Repipe of kitchen and laundry line

[John elway]

Hey so I want to repipe a kitchen that is old cast iron and same with a washing machine they dump into a crawl space the washing machine meets with kitchen on a san t which will be changed to a wye but i want to replace it from the tie in up to the fixtures, my question is doing the connection from crawl space to up top should i plumb up to the sink or down to the main and how can i make the connection where they go into crawl space the easiest,reason is because i dont want to have to re do a small spot in dry wall in the future

 

[Cacher_Chick]

Your description does not give us enough useful information. Each fixture must have a trap, and each trap must have it's own vent. Drawings or photos can make it easier than trying to decipher a written description.

 

[Sponsor]

 

[Terry]

The vent for the kitchen sink p-trap will be higher than the p-trap. Same as for the washer drain.
Those two drains can meet in the crawlspace.
If they meet on the horizontal, then a wye.

Typical sink.