Chimney Height for combustable gas

The chimney in the picture doesnt follow the 3,2 10 rule. It appears to be about as high as the ridge.

In the picture it is hard to tell.

In the archives I submitted a post pertaining to chimney height.

J. Pope replied that being a gas appliance it follows a 8 ft. rule and needs to extend 1 ft. to 8 ft. vertical. If the roof slope is < 6/12 than 1 ft. is acceptable.

So according to that statement the chimney height is OK.

Therfore I dont need to call it out as being to low.

Is that correct?


A rain cap should be recommended for this chimney.

Dave, this is a vent rather than a chimney and therefore falls under a different code, Jeffs advice is sound, but to expand on it a bit here it the abridged table from IRC 2426.6.5 and UMC T8-1

  • 6:12 pitch = 12 inches
  • 6;12 to 7:12 = 15 inches
  • 7:12 to 8:12 = 18 inches
  • 8:12 to 9:12 = 24 inches
  • 9:12 to 10:12 = 30 inches
  • 10:12 to 11:12 = 39 inches
  • 11:12 to 12:12 = 48 inches

The “chimney” is realy a decorative feature and from a code perspective not part of the vent requirements.

I hope this helps




Thank you for the information.

In my report would you still note this as a chimney for location & type?


Location…East slope…Chase…Framed…Flue…Metal

I need to look closer at the chimney to see if it is missing a cap like Tyrone metioned.

I was there yesterday setting up the radon monitor at a vacant home and did most of the inspection. The roof was snow covered and I didnt inspect it yet.



Jeff and Gerry’s info is right on. However, if you are in a non-ICC area, check National Fule Gas Code, from which the ICC info is borrowed.

i’m assuming that the post is for the “chimney” on the left and up hill and not the “vent” of P.V.C to the right, right? or left, or correct…great now my brain hurts.

:slight_smile: :slight_smile:

Jay; Calm down, I think your brain is venting, to many vents. ha. ha. :wink:


In threw the nose…out threw the mouth…in…out… thanks Marcel. i feel much better now.