Help make an old chimney functional and safe.

[themiddleman07]

Howdy hearth members! I've been snooping on this site now for about a month and noticed how helpful everyone is.

As an adult I'm brand new to burning wood. My dad burned wood for years when I was a kid, but too long ago for me to pay any attention to it.

Current situation: The house I bought this spring is about 35 years old. The house has an exterior chimney. It's masonry with a clay flue liner. The clay liner is exactly 6"x12" inside dimensions. The chimney is 18 feet long and comes down inside the basement. You can see in the pictures that the basement wall is built out underneath the chimney. This is all concrete construction, as well as the ceiling of this built out part.

I had a friend come over who's done some work of chimneys and he put a new masonry cap on my chimney. The old one was chipped off and the top of the chimney was flat with no flashing. So he helped me seal the top off.

On the inside the previous owner had a 9 inch piece of metalbestos stuffed into the whole you can see in the ceiling. He had rammed a 3 foot piece of single wall black 6" stove pipe through the metalbestos and up into the clay flue. When we pulled that out there was creosote packed between they flue and the stove pipe about 2 feet deep from where it was sticking up from the ceiling. That didn't seem safe.

We ended up buying two new 9 inch sections if metalbestos and joined them. We put those up into the hole in the concrete ceiling and butted them directly into the bottom of the clay flue. From the metalbestos we ran a black 6 inch stove pipe down to the stove. (Quadra-Fire 4300).

After a week of burning, we had a warm afternoon, in the 60's so I let my stove go totally out. That night it dropped into the 30s so I fired it up again. When I came back down to close it down a little, there was an almost steady stream of liquid creosote dripping down on the outside of the pipe hitting the stove and sizzling. This immediately worried me so I closed my stove way down and stayed up watching it until 2:30 am until I decided it was safe to go to bed.

What I am assuming happened, is that because the clay flue is 12 inches on one side it stuck out beyond the outside of my 8" (exterior), when I fired the stove before it could heat up the 18' clay flue, the smoke would go up and condense, then run back down and leak around the bottom of the clay liner and outside my stove pipe. I guess I'm not sure where to go from here. I tore it apart tonight and took pictures.

I have a flexible stainless steel liner quoted for around $350 that would create a near seamless connection to the of the chimney. How do I connect the stove to my 6x12 clay flue? Or is it important to run a liner? If so what kind?

I'd appreciate all the help I can get. Thanks!

 

[themiddleman07]

Here is a brighter picture.

 

[bholler]

ok that looks like fiber glass between that wood and the crock that is a bad clearance issue. Your liner is oversized for your stove allowing to much cooling which is exaggerated by an exterior uninsulated chimney and a poor connection at the bottom it sounds like it is time for an insulated liner and to start cutting to resolve the clearance issues at the bottom

 

[themiddleman07]

ok that looks like fiber glass between that wood and the crock that is a bad clearance issue. Your liner is oversized for your stove allowing to much cooling which is exaggerated by an exterior uninsulated chimney and a poor connection at the bottom it sounds like it is time for an insulated liner and to start cutting to resolve the clearance issues at the bottom

To be more specific, the ceiling is made of concrete and instead of a crock, its just a whole cut in the 5 inch think concrete ceiling. The wood you see is plywood bolted to the concrete. The metalbestos pipe was put into the hole in the concrete. But yes, I'd like to get that plywood out of there.

My stove recommends a 6 inch liner, but my clay flue is 6 inches inside. So could I use a 5 inch effectively, and still be able insulate it?

 

[bholler]

So could I use a 5 inch effectively, and still be able insulate it?

5" wont work very well 5.5" will work but you still wont have room for insulation ovalized 6" will work or what i would do if i were lining it would be to break out the old liners and put in 6" round.

And that plywood needs to go along with some of the framing as well I don't remember the required clearance right now but i am sure some one will chime in with it soon if not ill look it up when i get done with work and let you know

 

[Swedishchef]

Welcome to the forums!

As you can obviously see, the current setup doesn't seem safe. Personally, I'd try to either use an insulated liner (which won't fit in your clay flue) or put the stove elsewhere with a new chimney and block the current one off.

