ABOUT CONCRETE FOOTERS
All Pergola and Patio roofs require concrete pier footers, no matter what the building materials are. The only way to escape this is if your columns can be attached to a thick concrete patio.
Footers are expensive, but unavoidable. The average footer required is a 36" x 36" x 36" cube. Each hole is dug big enough to fit a family or protect a squad of soldiers! Excavating that dirt being replaced by concrete is also laborious and costly, requiring special equipment and trucks.
You are welcome to hire your own concrete company or someone else to do your footers, however that complicates permitting. If you research you'll find Concrete Footers cost $$$! As an owner/builder you can do your own footers as well...
BUT IT'S BETTER TO LET US DO THE FOOTERS THOUGH