I posted a question about adding a shower a little while ago and appreciated
the responses. Well now I am a little farther now I broke up the concrete
floor found the cast iron drain pipe but the venting has me puzzled. The
sink drain goes straight into the floor under the floor there is a cast iron
90 deg elbow looks like 3" OD this goes to the toilet drain about 2 to 3
feet away then under the toilet it must make a 90 degree turn goes another 2
to 3 feet where it meets the main drain this is also the only vent for the
toilet and sink. I was expecting to see something more for venting but the
wall behind the sink and toilet is block with no vent lines? Can I just add
a "Y" where the sink elbow is and have the shower drain tie in there with no
additional venting? the shower drain is about 3 feet away from the sink.
Thanks
Joe