Chimney—Attaching Pipe—Conundrum

I took off the chimney. And realized I may have another issue

. So I’m here again to ask for wisdom.

I plan to put a brick veneer on the outside of the stucco. Therefore, I added fire blanket to the chimney and covered with stucco. The stucco went over the top of the chimney blocks and now I have an approx 2 inch lip. See the pictures.

Do I:

1.) Cut the stucco off the top blocks somehow? And then add another row of fire brick with the cut outs for the chimney pipe and use high temp mortar to put it in place and remove any places where water may get in and freeze?
2.) Leave the stucco as is and build up a “cap” with high temp mortar?
4.) Leave the stucco as is and build up a “cap” with stucco?
5.) Cut the stucco off the top blocks somehow? And then and build up a “cap” with high temp mortar?
6.) Cut the stucco off the top blocks somehow? And then build up a “cap” with stucco?

Pictures from above are so worth it. Thank you for attaching them.

Number 2 would be my choice. Leave your stucco alone, as it is not hurting anything. (It is a bit unusual, but I understand your thought process.)

I would place your vent so it is based about 2 inches above the top of the stucco. So I’d recommend this:

  • Protect the hearth with a drop cloth.
  • Build a high-temp mortar base for your crown, to the level of the stucco (you can use it as a form), and allow it to cure for a few hours.
  • Once it is firm, build a high-temp mortar crown, with the top about 2 inches above the mortar. Once it has set, but is still workable, use your trowel to slope it out just a little from center to edges, and do as you’d like for the sides (if you’re planning to apply veneer to the sides of the chimney crown, you might want a more regular surface there, or you might just want to let it rise as it is).
  • After it has had a chance to cure for 48 hours, you can apply high-heat adhesive silicone to attach your vent pipe, and clear silicone sealant to the seam between the crown and the stucco. You definitely want to waterproof that area.

You’re really getting close to done here! And the knowledge you’re gaining about what goes into a build like this is priceless…really! Let me know how it goes, of course.

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How’s this look Matt? I had to add about 4 inches of high temp mortar when everything was said and done. Two to make it even with the stucco and two to get a slope.

I went a little crazy with the high temp silicone, but I didn’t want the chimney to come off or water to get in. And no one is going to see that part.

The bricks on top of the chimney piece are just there for some staying power while the silicone sets.

You have a strong, waterproofed chimney there, and I think it looks great!

I think you’re ready for veneer now, which will be your home stretch. Good job!

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