Strange chimney corbeling; chimney and stovepipe advice

[jimmyjabjames]

I'm going to try not to be long-winded about this, but I've had a year to lose sleep about it, and it looks like it's going to be 2025 before the work starts at this point:

• House built in 1973
• 51-year-old, original chimney, but the top section has been redone at least once or twice
• Chimney is an INSIDE one with a single flue/clay tile liner - "8 inch" (measures about 7 1/4" inside and some tiles are tighter with the sweeping brush than others - see photos)
• House still had an old Acorn Voyageur Stove in the basement in 2008 when we moved in, but idle.
• Chimney had been used for oil (forced air) furnace and oil (hot water boiler) from ? until 2009
• Our stove (2009) is a Drolet Baltic and I've got 6" single wall pipe with a 6" to 7" adaptor into the chimney, because the hole was 7" - as per two different WETT-Certified inspectors, we plugged the second hole with some concrete mix (DIY job)
• Since 2011, we've upgraded our insulation a lot and went from burning about 4 cord to 2 cord (3 face cords) and I often open the window to light it, but it drafts fine once it's going and I've only had it backdraft on me twice in 15 years
• In 2015 we put up walls and now the clearance to the pipe isn't code

Issue:

November 2023 I went up to sweep the chimney like I do annually and the brush wouldn't go down. I looked and the 2nd clay tile (12" length) was at a 45 degree angle (fell sideways). I was concerned, so I started calling masons/chimney sweeps. I actually talked to 3 people eventually, and it seems a few companies are no longer in business. One guy took 2 weeks to get back to me and he's busy enough with new construction (and near retirement) that he wasn't interested. Another guy (recommended by a friend) was off with an injury. The third guy is from a reputable company but it's been just over a year and it's too cold for masonry work again. Nobody really knows why it was corbeled this way, but I've been told that it could be a design to help drafting, or it's just for esthetic value.

• I needed to heat my home - we have a heat pump upstairs, but it's not enough. He figures the clay liner is cracked - there's definitely mortar missing, as the tiles never moved before. Last December, I went up and just straightened the piece and sat it on the one below it, but it's not mortared in place. I didn't get to sweep the chimney. He came in December 2023 and looked at it from the ground, checked it out inside the basement, and looked at photos I had.
• He gave me two quotes: one to take the chimney down to the attic floor and rebuild it at the proper 8x8 dimensions (clay flue, assuming it's okay), and one that includes a rigid ICC Exceliner (no insulation).

1. I asked him if I should just tear it down and install an insulated SS Class A chimney like a Selkirk or ICC Excel, but he didn't recommend it - he said it would make a huge mess in the house and my chimney is in good shape
2. I asked him about insulation and he said that's mainly a US thing, and it's not needed. I've also seen on the ICC website that it's NOT always needed, esp. an inside chimney.
3. ICC shows limited installation examples, but they show the liner inside the clay - I asked about this but he said he doesn't think it'll fit and they'd have to bust out the old clay liner to install the Exceliner

QUESTIONS:

So let's say I get this work done - new chimney top at proper size, rigid liner - how long before I need to have masonry work done on the chimney again? Should I just delete it and have a Class A installed?

He's going to sell me some double-walled stovepipe at my request. If I get a SS liner, how would he fill in the 1" void in the 7" hole? (7" hole has a metal retaining ring too). Is there a support you can get, like used for firestops/supports on ceilings with Class A chimneys (like a thimble)? Would he have to fill it with mortar?

I went up to sweep it again last month and the 2nd clay tile is even worse than last year. There's a larger gap to the top tile, and the top tile is CEMENTED into the crown (no bond break). I'm losing sleep because I'm concerned about a fire, although the creosote is minimal and it's drafting well. Since it's cold, and soon to snow, I asked if he can at least try to come over and install a liner if I need one and rebuild the brick later. Is that just a bunch of work that'll have to be redone?

Any help is appreciated! Thanks in advance.. more photos to come..

 

[jimmyjabjames]

More photos.. late 2023

also should mention that we had water issues with this chimney before and after the roof was done.. water was sitting where there was no cricket, but we ended up just extending the front roof up to the chimney with a little block under the shingles.. the chimney is only 2-3 inches from the peak.

The corbeling caused water to drip onto the roof trusses and box around the chimney and there's some rot/black wood. The most recent water infiltration was a few years ago and the water got behind my paint and bubbled it up.. i had to pop it to let the water out.. i coated the chimney with "Through the roof" silicone sealer and it's been fine since, but still needs to be rebuilt

 

[begreen]

The chimney needs an insulated liner. It is code unless the chimney has 2" clearance from combustibles at all points. It sounds like the clay liner should be broken out. Then there should be plenty of room for an installing a good quality, insulated, 6", stainless steel liner. This is a common practice.

I can also see why you have considered getting rid of the whole masonry chimney and replacing it with class A. I did that in our house. It's messy, but doable.

 

[jimmyjabjames]

Photos late 2024

The chimney brush is very far away from touching the top flue tile, but it's tight to the second.. I'm guessing the tiles are from different eras, or quality control was bad. The corbeled part in the attic is in worse shape than the rest of it and it obviously had several bricks replaced before we were here.

 

[jimmyjabjames]

The chimney needs an insulated liner. It is code unless the chimney has 2" clearance from combustibles at all points. It sounds like the clay liner should be broken out. Then there should be plenty of room for an installing a good quality, insulated, 6", stainless steel liner. This is a common practice.

I can also see why you have considered getting rid of the whole masonry chimney and replacing it with class A. I did that in our house. It's messy, but doable.

The chimney does have 2" clearance all around except at the roof penetration, which will be addressed with the new brick work.

 

[begreen]

Is it just the top tile in the corbelling that failed?
Did they run a camera all the way down to verify the other flue tiles and mortar joints are in good condition?

 

[jimmyjabjames]

Is it just the top tile in the corbelling that failed?
Did they run a camera all the way down to verify the other flue tiles and mortar joints are in good condition?

The second tile down is as far as I checked and no, he didn't even go up to the roof because he knew he wouldn't get to the work until 'who knows when'

 

[begreen]

The chimney flue should get a camera inspection to determine the state of the rest of the tiles.