Hello I am plumbing a total rehab. There are two baths on the second floor and a kitchen with a dish washer, sink, and clothes washer.
the front bath drain starts with the shower a 32x32. I have to top the joist under it so as soon as possible I put a 90 and a 90 that feed into the trap. The drain then goes 18 inches and 90's toward the common wall. Along the way I have a 2x2x1.5 T that cathes the lav. Where the lav goes into the wall I have a vertical T that vents the sink and the shower. The 2 inch line continues past the sink another 5 ft and 90's again where it meets a 3x3x2 T that comes from the toilet about a foot away goes past the t by a foot and T's 1.5x3x3down to the crawl space. The 1.5 line goes straight up and over to a spot where it joins the vent from the lav and goes out side.
I will describe the rest later.
Thanks,
Matt

Hey Matt,

"I have to top the joist under it so as soon as possible I put a 90 and a 90 that feed into the trap."

You're going to install a dog leg off set to catch hair and grease before you even get to the trap raiser? Not a good idea. Rule of thumb when running drainage, the less 90's you have in the line the better drainage and the less clogs you'll have. Especially if they're unnecessary. Head off the joist and position the trap raiser under the drain. If you have the room use sweeps instead of elbos. Pick up the lavatory with 2" instead of 1 1/2" and while a 1 1/2" vent's within code the inspectors like to see 2" vents. Let me have the rest of it when you can. Regards, Tom