Chimney Termination Question....

[kevaleva]

I had a prefab fireplace and am in the process of switching to a pellet stove. I am running a 4" MFlex liner down my existing chimney. However, when I climbed on the roof today to survey everything, I was scratching my head trying to figure out how I terminate a square chimney cap on top of a round chimney. The outside diameter of the chimney pipe is 12-1/2", with an 8" pipe inside of that. The square termination cap that came with the MFlex kit is 13" x 13".

Do I need to take it to a shop and have someone bend it so it fits around the pipe and rests on top? If I do that though, I'm left with only about a quarter inch of material on the sides. Please help me, I'm a newbie to all this. Pictures are attached of the existing chimney cap and the new one that came with my kit.

P.S. I know I need a new chimney chase cover...I'll order that soon and put that on before I figure out this chimney cap problem.

 

[DAKSY]

I would have a "tin knocker" bend up a separate piece for mounting the plate.
He can do that at the same time you have the chase top fabricated.
He can bend up a 13x13 "box" that attaches to the chasetop & encapsulates the existing vent collar.
If he leaves 1" tabs at the base of the box, you can zipscrew them to the chasetop
& then silicone the crap out of thescrews & tabs.
Then you can zipscrew the plate to the top of the box.
Hope that is understandable...