Hi,

I am renovating an old house and have decided to add a master bathroom. I currently have 1 (ea) 2 inch vent pipe penetrating the roof line. I'd like to branch off the single pipe and run several vent pipes off the single one mentioned above to vent two bathrooms, the kitchen sink, and washing machine. As long as I stay above each "trap" would this be OK? If yes - is their a rule of thumb regarding how far above the trap the vent should be located?

Also, I'm concerned that a "horizontal" run of 4" pvc may be too big for the use. I am calculating approximately 18 DFUs (Drainage Fixture Unit) value.

Toliet 4
Toliet 4
Shower 2
Laundry 3
Sink 1
Sink 1
Tub 3
18


Finally - I've got what looks like 4" cast iron/lead line. Will a Reciprocating Saw successfully cut through this?

Much thanks for your time and thoughts.

Dan

Yes you can tie in all vents into your two inch vent. Two inch vent will carry 24 units. Make sure to tie vents in at least six inches above highest fixture flood rim level. Make sure toilet vent is two inch, and use 1 1/2 for the other vents. If your toilets are newer than 1992, then you most likely have 1.6gpf toilets which means your fixture units are only 3 for them. If over 1.6gpf, then yes they are 4 fixture units. Shower is 2, tub is two, bathroom sinks are one, kitchen sinks are two, luandry(washer standpipe, or laudry sink) are 2. Either way, you will be okay with the one two inch penetration in roof(as long as you live in an area that doesn't see below freezing temps, in which case the two inch vent should be increased to three inch before it goes through the roof.

Just make sure each fixture(trap) is vented.

And yes, a sawzall will cut through your cast iron. Just make sure to get a good metal blade and have a few of them handy, as it will burn them up pretty quickly. Run the saw at a slow rate. If you run it full open, it will burn the blade up faster. Good luck and let us know if you need any further advice.

Thanks so very much for your comments.

Will I have any trouble with the 4" line with only 14 units? I've heard that I may have trouble moving the solids.

The only solids you will have will come from your toilets, which must be at least 3". Four inch is just fine. I wouldn't worry about it at all. No need to use a smaller drain. Slope of drain is key. 1/4 inch per foot is best. Hope this helps. And come on back if you need further advice.

Excellent advice from MGD. Let me show you a typical, (in my area) bathroom group rough in. This configuration only uses one vent for the entire group.
4" ,(under cement and basements) 3" (on first and second floor) from the toilet to the main. The lavatory to connect to the toilet drain line and vent to the roof or revent back in the attic to a existing roof vent. The tub/shower to connect to the lavatory drain line and be wet vented by it as will the toilet. To exit the house with one vent we revent and tie them together in the attic. Be advised to always check local codes before changing or remodeling your drainage system.
Good luck, Tom

MGD77: nice going ! Wanted to rate your answer but... you know... I got that "reputation" thing again... :-D

Thanks.

Hi,

The Recipro. Saw and a metal blade worked like a charm. Also, your advice to dial down the speed was right on target!

Tremendously grateful.

Dan

Glad things are going smoothly.