How to build a stud wall around a small window

[cowboy25]

This is for a small window for a bathroom in a shepherds hut which I'm building from scratch. The bathroom is very small so will just have one small window. The size of the wall space is w 121.6 cm by h 195.2 cm and the window is w 48.5cm x h 91cm. Obviously the wall space is quite small so I was wondering if I can just have two vertical studs with the window,window header and window sill contained within as in diagram B. Would this be structurally sound? Or do I need 4 vertical studs as in diagram A?

 

The first photo is the window and the second photo is the bathroom wall space in question between the existing vertical studs.

 

Edited 5 hours ago by cowboy25

[Nickfromwales]

Diagram B every time 👌. 

[Nickfromwales]

If the gaps exceed 600mm add 2 pieces as shown. 
 

[SimonD]

Is this timber frame wall a load bearing wall or is it just internal framing? If it's load bearing then you really want to follow standard timber framing methods. I would almost always use the 3rd option from left, but sometimes use option 1 if short of cls.