I am building an addition and moving washer/dryer and laundry tub into it. I will also be adding another laundry tub for my shop, which will be on just behind a common wall with the new laundry room. I am planning to run the water lines in copper because I was told that DYIers can not run PEX here.

Anyway, a couple of questions:

- when I branch off of my water lines to run out to the new laundry room, can I run 1/2" copper all the way to the new laundry room to feed the washer and two laundry tubs? Or do I need to run 3/4" and then branch off 1/2" for each appliance/fixture?

- can I have one main shut-off on each line (hot and cold) where I branch off from my existing plumbing? Or do I need to have one at each appliance/fixture? Or can/should I do both? The reason that I want one on the main line is that this will just be a rough in for now, and I am not sure when I will finish the laundry room. There is also an outside chance that the new laundry room will remain unheated next winter (in MN) and I don't want the lines to have water in them. But I need to rough them in now before my framing inspection on the addition, so I want to put the shutoffs in to keep everything dry for now.

As always, thanks for the help. I am a slightly less dangerous plumber because of the help that I get here...