How to Build a Pergola Step by Step | DIY Backyard Build

For the full breakdown, see our best DIY Pergola Kit guide.

You can build a pergola step by step even if you’ve never framed anything larger than a raised bed. The secret is method: confirm your footprint is square before you dig, get every post plumb and every beam level before you commit, and let the concrete cure before you load the structure. Here’s the order that works.

Before You Dig: Permits, Utilities, and Layout

Check with your local building department about permits and setback rules before buying lumber. Freestanding structures near property lines or decks often carry specific code requirements.

Call 811 at least a few days before digging so utility lines get marked for free. Home Depot’s own build guide leads with this step — skipping it is the most expensive mistake on this list.

Marking a Square Footprint

Stake out the four corners of your pergola, then measure both diagonals. When those two diagonal measurements match, your layout is square. If they don’t, shift the stakes until they do — this is the step that keeps the whole frame from racking later.

Setting Posts: Holes, Concrete, and Plumb

Dig each post hole about 12 inches wide and at least 24 inches deep in most climates. In cold regions, go below the local frost depth so winter ground movement doesn’t heave your posts. Add a few inches of gravel at the bottom of each hole for drainage unless your design specifies otherwise.

Set each post in concrete, bracing it with temporary stakes so it stays perfectly plumb while the mix cures. Check plumb with a level on two adjacent faces of the post. A post that leans even slightly becomes a beam problem two steps later.

If you’re building over an existing concrete patio, skip the holes and use surface-mounted post bases or anchors instead — these bolt to the slab and hold the posts off the concrete so they don’t wick moisture.

Framing: Beams, Rafters, and Fasteners

Once the concrete has set — 24 to 48 hours minimum, longer in cool or damp weather — attach the beams that run between posts. Use galvanized bolts or structural screws rated for outdoor use; carriage bolts through the post into the beam is the classic connection. Keep beam tops level and consistent in height across all posts.

Lay rafters perpendicular across the beams, spaced evenly per your design, and fasten each one with hurricane ties or structural screws. If you want the shaded lattice look, add top slats or trellis panels running the other direction.

A common beginner setup uses 8×8 posts on an 8-foot by 8-foot footprint with 10-foot posts, giving roughly 8 feet of headroom after setting. Scale the footprint up or down as your space allows.

Before you finish, double-check that every post is still plumb, every beam is level, and all post tops sit at the same height — rechecking before final fastening is far cheaper than shimming after the concrete hardens.

Finishing Touches: Curing and Sealing

Let the concrete cure fully — most guides recommend 24 to 48 hours before structural load, but longer is safer in cool conditions. Keep the post bases braced until the concrete reaches strength.

Apply stain or sealer only after the lumber has dried out completely, which can take a couple of weeks for pressure-treated posts. Sealing wet wood traps moisture and invites rot.

If the thought of cutting and leveling this many pieces feels like more weekend than you want to spend, a ready-to-assemble pergola kit removes most of the layout and cutting work — our roundup of the best-rated kits compares sizes, materials, and price points so you can match one to your patio.