Critical Steps to Building a Freestanding Pergola

Freestanding pergolas have at least four posts and like their name says, stand without being attached to any other structure or wall. They are typically located independent of any anchored surface like a deck or patio and therefore require the posts to be sunk into post-hole footings or to have the posts surface mounted to concrete footings. Be sure your freestanding pergola is properly anchored for worry free enjoyment. Anchoring pergola posts to paving stones is not an acceptable method of anchoring.

The advantage of building a freestandingpergola is there are no limitations on total size, height, or orientation. There are however always limits to the span of the beams. Unless you are working in structural steel (and we do work with that quite often), spans should be limited to twenty feet between posts to avoid special orders and special prices that go with extra-long lumber.

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.

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. Then secure each end with four 3-in. No. 10 screws.

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.

Post Trim and Braces

Next step to building a freestandingpergola is to cut the post trim pieces 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 trim pieces to the posts with construction adhesive and galvanized finishing nails.

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.

Capping the Posts

Last step to building a freestandingpergola  is 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.