Hello there.

I�m building a pergola ~13� square from post to post and would like to some help to see if it�s structurally sound. This is my first time building this and would like to ask for help from the experts out there. Our plan is to have either Wisteria grows on top of this structure or perhaps some table grape vines. This structure is located in Rocklin, CA (Sacramento). Ground is somewhat hard and have quite a lot of river rock in ground. Open for suggestions and modification to ensure structure sound and hope that cost won't go through the roof.

Already done:
Poured 12" concrete tub footing � at ~ 2 ft deep (5000 psi commercial concrete)
Bracket is embedded within concrete footing
It�s 3" off the ground from the base of the bracket

Planning to use the following lumbers but open for changes to ensure structure sounds and no sagging
Use Redwood for this structure( but considering Dougfir or treated fir if the expert recommend)

1. 6"x6" x 7� or 8� columns (4 columns) (I can either keep 8� height or can trim it to 7")
2. Stack on top of the columns are 2 cross beam of 6"X 8"X 16� (with ~13�.3" unsupported spanning)
3. Stack on top of the cross beams are 8 rafters of 4"x 6" x 16� (the intention is to have 2 ft spacing)�try to maximize the space without creating sag problem
4. 2"x3"x16 or 2"x2"x16� (32) for lattice � 4-5" spacing

Many thanks in advance,
Lad