First timer - Patio roof

G'day all, long time lurker first time poster.

Ive been commisioned by the boss(wife) to build a patio roof over a preexisting paved area at the rear of my home and i got a few questions.

Patio roof to cover 11.5~m x 4m.
Using Solarspan
Galv RHS Poles and beams
Roofextenda brackets x 5 - http://www.roofextenda.com.au/

I want to find out rules and regulations such as minimum footing depths and maximum roof to patio beam gap etc, is the easiest way to do this is just to get a engineer/design drawer out to my house to basically, draw it all up with the materials im wanting to use?

For people that have used solar span before - When screwing down the Solarspan onto the beam that will be above the house, do i use the reciever channel or an end barge? the only difference seems to be the barge has a facia look and hangs down?

Please suggest RHS size for poles and beams.

Im open to ideas for better products than what i have listed.

Thanks :2tsup: