Attention Retro-Geniuses. Help Needed

[rwoods]

My stove hasn’t been drafting very well lately so I thought it was time to get the chimney swept. I scheduled it for Monday. It’s been raining all day so I decided to do the stove pipe myself and open up the access for the sweep. Sure didn’t like what I found – flue tile busted from cleanout to the first floor. Cleanout cover shows evidence of a nice little chimney fire.

My stove flue tile extends at least another 30 feet up my hollow masonry (concrete block, brick veneer) chimney. It runs in the corner. In the center is my fireplace flue which is much larger, but also tile. My stove flue tile is not supported at the first floor, it simply passes through. I intend to replace/re-line the flue with a SS flue.

My questions: Do I attempt to replace the broken tiles? Or do I build some other support for it? Or do I attempt to dismantle (i.e. demolish) it? If I should demolish it, what is the best approach so I won’t endanger my chimney flue which has a huge tile throat?

Thanks, Ron

 

[dave_dj1]

I'm not sure about the codes in TN but that looks like the most UNSAFE thing I have ever seen!
Is that a clay tile in the corner of a concrete basement with no protection around it?
If it is I would consider using 4" block and boxing it in, if it goes through the first floor with no protection I would NOT use it!
Clay tiles are meant to be inside of masonry chimney's and not as a stand alone product. I'm surprised you haven't burned your house down already.
Please, do us a favor and don't burn until you get things done properly!
Even with a SS liner I wouldn't burn that way.
dave

 

[rwoods]

It is enclosed in a poured concrete walled cavity - 8" thick on interior sides and 15" thick on exterior. There are two access points that I took the pictures through. These are covered with metal. First floor up is a 8" concrete block cavity. Ron

 

[chucker]

!! PROBABLY GET HOLLARED AT FOR THIS!! but that is just plain "dumbass" reason to be had for a midnite fire !! !! PLEASE, CALL THE FIRE DEPARTMENT NOW!!..... ITS 911 OR NINE ELEVEN .... good luck??

 

[rwoods]

I assume you were typing your post as I was typing mine. It is completely enclosed except when the two metal access panels are removed. Ron

 

[Steve NW WI]

If I were you, I'd get that clay tile out of there, and run an insulated stainless chimney (not just a liner) up through that space.

I hate clay and block chimney, and clay without the block directly surrounding it is gonna result in problems like you're having. My tile and block chimney is getting retired this summer for stainless.

 

[rwoods]

Insulated chimney is what I was thinking but I'm not sure of the sizing - the tile is roughly 9" square outside. I am hoping that someone would know an easy way to bust up the old tile without endangering my fireplace flue and without having to shimmy down the chimney. Ron

 

[rwoods]

A 7" ID (9" OD) insulated chimney will fit through existing hole in concrete floor but I will need to confirm that 7" ID is big enough for my stove which uses a 6" pipe. Ron

 

[Steve NW WI]

Ron, a 6" outlet normally runs 6" all the way out, but if 7" is a better fit in your install, there's no harm in going a little bigger, and if you install a bigger stove down the road with a 7" collar, you're ready for it.

 

[stihl waters]

A 7" ID (9" OD) insulated chimney will fit through existing hole in concrete floor but I will need to confirm that 7" ID is big enough for my stove which uses a 6" pipe. Ron

Exactly what you need, you'll be glad you made the switch.

 

[rwoods]

Thanks, Guys. I hope the sweep and I can figure an easy way to take down 30 feet of tile from the top. The other 12 feet will be a piece of cake as it is busted all to heck and is one story below the fireplace. Ron

 

[rwoods]

Thanks, I have been looking at that site off and on this evening. To use a liner I'll have to rebuild about 12 feet of the flue from the bottom up in order to support the rest and that is assuming that the rest isn't broken as well. I believe replacement with an insulated chimney is the safest course. Ron

 

[Steve NW WI]

Del, the problem with your idea, is that the clay tile is designed to be supported by a concrete block outer shell and isn't stable the way it is in Ron's. Lining it would be like changing oil in a car with a rod knocking. It might help for a little bit, but catastrophe is still a coming.

