How to Build a Pergola

• Call 811 before you dig to have underground utilities marked.
• Local building codes may impact the construction of your pergola and how it is anchored to the ground.
• This is a two-person job. You’ll need to recruit a competent helper who can work from a ladder and lift the weight of a 6x6x8 pressure treated post.

Building a DIY pergola should take about 2 days. It's best to cut as much lumber as possible and prepare the site in one day, then stand up the posts and assemble the remaining parts on another day. The posts should not be left standing unattended before the corner braces have been installed.

Our example pergola is built with pressure treated lumber. This option costs less than other materials like cedar. Either type of wood can be painted, stained or left in its original color. Talk to the helpful associates in The Home Depot’s paint department for all coating options, including wood protection treatments that are clear or tinted.

Regular, untreated framing lumber isn’t recommended for an outdoor project like a DIY pergola. While all outdoor structures require some regular maintenance, untreated materials like whitewood, pine or spruce would require much more attention and expense over time.

Whichever wood is used, select fasteners that are rated for use with it. Hot galvanized or epoxy coated for pressure treated, or stainless steel for cedar. All fasteners should be rated for exterior use.

The wood parts will be joined by cutting notches and driving screws. Ornamental metal joining plates are available, too. Other design options are placing slats further apart or closer together, cutting a different shape at the end of the overhanging boards or scaling the design up or down in size.

Materials for the example DIY pergola:

• Six 6x6x8 posts, pressure treated
• Four 2x10x10 boards, pressure treated
• Four 2x10x8 boards, pressure treated
• Seven 2x4x10 boards, pressure treated
• Twelve 1x4x8 boards (lowest grade furring strips, these are for making temporary braces)
• Twelve (one pack) 3-ft grade stakes
• Fifty pack of 6-inch self-drilling structural lag screws, rated for use in treated lumber
• Two 1lb boxes of 4-inch deck screws, rated for use in treated lumber
• One 1lb box of 1-5/8-inch deck screws for use with temporary bracing
• Four post bases
• Eight .5 cubic foot bags paver base
• Cut end treatment for pressure treated lumber
• Four cable sshed anchors
• Four galvanized 8-inch eye bolts with washers and nuts

Building a pergola requires quite a few tools. Power tools make it easier but hand tools will work as well. A hand drill or impact driver will be needed to drive the lag screws. Hex-head lag screws can be driven with a wrench. Holes will need to be drilled for cable anchors. A hammer and nails could be used in place of an impact driver and deck screws.

• Shovel
• Tamper
• Post level
• Mason’s twine and line levels or laser level
• Two step ladders or sufficient scaffolding (one ladder should be at least 8 feet tall)
• Circular saw
• Hand saw or reciprocating saw
• Jigsaw (optional)
• Drill with 1/4-inch bit
• Impact driver with appropriate bits for screws
• Six-inch bit extension
• Chisel
• Hammer
• Wrench for cable anchor shackles
• Large squeeze clamps
• Measuring tape
• Rafter square
• 4 or 6 foot level
• Pencil

This DIY pergola will be constructed on post bases. Building codes in your area or the lay of the land may require some other type of base or footing.

If a hammock will be hung between the posts, use concrete footings instead of post bases.

Your pergola should be anchored to the ground. If building on post bases, a shed anchoring system that is designed for a similar sized shed will be sufficient in many environments. Once the build is complete, drill a through hole 6 inches from the bottom of each leg and attach eye bolts. Secure posts to the ground by running the cable anchors through the eye bolts and driving the anchor into the ground. Other factors like soil type or prevailing winds may impact the anchor system needed in your area.

Determine the location and mark an 8 foot by 8 foot square. If using a laser level, the easiest way to do this is to build an 8x8 square with four of the 1x4 bracing boards. Lay the boards out in a square with the ends overlapping. Drive one screw through each joint. Measure across two corners and compare to ensure that the corners are square, then drive another screw into each corner to lock them.

Use a laser level or batter boards and mason’s string to make a level line. Measure down from the level line to the ground and compare measurements between the four corners to determine high and low spots.

Remove soil from the higher points to reach a level surface.

Compact the soil and paver base with a tamper.

When cutting pressure treated wood that is to be used outdoors, it’s a good practice to retreat the cut surfaces with a treatment compound, wood preservative or exterior paint. This is especially true when the cut ends will be facing upward and may hold water.

Since construction is starting from a level surface, the posts can be their finished lengths before starting.

