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
| 18x24 ft Hip-Roof Pavilion Plan (Pressure-Treated Pine) | 20x24 ft Hip-Roof Pavilion Plan | |
|---|---|---|
| Category | Pavilions | Pavilions |
| Style | Hip-Roof | Hip-Roof |
| Footprint | 18x24 ft (432 sq ft) | 20x24 ft (480 sq ft) |
| Wood species | Pressure-Treated Pine | Composite (Trex / Azek) |
| Roof finish | tensioned 320-gsm shade sail fabric | aluminum louvered system |
| Difficulty | Advanced | Advanced |
| Build time | ~158 hrs | ~149 hrs |
| Materials cost | $16,150–$25,250 | $50,675–$79,200 |
| Footing depth | 36″ × 6 posts | 36″ × 6 posts |
| Concrete | 12 × 60-lb bags | 12 × 60-lb bags |
| Cut-list items | 7 | 7 |
| Build steps | 12 | 12 |
Cost & budget
The 18x24 ft Hip-Roof Pavilion Plan (Pressure-Treated Pine) lands in the $16,150–$25,250 range for materials in Pressure-Treated Pine, while the 20x24 ft Hip-Roof Pavilion Plan runs $50,675–$79,200 in Composite (Trex / Azek). The first plan is approximately 214% more expensive at typical 2026 lumber-yard pricing — driven mostly by the choice of Composite (Trex / Azek) over Pressure-Treated Pine and the difference in cubic concrete volume between 6 and 6 footings.
Labor & difficulty
At ~158 hours, the 18x24 ft Hip-Roof Pavilion Plan (Pressure-Treated Pine) is rated Advanced. The 20x24 ft Hip-Roof Pavilion Plan takes ~149 hours and is rated Advanced. The labor delta is roughly 9 hours, or one extra working day on the 18x24 ft Hip-Roof Pavilion Plan (Pressure-Treated Pine). 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 432 sq ft vs 480 sq ft, you are choosing between a full outdoor room and a full outdoor room. Allow at least 24 inches of clearance on every side for furniture and walking paths — that means the 18x24 ft Hip-Roof Pavilion Plan (Pressure-Treated Pine) needs a clear area of approximately 22×28 ft and the 20x24 ft Hip-Roof Pavilion Plan needs 24×28 ft.
Material & durability
The 18x24 ft Hip-Roof Pavilion Plan (Pressure-Treated Pine) is built from Pressure-Treated Pine, while the 20x24 ft Hip-Roof Pavilion Plan calls for Composite (Trex / Azek). 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, 18x24 ft Hip-Roof Pavilion Plan (Pressure-Treated Pine) 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 18x24 ft Hip-Roof Pavilion Plan (Pressure-Treated Pine) page and the complete 20x24 ft Hip-Roof Pavilion Plan page. Both ship with full cut lists, hardware schedules, footing specs, and step-by-step build instructions.