Verticle timber size for support horizontal beam timbers

[john2k]

If one was making a big timber shed with flat roof. The cross beams for the roof lets say are 7 or 8 inch by 2 inch. Is there a minimum size for the vertical beams that will act as the legs holding it up? Can the vertical timber/posts be much thinner lets say 3x2 or 4x2? Just sees funny that smaller timber holds up bigger timber

 

[sxturbo]

If the verticals are to be built like a stud wall then yes 3x2 or 4x2 be fine.

 

[^woody^]

As long as the vertical studs are restrained from bending or flexing it will be fine.