brick chimney

[rattlem'up]

Will be reroofing my house soon and was thinkin about tearing down the chimney, framing it in, cutting the furnace vent down and installing a vent over the top of it. Now i saw that there is a steel or cast iron liner inside the chimney. any idea how far that would go down? Would it just go down to the roof line and stop? Just wondering if any of you roofers have ran into this before and what you did about it. I would leave the chimney up but the mortor is shrunk and falling out so it doesn't look the best. thanks for any info

[icechipper]

Is there a cleanout in the basement for it? Mine has a cleanout and also the old vent holes and can tell it has a one inch or so liner that appears to be block of some sort. Hope this helps.

[CFRay]

Many masonry chimneys were originally built with a fired clay flue liner. Many were further retrofitted with a stainless steel double wall pipe that goes from the basement furnace to the chimney top inside the masonry chimney. These were installed from the roof down to the basement and then connected to the furnace. I suspect that is what you see. I do not know of a cast iron pipe chimney system.

If the chimney you describe is alongside the house you could tear it down, frame it up out of wood and replace the steel chimney vent inside it. If the chimney is just out the roof you'd be able to alter the steel pipe to fit inside your planned frame chimney top.

[Surface Tension]

I'm thinking you have a flexible stainless liner and what looks like cast iron is part of the termination cap. That cap holds the liner up. Please verify that for us.

If the above is the case then normally you'd clean out the old loose mortar and repoint the brick. At the same time you'll add new flashing. Depending on the age of the home determines what type of mortar you'll use.

[rattlem'up]

The chimney is in the middle of the roof. I'll look tonight with a flash light and see if i can tell how far down it might go. The house was built in 1965. The actual chimney isnt neccessary for the furnace to function. There is a 6" round vent comming up from the furnace out the chimney. That is why i'd like to tear the chimney down past the roof line and throw a frost proof vent up over the chimney pipe. But if that liner runs all the way down it might be too much of a hassle to screw with it and easier to fill in the mortar.

[fishermatt]

I put a stainless liner in my cement flue chimney, may or may not be the same as yours. It has a T on the bottom that connects (by screws and high temp cement) to a double wall pipe that comes out of a hole in the chimney, through the wall and goes to my wood stove. It would be similar for a furnace. From in the house, If you remove the pipe where it goes into the chimney, you should be able to see where the liner connects. You would have to remove that T at the bottom so you can remove the liner out the top.

[CFRay]

If its not in use then you could remove it and build the roof over it. Chimney flashings are a leak source. The mortar is 40 years old, taken many freeze/thaw cycles, could be rotten and not agreeable to a tuckpoint effort. If you're not using it, get rid of it.

[rattlem'up]

I looked with a flash light in the chimney from the roof and the liners inside look like they are in 4' incraments.