 

[promac850]

Yeah, that needs to be redone pronto... SS insulated the whole way from a conceivable place. Ours starts at the bottom of the former fuel oil furnace chimney, and runs to the top...

We have an 8" liner, and run a 6" black painted pipe from the stove to the chimney. It was clean as can be when we had it swept... the pipe leading to the chimney had more deposits of ash and crap than the entire SS flue did.

How many BTU's is your stove rated at? How about brand and year of manufacture, and is it a newer high efficiency stove or an older not so efficient stove?



Our Lopi is something like 20,000 BTU's, and it is the 'Answer' high efficiency stove. Good for keeping the house at comfy temps until it gets to about 50 degrees out, then it's gotta be shut off. We have about a 2200 sq. ft. house, IIRC.


Your tile chimney is way past its prime... that grime oozing out is creosote... and if that's outside, it'll certainly have some inside. Major fire hazard, and the fact that you've already had a chimney fire event in there, it an imminent danger and could burn your house down the next time you light the stove.

Please get that done the right way, soon... insulated SS liner... don't light the stove until you get a new chimney in place... it isn't worth it.

 

[dave_dj1]

I wish you could explain to me how/why the concrete cavity is/was built. I have never seen this type of design. Is this something you did or is it standard procedure down your way? I'm not bashing but I am concerned for your safety and your families safety. I just don't see how this could possibly safe in any way except for maybe if you do the insulated pipe all the way up.
Good luck,
dave

 

[laynes69]

Maybe post more pictures of your setup? I also don't understand. Those pictures you posted of the terra-cotta tiles look like there's nothing around them.

 

[cantoo]

My old clay flue chimney was even worse than yours. It hadn't been used in several years when I tore it down but I suspect it was pretty bad when we were using it. It was clay flue and poured concrete against them and then brick exterior. No chimny cap on the flue. It appeared that the clay expanded from heat and cracked which allowed water in behind the clay which then froze and further cracked the flue. I now have a complete insulated stainless chimney straight up from my stove. After seeing mine as I tore it down I would recommend anyone with clay to replace it immediately regardly of what it looks like and how old it is. I just don't think they are a safe method of venting. I don't really care how good they look today, at some point it will not be okay and realization point might be during a fire. I have 2 brand new unused clay flue ( Dad built our house, chimney is real wide and has 3 separate flue chimneys in it) and after seeing the damaged one I didn't even consider using the others.

 

[rwoods]

I wish you could explain to me how/why the concrete cavity is/was built. I have never seen this type of design. Is this something you did or is it standard procedure down your way? I'm not bashing but I am concerned for your safety and your families safety. I just don't see how this could possibly safe in any way except for maybe if you do the insulated pipe all the way up.
Good luck,
dave

Maybe post more pictures of your setup? I also don't understand. Those pictures you posted of the terra-cotta tiles look like there's nothing around them.

Dave and laynes69, I appreciate your concerns. Maybe I can relieve them a little. My home is custom built. Due to the terrain the basement is 12’ below the first floor. As designed the house was to have two back to back “Rumford” fireplaces; one inside as part of the living room and one outside as a part of the adjoining porch. The “cavity” is actually the extended foundation for these fireplaces. The back wall is 15” thick poured concrete with rebar, the front wall (interior to basement) is 8” thick poured concrete with rebar and IIRCC the side walls are 15” thick poured concrete towards the back wall and 8” thick poured concrete towards the interior wall, all with rebar. The “cavity” has a concrete “floor” (actually the footing pad) and it has a “ceiling” of 6” thick poured concrete with rebar. This “ceiling” is the pad upon which the chimney is constructed. As previously stated the chimney is 8” concrete block faced with brick. A hole was left in the chimney pad to thread a 9” square flue tile for a wood stove in the basement. The interior wall of the chimney foundation was poured with two small access points; one for the stove pipe and one for a clean out. Unfortunately, my mason was too big to fit through the top of the cavity before the chimney pad was poured much less through either of the openings so the contractor constructed the stove flue from the foundation up through the chimney pad. The mason constructed the stove flue from the chimney pad as he built the chimney. He enclosed the flue in masonry as well as the fireplace flue (we chose not to build the outside fireplace and there is left over space on one side of the fireplace flue). I don’t recall whether he used chimney blocks or bricks but I believe he used bricks to encase each flue. I remember there were several discussions about clearances between the clay flue liner and the encasement as the fireplace manufacturer called for something different than the mason was accustom to building. I don’t recall who prevailed but an agreed construction was reached. Other than the contractor, I don’t think any knowledgable person was aware of the manner in which the flue was constructed below the chimney pad.

