A DIY wood pergola material cost typically ranges from $1,500–$5,000 depending on size and lumber species. A 12×16 ft cedar pergola with 6×6 posts and decorative rafters runs approximately $2,000–$3,500 in materials. Pressure-treated pine costs 30–50% less than cedar or redwood. Professional installation adds $2,000–$6,000 in labor. Prefab kits range from $500–$4,000.

For a freestanding pergola, use 6×6 posts for any span or height. For an attached pergola (ledger-mounted to house): 4×6 posts for spans up to 8 feet; 6×6 for wider or taller structures. Post length = desired height + burial depth (at least 2 feet in ground, or 4–6 inches above concrete slab on post base).

Rafter span is the distance between supporting beams. For 2×6 rafters: max span is about 10 feet without a supporting beam underneath. For 2×8 rafters: 12–14 feet. For 2×10: up to 16 feet. Wider spans require either mid-span support beams or larger rafter stock. Decorative cantilever ends should not exceed 1/3 of the total rafter length.

Use 2–3 bags of 80lb concrete per 6×6 pergola post in a 12-inch diameter × 24-inch deep hole. Corner posts and end posts should use 3 bags each. For a standard 4-post pergola, plan on 8–12 bags of 80lb concrete. Fast-setting concrete is convenient — pour dry into the hole, add water, and the post can be loaded in 4 hours.