In my house I have an 8x10 foot closet that I want to darkroomify. It buts directly up to a bathroom. On the other side of the wall from this closet, there is a bathroom with a shower/tub combo installed (with tile) directly on the other side of the wall from the closet. If I wanted to get real destructive, I could just tear that wall out and combine the closet and bathroom into a darkroom, but that approach lacks WAF.
The problem with the closet is there is no ducting into it, no plumbing, and no ventilation. The bathroom, on the other hand, has a duct in the ceiling and also has an exhaust fan in the ceiling.
My plan is to put a "T" into the ductwork going into the bathroom ceiling A/C duct, and run that it into the closet ceiling. This will cut the air going to each by 1/2, but I can have adjustable ceiling vents to close one room or the other off room off.
Then I will install a bathroom exhaust fan in the ceiling of the closet and "T" that into the same vent the bathroom exhaust fan goes too. The bathroom ceiling fans I have looked at all have 1-way valves installed in them so this should be enough to prevent crossover (no point in venting the darkroom fumes into the bathroom or vice versa).
For plumbing, I suppose if I cut a hole in the drywall in the proximity of faucet-side of the tub/shower combo that is installed on the other side of the wall, I will be able to see the plumbing and tap into both the drain and the hot/cold lines for my darkroom sink.
I'm not a plumber, HVAC person, or electrician, but those are my thoughts. Do you think it's worth approaching?