I have a modular home and I'am having an addition added on for the kitchen,so I'am moving the sink and all cabinets including the counter out ten feet. I have a crawl space under to run my ptrap down but I don't know where I need to tie in the vent pipe because it's back ten feet in the old wall??

KDCSBMC50...

The vent for the kitchen sink will most likely run in the outside wall and go up and into the overhead joist bay to run over to spot that joins another vent (old vent) or the kitchen sink vent will penetrate the roof by itself (increase vent to 2" just before penetrating the roof).

The ptrap will go under the sink for best results.

If there is a window above the sink then the vent will run under the window(s) (yup! Going to have to drill the studs... ) and over to nearest stud bay and vent will run up this bay and into the joist bay above, etc...

Check out my picture below...

Let me know if this makes sense...

MARK