quick question advice needed please

[jj1960]

i want to build a shed out the back the space i have measures 12ft by 12ft
my intention is to use 3x1.5 inch posts every 2ft around the sides and then using 4x2 as spanning timber
the roof will not be load bearing and i am going to use weatherboard as i hate working with felt and it never seams to last
my question is for the span is 4 X 2 OK or do i need to go bigger
thanks in advance

 

[Fat ferret]

I would be tempted to go for 6x2 over 12ft if its a flat roof. If pitched 4x2 would probably be ok.

 

[MARK.B.]

Dont forget a roof that size will hold a lot of weight in snow especially if it it a flat roof so for a few quid more i would use 6x2.