How to Build a Pergola


Pergolas provide refuge from the blazing sun and are an attractive permanent addition to any garden space. Installing one doesn’t have to break your budget, either. Grab a of couple handy friends and make this simple wood pergola, which can be made in just a few days’ work.


4 ground-rated posts of 4-inch x 4-inch x 10-foot pressure-treated southern yellow pine or cedar / 11 planks of 2-inch x 6-inch x 10-foot pressure-treated southern yellow pine or cedar / 5 planks of 1-inch x 4-inch x 10-foot pressure-treated southern yellow pine or cedar / two 2-inch x 4-inch x 10-foot pressure-treated southern yellow pine or cedar / one 2-inch x 2-inch x 10-foot pressure-treated southern yellow pine or cedar / eight 10-inch-long, 1/2-inch galvanized carriage bolts with washers and nuts / eight 50-pound bags post-setting concrete mix / one box 2 1/2-inch deck screws / measuring tape / post-hole digger/ 8 wooden stakes / miter saw / drill with Phillips head attachment / two scrap pieces of 2-inch x 4-inch x 2-foot lumber / hammer / wood clamps


Select a location that is relatively flat with adequate drainage. Mark first corner with a stake. Measure 96 inches and mark with a second stake to indicate one side of the pergola. Using measuring tape, find the spot where a measurement of 136 inches diagonally intersects from the first stake and 96 inches horizontally from the second (applying the Pythagorean theorem) and mark with a third stake. Repeat the process, measuring a distance of 96 inches from stake three and 136 inches from stake two to mark the last corner. Confirm the distance between all adjacent corners is 96 inches and opposing corners measure 136 inches. Adjust as needed.


Using a post-hole digger, dig a hole at each marker to a depth of 2 feet and no less than 10 inches in diameter, making sure that the inside corner of an inserted post will rest at the marked point. A larger hole will allow for adjustments when setting posts and a sturdier foundation for the pergola once concrete is poured.


Place post in hole, making sure it rests firmly on the bottom. Using a level, make sure post sits square and perfectly level. Nail or screw an angled stake to adjacent sides of post to hold in place. Repeat process on remaining thee posts.


Concrete may be mixed directly in post holes. Pour concrete mix around the post into the first hole to 1/3 full and add water using a hose or bucket. Stir to fully combine, add a second layer of concrete and repeat. Finish filling the hole with concrete and water. Confirm post has remained level and adjust as needed. Repeat process on the remaining three posts.


Check all measurements and make certain all posts are level and facing each other evenly before concrete sets. A string stretched around all four posts can be used to confirm corners are square (string should rest flat on sides of posts. Adjust as needed. Depending on what type of concrete is used, wait several hours or overnight before continuing construction. Consult concrete packaging for time needed to fully set.


Girders are the cross pieces on which joists rest and are cut identically to joists. Measure two inches down on the end of a 2-inch x 6-inch x 10-foot plank and mark with a pencil. Leaving the measured 2 inches intact, cut plank from mark at a 45-degree angle using miter saw. Repeat at the opposite end of plank, making sure to mark from the same long edge.


Cut remaining 10 joists/girders in the same way as the first. These are the primary elements of the pergola roof and provide stability.


Starting from the top of the first post, measure down 5 1/2 inches and mark with pencil. Screw a piece of scrap 2-inch x 4-inch x 2-foot lumber to the post with top edge at marked height and parallel to the direction joists are to be run. Repeat process on remaining posts with braces all facing the same direction leveled at the same height.


Place a girder on each side of paired posts for a total of four support girders. The top of girders will be even with the top of the post. Place a level on each girder and adjust as needed. Lay a joist crosswise on top to span girders and confirm it is also level front-to-back. In cases where the ground is sloped, these adjustments may be up to several inches, leaving the top of a post exposed. Once girders have been leveled, cut post flush with the top of girders, if necessary.


Use wood clamps to hold girders in place. On the first post, measure 1 inch from the bottom and top of each girder, center on post and mark with a pencil. Using a drill with 1/2-inch bit, drill a hole at each of the two marked spots extending through both girders and post. From the outside, hammer 10-inch carriage bolts through holes and secure with washers and bolts. Repeat on remaining three posts. Once all eight carriage bolts are secure, remove clamps and support braces.


Locate the midpoint of each set of girders and place center joist to span with an overhang of 5 1/2 inches at each end. Measuring 17 inches from center joist in each direction, place two more joists. Measuring outward 17 inches from added joists, continue to add joists until all are in place and evenly spaced across the pergola.


Using deck screws and a drill with Phillips head attachment, attach all joists to girders by driving screws through joists into each girder from both sides at a 45-degree angle (for a total of eight screws per joist).


Locate the midpoint of joists (measuring along outer joists on both sides) and place a 1-inch x 4-inch x 10-foot plank to span with an overhang of 8 inches at each end. Secure with deck screws at each joist. Measuring 22 inches from affixed center roof slat in each direction, place and secure two more slats. Measure out 22 inches from added planks to place and secure final two roof slats.


Cut two 2-inch x 4-inch x 10-foot planks to a length of 9 feet.



Mitered at 45 degrees, cut eight 15-inch pieces from a 2-inch x 2-inch x 10-foot plank. Locate midpoints between center joist and adjacent joists and attach rungs to the interior of girder and trim with deck screws. Measuring outward 17 inches from the newly attached rungs, secure two more rungs on to each side. Repeat on the other side of the pergola.


A pergola will add an elegant touch to outdoor locations and can be built over patios or in natural surroundings. To give our pastoral pergola a finished look, we created a simple border using four 2-inch x 4-inch x 10-foot planks attached at the corners with utility screws. To fill in the “floor,” we used 1 square yard of #57 washed gravel raked level at a 4-inch depth.


Construction is complete. Any visible marks or spurs may be hand sanded, if necessary. Treated lumber requires no sealant, but stain or paint may be applied, if desired. Plants and pavers or mulch may be used to accessorize. This inexpensive and easy-to-build pergola will provide years of maintenance-free enjoyment.


Stringing lights along the roof of your pergola will allow you to enjoy the space at night.

Originally: How to Build a Pergola

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