be 8.375 x 24.375 so a 8" OD class A pipe would be a very snug fit.

 

[begreen]

Why class A instead of double (or single) wall connector pipe? This sounds like an insulated stainless liner will be used in the chimney, not class A. Would it be possible to install the liner tee with a short length of pipe attached to the bottom, then create another hole below the thimble and attach an elbow to that short pipe, then cap it for a cleanout? If you can post some pictures of the interior where this stove is going we may be able to offer better options. So far I don't see any need for class A pipe.