Vent pipe in attic - InspectionNews

Richard Roshak · #1 (**permalink**) 06-03-2008, 02:13 PM

The owner ran this plumbing vent up, over and down, so that he could install pull down stairs. I don't think this is a problem, however I thought I would ask to be sure.

Rich

Jon Randolph · #2 (**permalink**) 06-03-2008, 02:32 PM

By up, over and down I assume that you mean he created an upside down u (or an n) with the vent pipes. If so, this is wrong. It will trap rain water and condensate in the section that goes up and through the roof.

BTW....

I always write up those cheap pull down stairs as low quality and caution the client about relying on them to enter/exit the attic safely. I also list them as a breach of the fire separation between the home and garage if installed in the garage, unless provisions have been made to resist fire.

Richard Roshak · #3 (**permalink**) 06-03-2008, 02:36 PM

It does not go through the roof and it terminates into a main vent.
Rich

Jim Luttrall · #4 (**permalink**) 06-03-2008, 05:57 PM

Vent is still wrong, needs to slope and not trap condensation.

Jerry Peck · #5 (**permalink**) 06-03-2008, 07:15 PM

A vent needs to "vent".

That's a large trap, that is not going to "vent" (at least not properly).

He would have been better off (and it would have been easier and cheaper - less pipe) to 'go around'. Sloping uphill as he went 'around'.

Brandon Whitmore · #6 (**permalink**) 06-03-2008, 07:28 PM

Like everyone else has said-- wrong. Everything must slope back toward the sewer line.

Richard Roshak · #7 (**permalink**) 06-03-2008, 07:33 PM

Lost my head today. 1/4" per foot back to the main drain/vent.
Rich

Jon Randolph · #8 (**permalink**) 06-04-2008, 05:08 AM

Quote:

Originally Posted by Richard Roshak

Lost my head today. 1/4" per foot back to the main drain/vent.
Rich

That is the minimum for waste piping but as long as there is some slope in the vent piping, I wouldn't get excited. You don't have to worry about solids settling out in the vent, unless it is a wet vent in which case it becomes waste piping.

Tony Watson · #9 (**permalink**) 06-06-2008, 04:41 AM

If both Horizontal pipes are slopped in the direction that they would drain, then this configuration will work. The pipe size though is another issue. The configuration as shown looks like an "island vent", without a sink draining into it.

Joshua Hardesty · #10 (**permalink**) 06-06-2008, 05:32 AM

Tony: I don't believe the photo shows two vents flowing away from eachother that tie in above where we can see adn then shoot out the roof. We're looking at what used to be one long horizontal vent running near the floor, that the homeowner jogged up out of his way so they could put in an access to the attic, so both horizontal pipes are sloped the same way.

Tony Watson · #11 (**permalink**) 06-06-2008, 12:36 PM

Quote:

Originally Posted by Richard Roshak

It does not go through the roof and it terminates into a main vent.
Rich

If one side ties into a vent TEE and the other side is the upper section of a common or individual vent then both sides have to drain to a stack, with the right grade of course.

Jerry Peck · #12 (**permalink**) 06-06-2008, 01:29 PM

Quote:

Originally Posted by Tony Watson

If The configuration as shown looks like an "island vent", without a sink draining into it.

Tony,

Think of it as a "high loop" instead of an "island vent".

The island vent is tied back down to the drain, creating a vent path.

That is a high loop, not tied back down to anything, creating a trap (inverted trap, which traps air).