Originally Posted By: David Suelflow This post was automatically imported from our archived forum.
I inspected this home yesterday and was wondering about this vent stack. It is extended to reach above the upper roof but not by much (6-12 inches). The upper section is somewhat loose so I know I will write it up but it seems kind of out of bounds to me. Any thoughts?
Originally Posted By: jpeck This post was automatically imported from our archived forum.
Someone had some extra PVC to use up?
Depending on where you are, you could have wind load, snow loads, ugly issues, etc. Plus, that PVC is not approved for prolonged exposure to sunlight (yeah, it takes decades to begin to damage it, but a some point is will be deteriorated and brittle enough to break in the middle of that tall section, use or not use non-sunlight resistant as you choose).
Besides being butt ugly, it looks like it is attached to the wall, and is bowed out to the edge of the overhang (no 1/4 or 1/8 bends visible in that section). Wonder how long before it pulls loose from the wall?
Hopefully, they did not attach it to the roof.
They will have to remove that pipe to repair or replace the roof in that area.
Originally Posted By: David Suelflow This post was automatically imported from our archived forum.
Actually it is made of galv. pipe and no it is not attached to the structure. Thats the part I’ve written up but what about the height above the upper roof?
Originally Posted By: Peter Foxe Smothers This post was automatically imported from our archived forum.
Generally speaking the maximum height of vent pipes above roofs is 12 inches and the minimum height is 6 inches. They also have to terminate at least 3 feet above an operable door or window and 10 feet away from any door or window at the same elevation or higher.
Originally Posted By: jpeck This post was automatically imported from our archived forum.
Minimum height is typically 6".
There is no maximum height. The required height in many areas depends on snowfall amounts. You want the vent to be above the highest snow fall depth.
On roofs, when used for ANY PURPOSE other than only weather protection (such as when when mechanical equipment is installed on the roof), the plumbing vent stack terminal is required to be at least 7 feet tall (and additional bracing may be necessary).
Originally Posted By: Ryan Jackson This post was automatically imported from our archived forum.
If you read the IRC section governing this, it says that the minimum height shall be [up to the AHJ]. Sad but true…so much for uniformity among cities (and HI’s).
Originally Posted By: jpeck This post was automatically imported from our archived forum.
Ryan Jackson wrote:
If you read the IRC section governing this, it says that the minimum height shall be [up to the AHJ]. Sad but true....so much for uniformity among cities (and HI's).
Ryan,
The reason that particular section is left up to the AHJ is that they want 6" minimum, but do not want to state 6", because, in snow areas, you may need that to be 2' or 3' high.
I feel they should have put ' 6" minimum or higher, as required by the AHJ ' , but they didn't.
I know their intent because I've talked to them about this. Same thing when it was the Standard Plumbing Code, and same reason.
Originally Posted By: rking This post was automatically imported from our archived forum.
In my area of extreme cold and heavy snow (60 psi snow load structural requirements) vent stacks are not permitted to be higher than 12", or in some cases (very rare), 24".
Reasoning is the very real chance of frost closure. In most cases if the venting system is installed properly, the heat moving through the vent system from ‘that stuff’ will keep the vent open.
It is also quite common, and indeed many make a year's wages, to have the roof cleaned off after heavy snowfalls.
In this case I think it would be prudent to ask the local AHJ his/her opinion. In most instances they are willing to help.
-- Muskoka Home Inspections
"Wisdom is the Anticipation of the Consequences"
Steering Committee Member At Large