I am looking to build footings for three 6"x6" patio cover posts which will support a 6"x8"x19ft beam for a 19ft wide x 16ft deep patio cover that will fix to my house using a ledger board. We have an existing 4" concrete slab. Looking at the cleanest option/smallest opening for concrete footers that will support these beams. Anchoring the bases of the posts using red head anchors. My area calls for a 14" wide x 14" long x 12" deep footing for the post.
Should I cut out a 14 x 14" square in the concrete to dig a hole below it to fill with concrete? Can I cut a smaller hole but dig deeper to use a concrete tube?
Appreciate any guidance.