Chimney removal advice – GreenBuildingAdvisor

I have a chimney that runs through the middle of my house. The chimney above the roofline is not only letting water into my house – even after adding caps – but the mortar is so recessed that it’s not structurally sound.

It runs into my attic, behind drywall for floors 2 and 1, and then is exposed and filled in with bricks in my unfinished basement. I’m getting ready to replace my gas water heater which vents out the chimney, so it’s about to be non-functional (but a structural liability). Seems silly to repair the exterior portion at this point, when it’s a thermal bridge and air leakage source, and sign myself or the next homeowner up for continued tuckpointing down the road.

A point of confusion for me is that the chimney, at least what I can see 4 feet up from the bottom of the slab, is completely full of….various things. When I removed a cap to look inside, a fossilized bird and a bunch of debris came out. It’s been rewetted multiple times through the water intrusion.

So question – Good idea to remove the section above my roof and in the attic, and bring it down to the level of my ceiling and cap it off / seal it and insulate it there?

Or could this somehow make the portion of it running through my house less structurally sound, because it benefited from the framed around it at the ceiling and roof? Thanks in advance.

Climate Zone – 4A