Clearance issues are certainly at hand. Chimneys that are insulated require 2 inch clearances from combustibles. Stovepipes require 14 inches (in Canada) of clearance.

I think you are quite lucky that the plywood never caught fire. Time to sit back and try to work something out. Other will chime in with other ideas shortly!

Andrew

 

[themiddleman07]

My local chimney sweep did inspect my clay flue and deemed it safe. Because of that, is it absolutely essential that I insulate my liner? Just trying to do this without spending too much money. The chimney sweep that came out and quoted me $2500 to get it up and going, using a combo of 6 inch metalbestos and insulated flex liner.

If I line the chimney with an stainless steel liner, how would I safely seal off the bottom of the chimney and connect that to my stove?

 

[bholler]

You would connect your stove pipe directly to the stainless And yes judging by what i see so far i am all but positive you do not have the required clearance between the outside of the masonry and any combustibles so yes you need to insulate it. And where was he going to use class a chimney?

 

[themiddleman07]

You would connect your stove pipe directly to the stainless And yes judging by what i see so far i am all but positive you do not have the required clearance between the outside of the masonry and any combustibles so yes you need to insulate it. And where was he going to use class a chimney?

I believe he was going to connect the SS liner to the Class A chimney at the very bottom of the clay liner, inserted into the hole in the ceiling. That would've take care of the required clearances, which are two inches using metalbestos.

 

[bholler]

And due to the fact that it is an exterior chimney even if it was not required for code and safety reasons i would still strongly recomend it because of the added preformance

 

[bholler]

I believe he was going to connect the SS liner to the Class A chimney at the very bottom of the clay liner, inserted into the hole in the ceiling. That would've take care of the required clearances, which are two inches using metalbestos.

Well that should work but most cass a chimneys want arspace not just clearance i doubt it would cause any problems but it technically is not right and if you are insulating the liner as long as you have 4" nominal masonry between the liner and the combustibles you are fine

 

[themiddleman07]

[/URL]

For reference this is the way it was hooked up for a week, before I noticed the creosote dripping, and quickly stopped using it. You can see the chimney pipe sticking down from where it was butted into the clay flue. I believe this is what the chimney sweep would have done, except for also connecting the chimney pieces to a stainless steal liner.

 

[themiddleman07]

Well that should work but most cass a chimneys want arspace not just clearance i doubt it would cause any problems but it technically is not right and if you are insulating the liner as long as you have 4" nominal masonry between the liner and the combustibles you are fine

So it looks like I will have to go with an oval shaped liner, or knock out my clay liner since the interior dimensions are 6"x12"? Yikes, this is a bigger deal than I thought. It's getting cold up here and was hoping for a quicker fix. However, I want to do it right.

 

[bholler]

We would break out the old liners but there is nothing wrong with ovalizing as long as it is done right and not smashed with a board and hammer.

 

[themiddleman07]

We would break out the old liners but there is nothing wrong with ovalizing as long as it is done right and not smashed with a board and hammer.

How would I go about breaking out the old liners? I would rather not break them out, since they're in great shape. But would be willing to if I for sure need to.

Also there are several companies that sell pre-ovaled liners, with smooth interiors. It looks to be around 500-600 before insulation for a 20 ft

 

[bholler]

We use a tile breaker and shovel the pieces out the bottom. If the smooth wall you are referring to is the double layer stuff i recommend against it either go with heavy wall or plain old light wall corrugated we always use heavy wall but light wall can hold up well to. I have never liked that double layer crap and have seen quite a few in pretty bad shape pretty quickly

 

[themiddleman07]

We use a tile breaker and shovel the pieces out the bottom. If the smooth wall you are referring to is the double layer stuff i recommend against it either go with heavy wall or plain old light wall corrugated we always use heavy wall but light wall can hold up well to. I have never liked that double layer crap and have seen quite a few in pretty bad shape pretty quickly

Good to know! I will double check it. It feels like I'm asking too many questions, but am appreciating the help. So, just to be clear. If I go with an insulated liner, I can run that down my chimney and hook my stove pipe directly to that? If I bring the insulated liner down far enough from the ceiling, will that take care of my clearance issues? (I assume I will still have to cut the white painted plywood back, or tear it out completely? The wood basement wall would be about 5-6 inches away (see the my latest picture).