angled vent stack and flexible p-trap

[mdr]

Hi,

Simple question: Does the requirement that a horizontal vent run must be 6" above the flood level rim apply to a vent run angled at 45 deg to run around obstructions?

More detailed question:


I'm correcting a remodel (previous owner) of a small 1/2 bath. Of course, I keep peeling the onion and finding more and more challenges. (In retrospect, I should have gutted and redone it, but now I've got to get the job done before my wife kills me.)

The bathroom has a pedestal sink with a chrome (brass?) waste arm that connects into the waste stack through a hubbed cast iron sanitary tee. The end of the waste arm is buried in the tee - I can't see whether it's leaded in or not. (House is from 1938). The waste arm extends too far out of the wall to fit the pedestal sink. Previous owner used flexible plastic bellows p-trap to make it work - it was lame.

From the tee, the vent stack transitions to galvanized and immediately a 45 deg bend, galvanized to another stud bay and then a galvanized 45. The initial bend is just above the waste arm and the upper bend at the rim height of the sink. Below the tee, the cast iron stack passes through the floor and then transitions to abs at a rubber fernco.

Searching the archives suggests that since I've got to muck with the cast iron tee, I should just pull out all of the metal and replace with ABS. Is this the way to go?

[jimbo]

45º angle and greater is considered to be vertical. I recommend against any kind of flexible trap. Glue up ABS is easy to work with.

[mdr]

Thanks Jimbo.

[hj]

In 1938 they probably used a brass "solder bushing" to connect the trap. Cutting it out of the tee will be IMMENSELY easier than replacing the tee in the wall.

[mdr]

Thanks for your advice hj. I have easy access to the back wall of the plumbing, so ripping off and replacing the drywall won't be too bad.

However, If I were to follow your suggestion, once the old waste arm is cut out, how would I attach the new waste arm to the cast iron tee? Your previous posts have mentioned use of a fernco rubber donut - is this what I would use?

Thanks,
Murray

[MACPLUMB 777]

Cut out all old pipe and replace while you are working and have access !

Old c.i. Pipe and fittings just cause blockages !

Go with your drawing and be " sure" to shielded couplings !

[mdr]

Thanks Jerry. I'm planning to go that route, i.e., replacing it all the CI with ABS. I won't even have to use couplings - there is ABS near the roof penetration and below in the drain line - so I'll just have to solvent into those.

[mdr]

Thanks everyone for your suggestions. I redid the drain/vent from crawlspace to roof penetration today and added a cleanout in the crawlspace. Also reworked the cold water supply so the stuboutst were centered on the trap and both stubs where at the same height.