Vent stacks

Is anyone else running into this problem on a regular basis. I guess the codes have changed down here. This is now what we are using for a gas vent stack. I have seen this four times this week on different houses with new roofs installed.

8655 Miramar.jpg

I don’t like it. Looks like a wind from the left would create a very strong downdraft.

Jim King


My fault. What I meant to say is that this is what they are using (agianst code). The picture below shows what they should be using.

8655 Miramar Pkwy Miramar(Dorvil) 038.jpg

Do you know if it is the same roofing or HVAC guy on all the homes?
Good catch.:smiley:


No. No idea. Unfortunately it is up to the roofing company to supply the information to the building dept. when then file for a permit. If they do not tell the dept that there is an appliance or water heater that uses a stack, the city will never know (they never enter the home or look in the attic). This happens a lot down here.

Never seen picture #1 used that way up here. Show your clients manufacturers installation specs. not code. Then refer to code. if needed. When they see that manufacturer does not O.K. them to be used that way you don’t have to mention the dreadfull “C” word.


We use to design and install that type of roofvent for Bath Fan(s) or RangeHood discharge piping.
I can’t believe any reputable HVAC or Plumbing Contractor would use that type of discharge for any type of gas-fired appliance flue venting. I also can’t believe any Code or Independent Home Inspector could miss this vent problem. Could the Roofing Contractor have made this modification on his own, removing older rusted piping? Either way, I’d check or recheck it for sure, make sure I know what I’m reporting, then write it up.

This seems to be typical practice down here these days. I forget the exact height the vent is supposed to be, but I believe it is supposed to terminate two feet above the roof line. This is other vent stack was on the home behind this house. This one is correct.

8655 Miramar Pkwy Miramar(Dorvil) 038.jpg


Just checking back, I noticed your 2nd Pic of a typical and acceptable vertical “B-Vent” type flue vent. It appears older, some rust, but otherwise fine.
The other design can’t be acceptable in your area… must have been a bad choice by an unknowing or stupid Roofing Contr.