If you have narrowed your shortlist to two specific designs, this is exactly the kind of decision where a side-by-side spec view saves a weekend of second-guessing. Both plans below are complete, code-aware DIY builds, but they differ on the things that matter for a backyard project — total cost, raw labor hours, footprint, and the wood species on the cut list.
Side-by-side specs
| 12x20 ft Farmhouse Pergola Plan | 12x16 ft Mission Pergola Plan | |
|---|---|---|
| Category | Pergolas | Pergolas |
| Style | Farmhouse | Mission |
| Footprint | 12x20 ft (240 sq ft) | 12x16 ft (192 sq ft) |
| Wood species | Composite (Trex / Azek) | Black Locust |
| Roof finish | open lattice rafters | HDPE shade cloth canopy |
| Difficulty | Advanced | Advanced |
| Build time | ~108 hrs | ~110 hrs |
| Materials cost | $12,900–$20,150 | $7,100–$11,100 |
| Footing depth | 36″ × 4 posts | 36″ × 4 posts |
| Concrete | 8 × 60-lb bags | 8 × 60-lb bags |
| Cut-list items | 5 | 5 |
| Build steps | 11 | 11 |
Cost & budget
The 12x20 ft Farmhouse Pergola Plan lands in the $12,900–$20,150 range for materials in Composite (Trex / Azek), while the 12x16 ft Mission Pergola Plan runs $7,100–$11,100 in Black Locust. The second plan is approximately 82% more expensive at typical 2026 lumber-yard pricing — driven mostly by the choice of Composite (Trex / Azek) over Black Locust and the difference in cubic concrete volume between 4 and 4 footings.
Labor & difficulty
At ~108 hours, the 12x20 ft Farmhouse Pergola Plan is rated Advanced. The 12x16 ft Mission Pergola Plan takes ~110 hours and is rated Advanced. The labor delta is roughly 2 hours, or one extra working day on the 12x16 ft Mission Pergola Plan. Both plans require the same skill level, so the deciding factor is footprint and aesthetics rather than your comfort with carpentry.
Footprint & site fit
At 240 sq ft vs 192 sq ft, you are choosing between a full outdoor room and a generous patio cover. Allow at least 24 inches of clearance on every side for furniture and walking paths — that means the 12x20 ft Farmhouse Pergola Plan needs a clear area of approximately 16×24 ft and the 12x16 ft Mission Pergola Plan needs 16×20 ft.
Material & durability
The 12x20 ft Farmhouse Pergola Plan is built from Composite (Trex / Azek), while the 12x16 ft Mission Pergola Plan calls for Black Locust. The species choice drives the cost delta and the maintenance schedule. Pressure-treated southern yellow pine is the cheapest and most rot-tolerant for in-ground posts; western red cedar is the DIY favorite for visible parts; redwood and white oak are heritage choices that command a premium.
Verdict
For a builder weighing these two specifically, 12x16 ft Mission Pergola Plan is the clear budget pick. If both fit your budget and yard, default to the design whose style language matches the rest of your house — a Craftsman bungalow looks awkward beside a modern slatted pergola, and vice versa.
Read each plan in full before committing: the complete 12x20 ft Farmhouse Pergola Plan page and the complete 12x16 ft Mission Pergola Plan page. Both ship with full cut lists, hardware schedules, footing specs, and step-by-step build instructions.