We recently purchased an older duplex that has been rented out for some time. The resident of one half moved out and we were starting the process of fixing it up to rent again, and decided to remove the ugly sheet flooring and replace it with something new.

Upon pulling it up we discovered massive water damage to the floor and sub-floor and consequently we needed to remove the cabinets to be able to access all of the damaged sub-floor, and the leaking drain pipe in the wall.

We also then found the tub had been leaking damaging the drywall, the floor and sub-floor, and many of the wall studs. Yay.

I've removed the sink and the tub and (soon) the toilet as well as most of the drywall, floor and sub-floor, and now need to decide on the design for putting it all back.

However in looking at what is there, its not clear that what is there is up to code, or done right in the first place.

This is a picture of the 4" cast iron main drain immediately beneath the toilet:

The line leaving the drain at an angle is a 2" PVC pipe that heads towards the kitchen where there is a 1 1/2" washing machine drain (that might not be vented) which then continues on to the front of the building where it turns up next to a window near the kitchen sink, where there was a san-tee with a 1 1/2" fixture arm for the kitchen sink (that was massively leaking). and continues on up through the roof as a 1 1/2" galvanized steel vent pipe.

The end of the line in the kitchen:

and here is the proposed solution for the kitchen:

The other pipe coming off of the main drain:

travels about 6 feet to this:

Where the tub fixture arm can be seen in the background, and the pipe continued up from there past a tee for the bathroom sink and continues up through the roof as a 2" vent.

Is anything right about this?

As the very least it seems the bottom tee should be a Wye and 45 and the pipe heading toward the main drain should slope down rather than slightly up as it did.

But it also seems that the toilet might not be vented or might be wet vented or something.