Make the most of a large backyard and extend your outdoor living area with a shaded seating area with a pergola over a pathway.
The main posts of this treated-pine pergola are anchored in concrete. Make the post holes 400mm deep and 300mm wide, spaced 1350mm apart for the front and back, and 1050mm for the sides.
The frame is constructed the old-fashioned way, with tenons and housings cut into the timber with a circular saw and handsaw. It’s easier to apply the first coat of stain while the components are flat on the ground.
Keep the stain handy throughout assembly to apply on all cut ends and inside joints.
- Arbour A stand-alone lattice framework covered with vines.
- Pergola Covered, trellised area supported by columns or posts.
- Gazebo A small roofed structure screened on all sides.
Side beams are tenoned at each end to fit mortices on the posts.
Cut the beams to 1080mm and square a line around each end, 70mm in. Mark the tenon on each end with a marking gauge set at 45mm.
Set a circular saw to 45mm and cut the shoulder with several relieving cuts across the beam from both sides. Remove the waste and clean up the faces of the tenon with a chisel.
Bird’s mouth cut
Use a sliding bevel set the same as the plumb cut at the top of the rafter and transfer the angle to the measurement in Diagram 6.
Cut the bird’s mouth with a circular saw, stopping at each set-out line. Remove waste by completing with a handsaw.
Check the fit of the rafter at each location and note any adjustments before setting out remaining rafters.
For strength, fix a metal joint connector on the inside face of the rafter and place a nail plate across the back of the rafter support post and each rafter (see Diagram 6).
How to build a walkway pergola
Crosscut the housings with a circular saw, making relief cuts across the post. Clean the waste with a 25mm chisel. Cut a mortice in the remaining post section then position, housing-down, and rip lengthways. Drill 10mm holes and chisel out to the housing depth. Check for square, securing with crossties.
Stand the rear posts with the housings facing out. Use a spirit level to plumb them, securing braces. Level the horizontal ties at the base with shims. Stand the front posts and attach to the rear with horizontal side supports, checking for parallel and square. Use a level to check post heights.
Pour mixed concrete into each post hole and pack around the posts with scrap timber. At ground level, batter the concrete surface to allow for runoff and prevent water from pooling. Allow the concrete to set for a few days.
Cut a tenon at the end of each beam to match the width and depth of the post mortices. Remove the braces and position the side beams on the posts. Secure with 75mm x 10g galvanised screws angled from above.
The front and back beams require a housing at each end to fit around the top of the posts. Secure the beams on sawhorses and cut housings with a circular saw set to 70mm. Break out the waste, clean up with a chisel and smooth with a coarse file.
Lift the beams onto the posts and push back until they’re flush with the face of the posts. Adjust housing if required or tap into place with a block and hammer. Secure with 75mm x 10g screws angled from the top.
Clamp each bracket piece and cut out the shape with a jigsaw. Sand smooth with the front of a belt sander using 80 grit paper. Drill a pilot hole in the centre of the post and under the beam, securing with 75mm x 10g screws.
Use a mitresaw to cut the centre beam parts. Secure centre flanges to the centre of the centre beam to create an I-beam to support the roof parts. Screw through the bottom flange to secure the beam in the centre, set 35mm in from front and back.
Cut the ridge supports with a 45º bevel on both sides of the top and cut the ridge to length. Draw a line both sides 22mm down from the top, cut with a circular saw set to 45º. Secure the ridge support to the centre beam and screw the ridge to the supports.
Shape rafters and secure through the top edge to the ridge support with 75mm x 10g screws. Skew a screw through the inside of the rafter to the support. Skew a 75 x 3.5mm nail from each side to lock the bird’s mouth cut to the beam.
Use spring clamps to hold support battens 25mm from the top edge of the rafters. Tap in spacer nails every 180mm from the top. Cut the lattice to fit between the rafters, securing with two 75 x 3.5mm galvanised nails. Drill a 3mm pilot hole through the rafters to prevent splitting. Remove battens.
Shape braces with a jigsaw (see Diagram 4). Pre-drill 4mm holes through the braces and clamp 1900mm down from the top of the beam. Clamp each brace 20mm in from the outside edge of the post. Fasten with 75mm x 10g screws.
Cut the outer seat slat (see Diagram 4) to fit between side posts. Dock inner seat slat to 1142mm long and cut a 75mm radius each end (see Diagram 2), rounding over the outside edge. Leave a 13mm gap between slats and fasten with 75mm x 10g screws.
Secure four vertical slats 25mm from the top of the side beams into the back of the seat with 38mm x 8g screws. Leave a 175mm gap between post and slat. Cut two horizontal side slats to fit between the posts. Hold with spring clamps while attaching to the vertical slats, maintaining the gap.