Rafter Depth

[chirpychippy]

When working out the depth of a floor joist in relation to the span I use the span times two + 1 inch as a ready reckoner, however, at this point in my life, I am pitching a small lean to roof. This part of the project isn't under building control nor are there any architects drawings nor eng calcs, therefore I pondering what size timbers I should use for rafters for the length I am covering. The pitch is 22.5 degrees and the length of the rafter on the underside is 2.6mtrs, maybe 2.9 overall. So if Iwere to use the joist theory then 7x2 should surfice

But to be fair, I don't think the same rule can apply, as i imagine the pitch of the roof and snow loads also play a part, could someone offer some guidance please,

 

[chirpychippy]

No one know then?

 

[Bowness72]

What centres are you planning to put the rafters in at and what is the roof covering and ceiling ?

Dont worry about the snow load as it will be less than a floor load

 

[chirpychippy]

in the end I used 6x2 rafters at 400c/c but birdsmouthed over an intermediate lintel of two lengths of 5x2 bolted together and built into the side walls, I think this is more than adequote. Thanks for replying anyway.