Here's a structure that won't provide shelter from wind or rain, and is only marginally better when it comes to the midday sun. So, why build it? Because in the absence of walls and a roof, it defines an outdoor space without constraining it. It's a unique architectural blend that places you both inside and out at the same time. The structure is called a pergola, and it's just the thing to bring backyard landscaping to life. Pergolas were common features of Italian Renaissance gardens, often covering walkways or serving as grape arbors. Today, the same design can be used to define a passageway or frame a focal point in your yard. Add a climbing plant such as wisteria or, yes, grapevines, and your pergola will provide color and shade as well.
Our pergola fits on an 8-ft. square, but it's easy to modify it to suit your site. Cedar is our material of choice because it resists decay. Leave it unfinished and let it gradually turn gray. Or, apply a stain or sealer designed for exterior use.
Installing the Posts
The posts are composed of pressure-treated 4 x 4 cores that are sheathed with 1 x cedar. We secured the post cores to a concrete pad with steel post-base anchors. If you're not building on a pad, use longer posts and set them in the earth below the frost line.
Lay out the post positions and mark the screw locations.
We used 1/4-in. Tapcon screws that thread into 3/16-in. holes bored with a hammer drill.
Hold each post plumb and drive nails through the anchors into the wood. If necessary, brace the posts so they stay plumb.
Attaching the Support Beams
Cut the four 2 x 6 cedar support beams to length, use a template to mark the curved notches at the ends and cut the notches with a jigsaw. Clamp the beams in place, and check that they're level and that the posts are plumb.
When adding the second of each pair of beams, check that they're level across the top edges.
Adding the Crossbeams
The 2 x 6 crossbeams are notched to fit over the support beams.
Cut the notches with a dado blade in the table saw, or lay out each notch and use a jigsaw to remove the waste.
Then, make the curved end cuts.
Install the crossbeam pairs at the posts first. When they're in place, bore screwholes down through their top edges and screw crossbeams to the support beams. Then add the three remaining pairs with similar spacing.
Post Trim and Braces
Cut the post trimpieces to length and width. Note that you'll need to notch some of the pieces to fit between the support beams, or you can make filler blocks to cover the post cores at these areas. Instead of trying for perfectly flush corners, we dimensioned the trim to leave a 1/8-in. shadow line, or reveal.
Secure the trimpieces to the posts with construction adhesive and galvanized finishing nails.
Use 2 x 6 stock for the diagonal braces. Cut the ends to length at 45 degrees, and use a flexible stick to lay out the shallow curve on the lower edge of each brace. Fasten the braces to the posts and beams with screws.
Fitting the Top Slats
Cut the five 2 x 4 slats to length and shape the ends.
Clamp each slat in place and mark the crossbeam notch positions.
If you use a table saw and dado blade to make the cuts, be sure to support the long stock at the opposite end.
Then, bore pilot holes and attach the slats with 3-in. No. 10 screws.
Capping the Posts
To make the post caps, cut square blanks and then set the table saw blade to 15 degrees for shaping the bevels.
Use a longer board with a stop across the end as a sled to guide each blank through the blade. Clamp the blanks to the sled when making the cuts.
Secure the caps with 6d galvanized finishing nails and construction adhesive.