An attached pergola creates a seamless outdoor living area that feels like an extension of your home. Here is how to build one that is safe, solid, and passes inspection.
The Critical Step: Ledger Board Attachment
The ledger board is a 2×8 or 2×10 that bolts directly to your house framing. This is the most important structural element. Use 1/2″ lag bolts into the rim joist, not just the siding. Remove siding first if needed and flash the ledger properly to prevent water infiltration.
Post Placement
Posts sit 8–12ft from the house (your chosen pergola depth). Use 6×6 posts set in concrete footings at least 24″ deep (below frost line). For a 12ft wide pergola, two posts. For 20ft+, three posts.
Beam and Rafter Sizing
- Main beam (post to post): 2x 2×10 bolted together
- Rafters (ledger to beam): 2×6 at 16″ OC
- Top slats (decorative): 2×2 or 2×4 at 12″ OC
