Need help with ceiling clearances

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Bushmaster72

New Member
Oct 25, 2025
9
Pennsylvania
Hello,
This is my first post.
I’ve been burning coal in a Gibraltar insert for approximately 16 years.
We moved to a new ( old farm) house so I wanted to install a coal or wood burner in the basement.
I had a contractor install a masonry chimney. Its8” terracotta . He put a terracotta thimble through the masonry wall of the concrete.
I started investigating on how to connect a stove and then realized that the terra-cotta is only 7 inches from the bottom of the ceiling joist in the basement.
So my question is do I really have any options with this Chimney entrance if double wall pipe is only good for 8” ceiling clearance?
Is there any way to do a class A connection to the terracotta with a 90 degree bend before it goes to double wall? Or is there any option to use heat shield on the ceiling?

Thanks
[Hearth.com] Need help with ceiling clearances
 
That's too bad. Adapting class A pipe in this situation is not practical. A heat shield on 1" spacers off of the joists will help though not totally kosher. Consider using ICC Excel, Ultrablack, double-walled stovepipe. It has a 6" ceiling clearance. I'd also reroute the wires over this area.
 
Well according to the product specifications: I can indeed use this then! Thank u so much for pointing me in this direction. Next I need to figure out which part I need to adapt the 90 to the terracotta.

I’ll end up putting a fire shield with an air gap in the ceiling regardless as extra caution.
 

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Well according to the product specifications: I can indeed use this then! Thank u so much for pointing me in this direction. Next I need to figure out which part I need to adapt the 90 to the terracotta.

I’ll end up putting a fire shield with an air gap in the ceiling regardless as extra caution.
There also is not enough masonry between the crock and the sill plate. That needs to be 12" of masonry
 
That's too bad. Adapting class A pipe in this situation is not practical. A heat shield on 1" spacers off of the joists will help though not totally kosher. Consider using ICC Excel, Ultrablack, double-walled stovepipe. It has a 6" ceiling clearance. I'd also reroute the wires over this area.
Those wires will move. I’m in the middle of rewiring. The last homeowner did a bunch of sloppy electrical work and those are his wires.
 
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What can I do about the lack of 12” clearances within the masonary wall? Is it possible to ask him to drill a new hole lower and patch the existing entrance into the liner?
Honestly this project at this point is stressing me out. This is exactly why I usually do everything myself. Because anytime I hire somebody to do something they do it wrong. I’m about to just give up on the fireplace entirely
 
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maybe get a piece of metal roofing 3 feet wide. cut it 3 feet long set it on top of the clay pipe and screw it to the floor beams or clear the wires and screw it to the floor beams then screw the angle piece on
 
Using the ultra black double wall 90 takes care of the ceiling height. So thanks to begreen; that by theory is resolved.
The unresolved issue is that the pass through the masonry wall itself is far less than 12” from the combustible sill plate. ( it’s more like 6”) I can think of only 2 ways to resolve that. Option 1 is move the crock lower which means that somehow the original penetration in the flu needs to be sealed, option 2 is to replace the crock with a class a thimble which also seems like quite the ontaking of both labor and materials. Those thimbles are about $800 to pass through a wall of this thickness.
I guess the third option is to just run it as is knowing that the 12” distance is overkill as is most anything that is mandated by code. But is 6” way under kill? That’s the fear. That and I’m sure if I had it inspected for my homeowners policy that this situation would be identified by the inspector.
I was ready to go purchase a stove this week but now I’m feeling grim about this project and don’t see it being completed this season.
I’m going to have a conversation with the contractor tomorrow. Clearly he doesn’t understand clearances.
 
Using the ultra black double wall 90 takes care of the ceiling height. So thanks to begreen; that by theory is resolved.
The unresolved issue is that the pass through the masonry wall itself is far less than 12” from the combustible sill plate. ( it’s more like 6”) I can think of only 2 ways to resolve that. Option 1 is move the crock lower which means that somehow the original penetration in the flu needs to be sealed, option 2 is to replace the crock with a class a thimble which also seems like quite the ontaking of both labor and materials. Those thimbles are about $800 to pass through a wall of this thickness.
I guess the third option is to just run it as is knowing that the 12” distance is overkill as is most anything that is mandated by code. But is 6” way under kill? That’s the fear. That and I’m sure if I had it inspected for my homeowners policy that this situation would be identified by the inspector.
I was ready to go purchase a stove this week but now I’m feeling grim about this project and don’t see it being completed this season.
I’m going to have a conversation with the contractor tomorrow. Clearly he doesn’t understand clearances.
what amazes me is you saw where he was cutting the hole to close to the wood and didnt say anything
 
I’m going to tell him tomorrow that I’m not going to bother using the chimney in its current state. At this point I’m throwing in the towel. I’m having spray foam installed next week and will have heat pumps installed as well. My dream of a wood fire at this point is over and has only become a nightmare that I need to end
 
Darn. What a headache.. do I have any options for that? Have him remove the crock and install a proper pass through?
Yes a piece of class a through the wall is probably the easiest option
 
Using the ultra black double wall 90 takes care of the ceiling height. So thanks to begreen; that by theory is resolved.
The unresolved issue is that the pass through the masonry wall itself is far less than 12” from the combustible sill plate. ( it’s more like 6”) I can think of only 2 ways to resolve that. Option 1 is move the crock lower which means that somehow the original penetration in the flu needs to be sealed, option 2 is to replace the crock with a class a thimble which also seems like quite the ontaking of both labor and materials. Those thimbles are about $800 to pass through a wall of this thickness.
I guess the third option is to just run it as is knowing that the 12” distance is overkill as is most anything that is mandated by code. But is 6” way under kill? That’s the fear. That and I’m sure if I had it inspected for my homeowners policy that this situation would be identified by the inspector.
I was ready to go purchase a stove this week but now I’m feeling grim about this project and don’t see it being completed this season.
I’m going to have a conversation with the contractor tomorrow. Clearly he doesn’t understand clearances.
If he can just lower the crock that would be the best solution
 
It’s 8” you said.
I’m going to tell him tomorrow that I’m not going to bother using the chimney in its current state. At this point I’m throwing in the towel. I’m having spray foam installed next week and will have heat pumps installed as well. My dream of a wood fire at this point is over and has only become a nightmare that I need to end
Insulation and heatpump are great additions. You will be pleased with those. Anyone working on a solid fuel venting system must know the code. I would ask for a refund or for it to be done correctly.

What’s the price of coal and wood and electricity for you?