chimney is too small

[blfaulk]

Hi.

I have a 1940's chimney made for a wood stove. That is, there's no fireplace. The chimney is rectangular and runs from the basement floor, through the second floor and to the highest point of the roof. The inside dimensions are very small (4.5 by 8). A chimney sweep told me that he could "ovalize" a 5 inch insert and "make it work". I'm not comfortable with this idea, since I plan to get a wood stove with a 6 inch pipe. Would it be possible to remove the chimney and put in a metal "class A" chimney? If so, how should I go about removing the chimney? The chimney passes through the center of an upstairs bedroom. There are several thimbles in the chimney; one in the basement, two on the main floor, and one on the second floor (amazing, right?). All of the metal chimneys I've read about need a 2 inch clearance from combustibles. Can I build a studded wall around the metal chimney in the second floor bedroom, as long as I allow the required clearance?

Thanks!
Bryan

 

[begreen]

Removing the chimney is messy, but goes quickly once you are set up for it. We did it with a full chimney and a full fireplace + chimney. Start at the top and work your way down. All you need is a flat chisel and a hammer to work at the mortar joints. Wear a dust mask and we found it really helps to have an exhaust fan running in the room. I also tented off the area with ceiling to floor plastic, creating a tunnel between the chimney and the nearest window where I could dump out the bricks. If you can have two people, one chipping out the old bricks and one passing them on and out the window you can proceed very quickly, especially if the chimney is unlined and this is old mortar.

Once the old chimney is out you will need to patch the hole in the roof. Then cut a new, oval hole in the patch for the metal chimney. Yes you can frame to within 2" of the class A pipe in order to chase it through the bedroom. The chase ID for 6" class A will probably need to be 12" x 12".

Is the intent to install the new wood stove on the first floor? If so, you will need to frame for a ceiling support which will probably be easiest from the bedroom. Predrill the framing pieces and screw them in place in order to not disturb the 1st floor ceiling.

 

[cmonSTART]

Does this chimney have a clay liner? Is it not possible to break and remove it to make room for a larger stainless liner?

 

[Backwoods Savage]

Welcome to the forum blfaulk.

We too have torn down a chimney and it went faster than I expected and was not that difficult. BeGreen is right about the mask and tenting off the area!

 

[blfaulk]

Thanks for the super fast response. The chimney has no liner. Now I'm a bit worried about the roof. I believe it's the original "tin" roof. Anyone have some advice on how to repair the roof once I remove the chimney?

 

[RSNovi]

The area of your rectangle chimney is larger then a 6" round chimney. Maybe it would work if you can connect your stove to it.

 

[cmonSTART]

Thanks for the super fast response. The chimney has no liner. Now I'm a bit worried about the roof. I believe it's the original "tin" roof. Anyone have some advice on how to repair the roof once I remove the chimney?

I see. Tearing it down really won't be that hard. A good demolition hammer rented for a day can really speed things along, as will helpers to run buckets of rubble out of the house.

Regarding the roof, Class A manufacturers (Dura Tech, etc.) make special flashing for metal roofs which will probably work to keep rain out.

 

[Wood Heat Stoves]

Typically you would take a flashing for your class A system to a sheet metal shop and have them attach a lead apron to it that would conform to the metal roof to seal.

 

[Danno77]

The area of your rectangle chimney is larger then a 6" round chimney. Maybe it would work if you can connect your stove to it.

Unlined brick chimney is probably a bad idea.