/ When you are talking about beams, depth is usually the vertical direction.
You were asking about the garage. I am asking about beams...
/OK, so your garage is 6.5 metres from front to back.
Correct.
/What is the dimension from side to side.
Double garage? 2 x 7ft doors etc So say 6m external side to side.
/Which way do you want the steel beams to run.
Does it matter? Front to back say
/What sort of walls have you got to support them at each end.
Brick/block
/How many do you expect to have.
As few as necessary. 2 say.
/You mention 7 foot timbers in the OP. What are their dimensions ?why?
/and which way do these run?/q
Er from the beams to the walls? a bit longer than 7ft....
Surely its the total load of the deck + snow weight that defines all this? Spread over 4 walls & 2 beams? Add snow factor on top plus allowance?
Jim K