How to Build a Pergola With a Built-In Bench

Step 1: Locate and Level

Select an area that needs a pop of interest or that needs to be screed out. Level out the area near and around the bench with a shovel to create consistency for measuring.

Step 2: Dig Holes and Set Posts

Use a shovel to dig out four 12” wide and 20” deep holes (8’ 8” apart long wise and 20” apart short wise). You want the back posts to sit 8’ apart from the outside of the posts so a 1x6 x 8’ board for the seat lines up with the far end of the posts. The front post should sit 18” apart inside post to inside post. Optional: Roll out landscape fabric under the bench to reduce the potential for weeds. Secure with landscape nails.

You can adjust the dimensions of your bench to your liking, but a good width is between 16” to 22” wide. If your bench is 6’ long or shorter, you can skip the middle post. If you make the bench longer, add a center support post every 4’ or so.

Drop your first 4x4 x 10’ post into the hole, then use a 3’ level to make sure it’s plumb. Mix concrete according to package instructions, and pour three bags of in the hole. Use supports to hold the post in place until it sets. Next, place the second post in its hole, then use a tape measure to measure the outside of the posts to 8’. Then, pour the concrete and use the level to check plumb. After the back post is set, use clamps to make sure the front posts are spaced 18” apart and plumb to the back posts. Fill each hole with about three bags of concrete.

Step 3: Build Bench Frame

Use a chop or circular saw, and cut the two 2x4s to 7’ 9” and two 2x4s to 18” long. Measure 16” up one post from grade soil level. Use a level, drill and screws to mark and secure each 2x4 to create a box. They should all fit within the frame. Note: If your property has a slight slope, pick the high corner and measure 16” up. Use a level to pick the location of the other 2x4s based on that first post.

Step 4: Attach Bench Support

Dig a 12” x 14” hole in the center of the rectangle (This can be done in step 2 as well). Cut the remaining 4x4 to 30” long, set the 4x4 post 1’ into the hole and pour concrete around it. This extra post will keep the bench from sagging and will help support sitting weight.

Next, cut a 2x4 to three 15” boards, and attach the center one horizontally on top of the post and line up with the top of the frame. Attach the other two 2x4s vertically about 2’ in from the end.

Step 5: Complete Bench

Take the 1x6 x 8’ board, and line it up against the back 4x4 posts. Use a drill to secure with 1-1/2" screws. Take another 1x6 x 8’ board, and line it up against the front 4x4s. Attach it with screws. Lastly, take the remaining board and space it out evenly between the other two boards and secure with screws. This should leave you a 1/4“-1/2” gap on either side depending on how your boards were factory cut.

Step 6: Attach Decorative Cross Beams

Find the center of one of the 2x10 x 8’ boards, and measure 3” up. Next, measure 2' on either side from that center line. Connect the points by measuring a few spots equally on either side (Image 1). Use a jigsaw to cut out the detail (Image 2).

Next, measure up and mark 7' 6" up on the front posts, and attach the beam with 3" deck screws (Image 3). Line up the 2x8 x 10’ so it hides the top of the fence, and attach with screws (Image 4).

Step 7: Cut Decorative Back Rest

Clamp the last two 1x6 x 8’ boards together to the 4x4 posts. Find a back height that suits you (Ours starts 9” up from the bench seat). Measure out and draw three 1’ rounded diamond shapes using a pencil and tape measure (Image 1). You can also cut a template out of cardboard and trace it. Secure the boards with clamps, then cut the decorative back support with a jigsaw (Image 2).

Step 8: Attach Supports to Back Rest

Line up the 1x6 boards, and smooth out misalignments with a sander. Next, cut two scrap 2x4s to 11”, and attach with 2” screws. Evenly space the supports between the diamond cutouts to stabilize and strengthen the back rest.

Step 9: Attach Back Rest

Attach the 1x6s with 1-1/4" screws starting 10” up with a right-angle bit if you are up against a fence or a wall. You'll want to countersink or inset the screws into the wood 1/4 of an inch so it grabs into the 4x4 more.

Step 10: Attach Angled Cross Beams

Attach the 2x4 x 10’ spaced 1-1/2” above the back 2x8 for additional screening. Then, measure and cut two 2x4 side supports to fit between the back 2x4 and the front 2x8. Attach to the outside of the 4x4s. Next, cut three roughly 26-1/2” center cross beams (measure to be sure) with top notches using a jigsaw.

Step 11: Stain Wood

Add a stain to protect and color the wood, paint it or leave it to weather naturally.

Step 12: Add Finishing Touches

Add pillows and seat cushions to the bench. Plant something like pink flowering wisteria that will quickly grow over the top of the structure and will add much-needed greenery to your backyard.