Chimney Termination Requirement

In reading my Code Check book, I confirmed that the chimney I saw today does not meet the minimum termination requirement of 3’ above any point passing through the roof. In this case, the chimney cover was located less than 1’ above the ridge. My question is why is there a minimum termination requirement for the chimney above the roof? I can see whey the 2’ within 10’ rule is there, but not this. Anyone care to comment?

BTW, this chimney had a flue cap and spark arrestor. There were tree limbs within 5’.

Is the chimney 3’ or more straight up from where it penetrates the roof? Does it also meet the 2’ within 10’ rule? If it meets or exceeds those rules it is ok.

Look at the codecheck picture #13

Hi Brian,

This should explain it. The chimney cover is only about 11". The flue cap with spark arrestor would make it closer to 24". How do you see it? Nothing within 10’ here. Just looking the min. termination height.

Hendrix Inspection 050 (Small).jpg

The IRC defers to the manufacturer for that type of chimney Hank.:slight_smile: You could write something like " the chimney is not to a standard height and we recommend checking the fireplace manufacturers installation guidelines" or something similar. Joe Hagerty has some good fireplace verbage if you can find it. He always recommends an evaluation of all fireplaces.

Hank, as you mentioned, the chimney has to terminate 2’ above any part of the roof within 10’. The visible part of the roof at the left side of the photo is within 10’ and it doesn’t look like the flue terminates 2’ above that.

The 3’ rule is probably to address the same problem as the 2/10… without adequate clearance from the roof the chimney may not draft properly.


That “chimney” looks to be the exhaust flue for a premanufactured fireplace.

I think I remember something over at that Dale Feb wrote concerning premanufactured “chimneys” not being real chimneys and falling under gas flues, Type B vents, or something similar.

Of course, I think the tree poses more problems than anything else in that photo.

Here ya go…

Looks like you’re a measley, one inch short.

Spark arrestor on a gas vent?

That’s for when a condo with gas fireplace is rented, much imbibing is done, then they throw a bunch of wood into the firepleace to get it going better. :roll: :stuck_out_tongue:

Thanks Folks. David, according to that slide, it meets the requirement. The vent cap discharge point is higher than the chimney cover, so that would work. I have to remember to differentiate between metal chimney flues for insert fireplaces vs. masonry.

Hank, David’s slide is for a gas vent not a fireplace chimney. Default is check with the manufacturer.

And don’t forget about the homeowner who likes the snap, crackle, pop, and smell of real wood, like on Valentine’s Day, Thanksgiving, etc.

As I think I remember Dale Feb stating, though, many gas fireplaces don’t have fireplace chimney’s in the traditional sense of the word. Instead, they have gas vents and so are subject to the gas vent codes rather than the chimney codes.

Many builders, however, still make the gas vent for the fireplace look like a chimney because (1) chimneys are romantic or (2) chimneys add value to the home. However, with the nature of direct vent fireplaces, chimneys (and the cost to construct them) are rapidly falling by the wayside.

It’s interesting to go to a 10,000-SF home that advertises seven fireplaces and not find a single chimney. Many of those chimneys look like the flues from the water heater or furnace. And remember that the furnace in many cases is up there in the 100,000 BTU range. So if a 100,000-BTU furnace requires only a gas vent, explain to me why a 2,000-BTU gas fireplace would require a massive chimney that is subject to chimney codes rather than a gas vent subject to gas vent codes.

I just point out that the fireplace needs to be inspected by a chimney sweep RR. :slight_smile:

Vented Gas Fireplaces: Vented Gas Fireplaces are built-in to your home just like real wood burning fireplaces, except that the flue that is a much smaller (usually 4" to 8" in diameter) and cannot handle the heat produced by burning real wood. All gas fireplaces will come with factory installed gas logs that cannot be modified or changed in any way. If you do not like the way your gas fireplace burns, you will need to replace the entire fireplace. Warning: You cannot install any of the gas logs on our web site in this type of vented gas fireplace. Doing so creates an extreme safety hazard.


Good web site.

Which would then take me back to post 4
:slight_smile: %between%

Which brings me back to posts #6, #7, and #13.

The chase cover on that Chimney Chase needs to be replaced before water-entry becomes a problem.

The top of the flue pipe should be 3’ above the point where it penetrates the roof line; it must also be 2’ higher than anything (other than the chase enclosure) within 10’.

If this flue is less than 3’ above where it penetrates the roof line, an extension piece (reccomended by the manufacturer) can be installed by a Certified Chimney Sweep to raise the flue termination to the right height. A flue termination which is too low will create draft problems for the fireplace and raising it will solve the problems.