The first step in building a pergola: marking the territory with 2 tape measures, string, and yard stakes. Ultimately 4 posts will need to be aligned (or rather squared up). In other words, each post shall be positioned near 90 degrees perpendicular to the surface. The 3-4-5 method is a low-tech way to mark dimensions.
Digging
Once the posts are marked, start digging holes to the circumference and depth of your concrete pier (unless you already have a slab to attach the posts). The circumference and depth will depend on your geography and weather conditions – typically provided with your pergola plans.
- Before digging, call 811 to mark any underground utilities
- If you have thick grass, mow or use a trimmer to shave down the grass. Water the night before to moisten the ground.
- If there’s still grass, use a spade to carve out the grass and then use a round mouth shovel to start digging. Keep a wheelbarrow nearby to dump dirt and offload to a preferred nearby site (we were fortunate enough to dump the soil into a future bedding area).
- Depending on location, the first foot might be the easiest. Digging will become difficult with clay. Renting an auger considerably eases the job. Be careful using a single-man auger. Maintain balance by resting the handles against your thigh and performing quick, short bursts while remembering to let go of the throttle. A two-man auger is preferable.
Main parts
Most, if not all, of the beams are joined using exterior grade screws made from Spax for pressure treated lumber. These screws have a unique head that prevents stripping compared to a conventional screw or lag.
Posts: Most recommended posts will be 6″ x 6″ x 10′. A basic pergola will require 4 vertical posts – each can weigh at least 80-100lbs which will carry the load of the entire structure.
Post Brackets: Each post will be secured to a post bracket (manufactured by Simpson Strong-Tie) that is anchored to the concrete using stainless screws.
Secondary Beam: Typically 4 horizontal beams that rest on top of the posts in pairs to carry the weight of the primary beams.
Primary Beams: Typically 4 horizontal beams that stretch across our secondary beams in pairs to carry the weight of the rafters. Our primary beams are 20′ in length.
Rafters: Horizontal beams that sit on top of primary beams. These beams will start providing shade.
Purlins: Horizontal beams that stretch across rafters. Our purlins will 20′ in length. These beams provide additional shade.
Design work
Pergolas can be designed and styled multiple ways from edging to end cap millwork.
- Chamfer: a 45 degree angle chamfer can be attached to trim router to soften each edge of a post.
- Jigsaw: beam endcaps can be designed by tracing a pattern and using a jigsaw. Tip: slow down through the curves and then speed up for consistent results.
- Round-over: a small round-over bit can be attached to a trim router to clean each edge of a jigsaw-ed beam
Joinery
Typical pergolas are screwed, but can be strengthened by using supplemental joining techniques that require cutting notches or half-lap notches. These notches have some room for error, but the goal will always be to ensure a tight fit.
A regular notch can be cut by making multiple passes with a circular saw and hammering out the remaining pieces – then using a chisel to clean up. A half lap notch can be cut with a circular saw and reciprocating saw. Be sure to cut in an open area, wear a mask, and clamp down the pieces.
As always, send us any questions and don’t forget to follow our Instagram stories. Check out our most recent yard progress.