The first winter after construction I purchased a wood stove for the basement. My dealer immediately noticed the lack of complete side support for the flue and he installed the strapping you see in the pictures. He also installed the SS cover over the bottom opening of the flue. Other than the creosote from the flue, there are no combustibles within the cavity and it is difficult to conceive the amount of fuel it would take to heat this solid structure to a temperature that would cause the structure to fail or cause the combustion of an outside combustible, except creosote within the flue above the structure.

From a safety perspective, I am concerned about a fire resulting from a structural collapse due to the failures shown in my pictures (other than friction and the cement sealing the tile that passes through the chimney pad, the vertical load of the flue is carried by these compromised flue tiles) – the accumulated creosote from the first floor up could blaze away in a clay tile rubble pile created within the block/brick encasement if the flue should collapse. I am also concerned about a fire started by an ordinary chimney fire within the flue above the concrete structure.

I now have little confidence in the continued integrity of clay flue liners (especially after viewing my unsupported portion) and as indicated above I don’t have the same containment confidence in masonry joints as poured concrete with rebar. Thus I want to go SS to the sky. All of which led to my questions about removal of the encased flue so it can be replaced with an insulated SS chimney or providing support for it so it can be relined in SS. There is no way I am going to leave the bottom portion of the flue as is and simply line it with SS. Unfortunately, no one has addressed these questions.

Ron

 

[cantoo]

Ron, hard to tell from your pics but it doesn't look like a SS insulated chimney will fit inside your clay flue and now after your explanation it doesn't appear as if you need the SS insulated pipe, a SS liner should be fine. Of course this doesn't mean a whole lot sitting here at my desk in Ontario, codes are different everywhere. I would call your building inspector and have him come take a look and give you suggestions as to your options, if he isn't the qualified person then I guess your next bet is the chimney sweep. I say the chimney sweep because around here they have to be licenced and most are also chimney installers so they know what they are doing. As for support, I would be surprised if the upper flues could fall out on their own. When I removed mine I had to smash them into little pieces to get them out. I think bust out the lower unsupported ones and the uppers will stay put. And I agree with you on the clay flues, they are unsafe I would never considering using them ever again.

 

[rwoods]

Thanks, Cantoo. I'm trying not to write a book but my structural concern relates to the clearance issue I mentioned. If I recall correctly, the mason's practice was to put mortar between the encasement and the flue tile whereas the manufacturer of the fireplace specified a gap and actually marketed some sort of sleeve so the flue could move independent of the encasement. I think the manufacturer won out but I don't remember as too many years have past. Anyway, if there is a gap then there is no vertical support other than the busted tile, the masonry seal at the pad and the sealer at the copper rain cap.

Subject to the sweep's judgment, my plan is for him to inspect the upper tiles and if found sound, then remove the busted tiles, put in some new vertical support in their place and reline the flue. If there is an easy way to remove the tiles, I will and I will put in a Class A insulated SS chimney in their place.

Other than old nuts like me, no one builds masonry wood burning chimneys around here any more much less ones with clay liners; they just built a stud cavity and run a SS chimney in it, or if it is gas fired, out the side of it.

Thanks again, Ron