Calculate timber for Garage roof

[checkmate]

Hi guys

I am doing my garage and wanted to but timber for the roof. The garage size is 5.5m by 5.5

The plan is to do pitched roof with felt. The pitched roof wont be too steep, its a shallow slope just so it dont look to flat.

can you advice what wood i would need and sizes? the Joyce and plywood and what the required thickness recommended?

I am supplying all materials to builder and before i ask him i wanted to have rough idea what i would need so im in same wave length

thanks

 

[theprinceofdarkness]

The first question is:- do you want a vaulted roof (clear of obstructions) or a trussed roof, cheaper but needs cross pieces running across from the bottom of opposing joists. This can be compromised into "collared" joists where the horizontal beam is not right at the bottom of the joists, but is higher, so giving increased head room for most of the width.
My commercial shed, the weight of the roof caused it to sag, by pushing the walls out in their centre. I had to retro fit ties between the end of some of the joists to stop further movement.
Frank