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
| 4x6 ft Trellis-Side Arbor Plan | 4x8 ft Trellis-Side Arbor Plan | |
|---|---|---|
| Category | Arbors | Arbors |
| Style | Trellis-Side | Trellis-Side |
| Footprint | 4x6 ft (24 sq ft) | 4x8 ft (32 sq ft) |
| Wood species | Cypress | Composite (Trex / Azek) |
| Roof finish | tensioned 320-gsm shade sail fabric | corrugated polycarbonate panels |
| Difficulty | Beginner | Advanced |
| Build time | ~16 hrs | ~121 hrs |
| Materials cost | $425–$650 | $1,100–$1,725 |
| Footing depth | 36″ × 2 posts | 36″ × 2 posts |
| Concrete | 4 × 60-lb bags | 4 × 60-lb bags |
| Cut-list items | 5 | 5 |
| Build steps | 9 | 9 |
Cost & budget
The 4x6 ft Trellis-Side Arbor Plan lands in the $425–$650 range for materials in Cypress, while the 4x8 ft Trellis-Side Arbor Plan runs $1,100–$1,725 in Composite (Trex / Azek). The first plan is approximately 162% more expensive at typical 2026 lumber-yard pricing — driven mostly by the choice of Composite (Trex / Azek) over Cypress and the difference in cubic concrete volume between 2 and 2 footings.
Labor & difficulty
At ~16 hours, the 4x6 ft Trellis-Side Arbor Plan is rated Beginner. The 4x8 ft Trellis-Side Arbor Plan takes ~121 hours and is rated Advanced. The labor delta is roughly 105 hours, or one extra working day on the 4x8 ft Trellis-Side Arbor Plan. If you are newer to outdoor woodworking, the 4x6 ft Trellis-Side Arbor Plan is the safer pick — it uses simpler joinery and fewer compound cuts.
Footprint & site fit
At 24 sq ft vs 32 sq ft, you are choosing between a focal-point garden structure and a focal-point garden structure. Allow at least 24 inches of clearance on every side for furniture and walking paths — that means the 4x6 ft Trellis-Side Arbor Plan needs a clear area of approximately 8×10 ft and the 4x8 ft Trellis-Side Arbor Plan needs 8×12 ft.
Material & durability
The 4x6 ft Trellis-Side Arbor Plan is built from Cypress, while the 4x8 ft Trellis-Side Arbor 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, 4x6 ft Trellis-Side Arbor 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 4x6 ft Trellis-Side Arbor Plan page and the complete 4x8 ft Trellis-Side Arbor Plan page. Both ship with full cut lists, hardware schedules, footing specs, and step-by-step build instructions.