• Measure each post to ensure they are all the same length. Usually, the posts will be just over 96 inches when purchased. An exact length isn’t important as long as it’s at least 8 feet, but they all need to be the same length.
• To cut 6x6 posts, measure and mark the cut line.
• Use the rafter square and draw a square line on one face of the post.
• Before moving the square, use the lip that overhangs the edge of the next face to start a line.
• Roll the post so the marked side is up.
• Place the point of the pencil on the partial line.
• Bring the square to the pencil and finish the line.
• Follow suit around the post until one continuous line extends around all four sides.
• Set the circular saw to its maximum depth of cut.
• Use the rafter square as a guide to ensure square cuts.
• There will be a small piece of wood remaining that needs to be cut. Use a hand saw or a reciprocating saw to cut through it.

• A total of 8 corner braces will be needed.
• At the end of one 6x6, mark a 45 degree line with the rafter square, where the point is at the end of the timber.
• Using the method from the previous step of extending the line around the post, mark a 90 degree line down the face where the short end of the angle begins.
• Rotate the 6x6 to the opposite face from the 45 degree line and use the rafter square to mark another 45 degree line that coincides with it.
• Use the hand saw or reciprocating saw to finish the cut.
• Measure 27-1/2 inches from the long end of the angle and make a square line across the face of the 6x6.
• Use the 45 degree side of the rafter square to begin marking an opposite 45 degree angle and extend the line around the timber.
• Before cutting, verify that the angles are marked correctly. Each brace will need opposite 45 degree ends so they can brace between horizontal and vertical members.
• The final shape of each brace will be a trapezoid when viewed from the side.

The outer 2x10x10 boards will join together around the posts by way of interlocking notches.

• Measure each board and confirm that they are all the same length and width.
• If any boards are too long, cut them to 10 feet (120 inches).
• If they aren’t the same width, find the width of the narrowest board or boards and rip the others to that width.
• Measure 10-1/2 inches from one end of a board.
• Use the square to mark a line halfway across the board.
• Measure 12-1/16 inches from the end of the board.
• Use the square to mark a line halfway across the board.
• Connect the ends of those lines with another line. This defines the size and location of the notch.
• Repeat this procedure on the ends of each of these four boards.
• The notches must be on the same edge of each board.
• Confirm that all the markings are correct before starting to cut.
• Cut on the inside of each long line with the circular saw, stopping when the end line is reached.
• Use a jigsaw, handsaw or reciprocating saw to finish each cut.
• Strike the cutout piece with a hammer to remove the majority of it and clean up with a chisel.

This step is optional and is part of the design process of how to build a pergola. If you prefer the look of squared ends, there’s no reason to cut them at an angle. Other shapes, like steps and curves, are popular.

• The position of the notches that were cut in the previous step are important. Cutting these angled ends will make the boards directional.
• The notches on two boards should be open on the top edge and the notches on the other two boards should be on the bottom edge.
• At the end of a 2x10x10, measure and mark 4-3/4 inches from the top edge. Use the rafter square to mark a 45 degree line from that mark to the bottom edge of the board.
• Make these marks at the ends of all 4 notched 2x10x10s.
• Check for correct placement, then cut with the circular saw.

• All of the 2x4s should be cut to an exact length of 10 feet (120 inches) long.
• Measure and mark a line on 10-1/2 inches from each end of seven 2x4 boards. The marks should be on the same edge. This will help with alignment when placing them on top of the pergola.
• If the ends of the 2x10s were angled, cut an angle at the ends of the slats, too.
• Mark a point 1-1/2-inches from one edge and then mark a 45 degree line at that point.
• Make the same mark at the other end of each board, making sure that the angles are the same.
• Cut the angled lines.

• Standing up the posts requires a helper. These posts are heavy enough that they will cause injury if they fall on someone.
• Place the post bases into position.
• Pour some paver base on the flanges to hold them in place during this step.
• Attach the post level to a post.
• Stand up the first post in its base.
• Attach a 1x4x8 to the post with one screw, about 6 feet above the ground.
• Let the 1x4 angle away from the post to the ground.
• Lift the 1x4 up about a foot from the ground and drive a stake solidly into the ground so that the 1x4 overlaps it on the side by about one foot.
• Level the post, then drive a screw through the 1x4 into the stake.
• Add two more 1x4 braces to this first post in the same manner, on different sides.
• Once the post is standing straight, also known as plumb, drive additional screws through each 1x4 into the post and stakes.
• Repeat the procedure for standing up the second post on one side of the pergola.

