Colorado · Pergola guide
How to build a pergola in Colorado
4-post pergola with rafters and optional slats. A 4-post pergola frames a patio with shade and structure — no roof, minimal permit exposure, huge visual payoff.
Typical cost
$1,350–$2,144
Time
1–2 weekends
Skill
Beginner-friendly
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Permits & code in Colorado
Open pergolas without a roof are treated as accessory structures — usually no permit under 120 sq ft, but setback rules still apply. Frost depth here is 36".
State-level rules only — cities and HOAs frequently add stricter requirements. Always confirm with your local building department before you dig.
What most people get wrong
- Bolting rafters through the post — a lag from the top splits over time. Notch it.
- Setting posts without a batter board — the pergola comes out a parallelogram.
- Forgetting expansion gap on slats. They cup within a year.
The 5-step pergola plan
- Step 1Confirm site and permit pathLocate property lines, call 811 for utility marking, and check whether your city/HOA needs approval before you break ground.
- Step 2Order materialsUse the shopping list from our planner. Confirm delivery vs pickup — bulk lumber and concrete are usually cheaper delivered.
- Step 3Lay out and prep the siteBatter boards, string lines, level the base. Getting this right saves days later.
- Step 4Frame the structureFollow the cut list. Check for square with the 3-4-5 method every few pieces. Fasten with the right structural screws.
- Step 5Finish and inspectSand, stain/seal, and (if required) schedule your final inspection before backfilling or closing anything up.
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