Replacing lead drains with ABS, moving vents
I'm not a plumber, but I appreciate that most codes are developed from known deffiencies and best known methods.
I am replacing a 3 wall shower enclosure, and had my mind set on converting it to a 38" corner shower with a frameless enclosure. The old valves and vent were in the stud wall between the WC and shower that I want to remove.
I have gotten a couple of suggestions on how to do it including hammering over the old vent line, but I'm determined to do the right way, once.
My area is under 2006 UPC.
The house was built in the late 60's. I don't know what the codes were then.
There are 2 full baths, one with bath, one with shower, back to back sharing the double stud (7.5" )wall with a 4" cast iron drain stack that transitions to 2" steel vent at about 36" in the wet wall.
Off the CI stack, in the basement, is a CI double sanitary tee, each to a CI sanitary 1/4 under the WCs. The Master bath (south bath) has a WC, shower stall, and 1 lav. The north has a wc, tub, and lav. There is a lead to brass, likely custom made, (4x4x2x1.5) 4" 2 side inlets ( at 90' separation) with a 1.5" running South 7' to lav, and a 2" running East 38" to shower drain, with the closet flange attaching to the top.
The north bath has basically the same layout with the lav at the North end of the bath.
The lavs in both baths have a steel vent going up through the walls, and the tub/shower each has a 1.5" steel combining to return to the 2" steel stack vent.
The shower vent is/was 1.5" lead to 1.5" steel at about 16" high, between the shower drain and the WC that came 36" up the stud wall next to the WC then ran horizontal North to the wet wall, where it T'd into the vent from the tub, and runs back West to the stack vent.
The old shower drain was 18" from the North and East walls, but the new pan's drain is 16". Being soft lead pipe, I don't think it will survive moving and would just as soon replace it. But, because it's lead down to the sanitary 1/4 that means replacing it all.
A couple questions that stick out to me are:
Why weren't the lav and shower plumbed to share one 2" drain? It looks like according to UPC if the fixture is within the max distance (per line size) of a vented branch it shouldn't need it's own vent. Is this different because they ran it into the WC branch?
Shower stall 2 dfu
Lav 1 dfu
total 3 dfu. Easily able to use a single 2 inch line (max 6).
WC 4 dfu, is on a 4 inch line.
Does the shower/bath need a vent if its that close to the vented stack? 38" from trap to center of wc flange.
The lav would still need to be vented because its to far from the vented stack, fortunately it is already.
Am I missing something, or did they really overkill the plumbing in these baths?
There are no 90' separated side inlets available at my plumbing supply, so since a single 2" line meets the requirements (for each bath, well really for both), I am planning on using a rubber ring/gasket adapter for the CI to 4" abs, to a 4x4x2 side inlet out to a 2x2x1.5 reducing T (or wye) that goes 2" to the shower drain trap, and side reduces to 1.5 to the lav, 1/4 up, 1.5 san T to trap, then using an adapter(rubber two bands) to mate the the abs to the existing unthreaded 1.5" steel vent.
When I get to the other bath, I will duplicate on that side.
I'm not sure how to reroute the line to include the vent, since it can't T off horizontally, which would be great, or if it's even needed. I have the vent branch to the main stack vent already in the wet wall though.
The studs run North to South, both lavs would be in the same stud bay as the bath/shower drains.