• Put the stepladders in place.
• Ladders must be freestanding (do not lean them against the pergola at any time in the construction process).
• Measure 9 inches down from the top of each post and draw a line around them.
• This step uses one 2x10x10 with the notch that faces the sky.
• Align the bottom of the 2x10 with the line and the inside of the notch with the outer edge of the post.
• Use the 4-foot level to ensure that the board is level.
• Use two deck screws on each end to hold it in place.
• Check placement, then drill four pilot holes on each end.
• When placing lag screws, drill 1/4-inch pilot holes, even if the lag screws are self-drilling. The wood will split with the screws this close to the end of the board.
• Fasten with four lag screws through each end and into the 6x6 posts.

• Repeat the previous two steps to stand up and join the second set of posts.
• The other 2x10x10 board with upward facing notches will be used in this step.
• The notched 2x10x10 boards will be parallel at the end of this procedure.

• In this step and the next step, ensure that all edges are aligned to the bottom of the first boards, so that they look right from the ground.
• Lift a 2x10x10 with notches facing the ground into place.
• Lower it so that the notches interlock with the upward oriented notches.
• Hold in place with two 4 inch deck screws on each end.
• Drill pilot holes for 4 lag screws to attach to the posts, being mindful of the placement of the lag screws that have already been driven.
• Drive the lag screws.
• Repeat on the other side to complete the entire top band.

The inner supports are 2x10 boards that go around the top, but inside the posts rather than outside like the notched 2x10s.

• Measure from the inside of the outer notched 2x10 to the inside of the opposite outer notched 2x10. This measurement should be 96 inches (8 feet) but it could vary slightly.
• Cut a 2x10 to this length.
• Use a clamp to provide support, if necessary.
• Fasten the first end to the post with a 4-inch screw to hold in place then move to the other end. Put the other end in place and fasten with two 6 inch lag screws into the post. Use pilot holes and be mindful of the location of the existing lag screws from attaching the outer supports.
• Permanently fasten the first end with two lag screws.
• Repeat this process on the opposite side.

The second set of inner supports:

• The second set of inner supports should be placed so that they create the same amount of space between themselves and the outer support and the first inner supports that were installed. In other words, the inside of this board should align with the outside of the post. This will create a space for the upper end of the angle braces to fit and be fastened from both sides.
• In one corner, measure from the inside of the support that was just installed to the same point on the inside of the opposite support.
• This measurement will be approximately 82 inches, but will vary based on actual thickness of the wood that has been used.
• Cut a 2x10 to this measurement.
• Use a clamp to support the board as it's put into place.
• It is important that this board be installed square to the previous board. Use the rafter square to align it.
• Using a long driver bit and 4 inch screws, drive four screws through the fist inner support into each end of these two boards. Two screws from above and two from below.

• Before lifting into place, drill two 1/4 inch pilot holes on the thinner portion of one end of each corner brace.
• These holes should be 2 inches in from each edge and three inches up from the point.
• They will prevent the wood from splitting when the lag screws are driven through the thinner wood.
• Lift the first corner brace into position.
• The cut angle should touch the post on one end and go between two 2x10s on the other end.
• The top angle cut should be at least 6 inches into the gap between the 2x10s.
• Drive 2 lag screws through the brace and into the post.
• Secure the top end of the angle brace by driving three 4-inch deck screws through each of the 2x10s that it touches and into the brace.
• Measure from the bottom point of the angle brace up to the bottom edge of the 2x10s.
• Go to each place where a corner brace will be installed and mark a line using this measurement.
• Repeat the installation procedure with the remaining braces, aligning the bottom point with the line.

• Cut two pieces of scrap wood to a length of 10-1/2 inches. These will be used as spacers.
• Determine the direction of the slats.
• Measure and mark a line 23 inches from the end of the appropriate 2x10x10 outer support.
• Place the outer edge of the first 2x4 on this line.
• Align the 10-1/2 inch alignment mark you made on the 2x4 earlier with the outer edge of the pergola.
• Drive one angled “thumbnail” deck screw though the 2x4 and into the 2x10.
• Move to the other end and position it in the same manner.
• Thumbnail a screw through both sides of the 2x4 to lock it into place.
• Use the 10-1/2-inch spacer to position the next slat, then attach it with one screw.
• Move to the other end to space and attach it securely as before. While there, finish attaching the first slat securely.
• Repeat, moving back and forth, until all slats are installed securely.

• Accentuate it with plants.
• Furnish it with patio furniture.
• Your new pergola is ready to enjoy.
• Sit down and take a break. You deserve it after all this hard work.