Does the washing machine need to vent to the roof or can I connect it the same way the old tub was, to basement into stack which then goes to roof, also there is a toilet and sink already in room that already vent to stack

Where I live, the vent has to be 3' or less from the standpipe. I think some codes allow for 4'.
What's important is that the standpipe be high enough (often 32" above the trap) so that sewage not back up it and overflow, and regardless of what code is where you are, that you keep the drains flowing/unclogged so this doesn't happen. You also want the slope to be adequate for drainage (1" per foot) and a proper trap so that water keeps sewer gas from escaping.

Decent info. Joypulv, but in all you provided you didn't answer the question presented... ;)

Nonhandy man asked, "Does the washing machine need to vent to the roof or can I connect it the same way the old tub was...?"

NHM, you can vent the new washing machine drain back to the old tub vent... just connect it so the vent is at least 6" above the top of the washing machine before going horizontal with it. It should be as easy as connecting onto the old vent, but without a pic. I can't say much more.

The rest of the info. By Joypulv should also prove helpful to you... :)

Adding a full-size cleanout to the drain just before it enters the larger drain pipe is also always a good idea!

Good luck!

Mark

OK Mark, but he doesn't have a spot with an old laundry tub, it's a former shower/tub.

I missed that! I can see that in the title now that you mention it, Joypulv, but the answer still holds spot on! He can vent using the old tub vent... ;)

I removed "laundry" from my answer above!

Thanks!