I am moving our laundry room from the basement to the first floor,I want to drain the washer into a pipe not a basin.I can easily tie into the vent line in the attic above,but what I am not sure of is what size PVC should I use and is there a rule of thumb as to how long the down line is?
I am planning to go through the floor,use a trap and tie it into the waste line for the bath sink on the main floor,will this work?Thanks Kevin

Kevin, You will use 2 inch PVC for the trap and stand pipe. If the shower/bathtub's wet vented by the lavatory drain that you're figuring on connecting to I would suppect the washer pump would pumo the discharge right out the shower drain or tub. I would use the dry vent to vent the washer but would look for another drain line to connect it to. Good luck, Tom