Im just wondering what the best layout would be for a shared apartment bathroom with 5 people in terms of allowing the most people to use the bathroom at the same time taking into account the people using the bathroom don't want to see each other naked.
For that many people, the sink, shower and toilet should be separated. Sink access is very useful on its own. Someone using the toilet shouldn't block another person from washing their hands or brushing teeth.
Layout B is better with the sink close to the entrance. Split the shower and toilet. The toilet should exit directly to the sink.
This version is the most functional, though admittedly not the most elegant. You'd see 2 doors (shower and toilet) upon walking into the bathroom. Whether the doors open outward or inward from the shower and toilet rooms depends on your preference and available space. Opening the doors outward allows the shower & toilet rooms to be smaller, but the doors will block the sink area when open.
If space is at a premium, another option is to use curtains instead of doors. The only interior wall would be separating the toilet and shower areas. Now that I mention that, you could install a tiled standing shower with an opaque shower curtain to avoid a door for it. A little less privacy, but a door isn't going to stop a determined snooper. You could have one or both with curtains (see C' with a shower curtain and toilet door). A toilet curtain would allow for a single vent to pull out both the stink and moisture. With a toilet door, you may need a separate vent in the toilet room.
For 5 people, you need:
- Separate access to the toilet in case of "emergency".
- Sink independent from shower, or they'll be a traffic jam in the morning
- Toilet door should always be able to open if someone passes out inside. So if the toilet is tiny, it should open to the outside.
In addition, bathrooms also need:
- places to hang towels (esp. for 5 people)
- enough space on both sides of the sink to brush teeth without smashing elbow into wall
#1 toilet door, opens to outside. Toilet can have a tiny sink #9 for washing hands.
#2 main door, can open to inside, using corridor.
#3 sink with space on both sides.
#4 storage, towels hanging, second choice spot for heating, shelves (five people = tons of hygiene products, razors, toothbrushes, etc, you need a cupboard for that)
#5 first choice spot for heating, closest to shower
#6 clothes and towel hanging for person in the shower, next to or above heating, to dry the towel
#8 shower door, can be a sliding door
Air extraction above shower and in the toilet.
This fulfills all conditions: in the space next to the shower, someone can undress, shower and dress while someone else is using the sink and someone else is using the toilet. Also several people can brush their teeth at the same time if they're late, because there is enough space around the sink. This type of shower allows a simple curtain instead of a door, which means much less problems with leaky doors, tenants breaking the glass door, etc.
If the bathroom is too small to be usable, make it larger.
If you need to sacrifice space, make the corridor and the main door narrower. You spend 3 seconds going through the door and five minutes in front of the sink, so it's more important to have room around the sink.