Gather your supplies
- Wall plate 140 x 45mm H3 treated pine
- Posts 90 x 90 H4 treated pine
- Beam 190 x 45mm H3 treated pine
- Rafters and blocking 140 x 45mm H3 treated pine
- Fascia 230 x 18mm primed treated pine
- Gutter 100mm quad gutter, stop ends, brackets, downpipe outlet and 100 x 50mm downpipe
- Roofing Colorbond Steel Trimdek roof sheets and custom-fabricated barge cappings and flashings in Monument
- Ceiling Lining HardieGroove fibre cement sheets
You’ll also need
Post-hole digger; spirit level; 125 and 100mm batten screws for treated pine; timber for bracing; clamps; circular saw; stringline; sliding bevel; builders square; concrete mix; crowbar; combination square; framing nail gun and nails; chalkline; metal strapping; tensioning clips; timber connector nails; Multi-Grip connectors; sarking; foil clips; galvanised flat head nails; pop rivets; pop rivet gun; clear silicone; tinsnips; wide vice grips; 50mm roofing screws; hired panel lifter; fibre cement screws; angle grinder fitted with a diamond cutting blade; dust mask; acrylic gap filler; exterior wood putty; sandpaper; exterior paint; painting gear
For you to note
Check with your local council for pergola size and position regulations you must comply with before building.
Determine positions of posts along the front of the pergola. Lift pavers and dig 800mm deep holes at post positions using a post-hole digger.
Cut wall plate to go along extent of your pergola. Determine height of wall plate, which here allows the roofing to fit under the fascia on the house. Hold against the wall, make level and screw into the wall studs using 125mm batten screws. Use two screws per stud. Use masonry anchors for brick walls.
Sit uncut posts into holes at each end of pergola, make plumb and temporarily brace. Mark level of top of beam on post, which will also be top of post. Allow at least 50mm of fall on the roof for every metre it spans.
Remove post and use a circular saw to cut posts to length then cut a 140mm long and 45mm deep rebate in the top of the posts. Reposition posts in holes so rebates face inwards, make plumb and brace again
Sit beam in rebates on posts, leaving it long in case you need to adjust position of the rafters along it. Make sure it is level, adjusting the length of the posts if necessary. Clamp to hold.
To get the angle to cut on the ends of the rafters, run a stringline between the top of the beam and the wall plate. Set a sliding bevel to the angle where the stringline meets the beam and plate then transfer this to the rafter. Cut to length.
Lift rafter in position at end of pergola, butting the ends into the wall plate and the beam. Screw in position to hold using 100mm batten screws. Check your pergola is square by using builders square in the corner where the rafter meets the beam. If building a pergola that is open on 3 sides, measure diagonals to check they are the same. Adjust position of posts and rafter on beam as required.
To make sure beam is straight, run a stringline along the top corner from end to end. Cut and fit a rafter into the centre of the pergola so the beam meets the stringline.
Run a stringline between the bottom of the end posts then cut and fit intermediate posts along the beam so they meet the stringline. Make sure they are plumb then screw all posts into the beam.
Concrete posts in position using a crowbar to make sure the concrete is thoroughly mixed. Leave to set.
Along faces of beam and wall plate, mark out positions of rafters using a combination square. Space rafters about 600mm apart. Also position rafters so that the edges of the sheets that will line the underside of the pergola will sit on the centre of a rafter, installing extra rafters if required. Nail to hold and then screw to beam and wall plate using batten screws.
Along underside of rafters, use a chalkline to mark position of blocking that fits between the rafters. Position blocking so an edge of the ceiling lining will sit along the centre of the blocking. Cut blocking and nail in position so it is in a straight line. Before fitting last blocking piece, run a stringline along the end rafter to ensure it is straight, cutting the blocking to suit.
Run metal strapping diagonally across the top of rafters to brace the structure. Nail at each end then use tensioning clips to make it tight. Nail through strapping into rafters using timber connector nails.
At junction between rafters and the wall plate and beam, attach Multi-Grip connectors, nailing into both members with connector nails.
Roll out sarking across top of rafters. Start at bottom of roof, allowing the sarking to overhang the outside of the posts by about 70mm. Hold sarking in place using foil clips. Work your way up the roof, overlapping the sarking as you go.
Cut fascia to fit along front and side of pergola. Cut on a 45-degree angle at the corners to form a mitred join and to width so it will overhang the bottom of the beam by 20mm. Where the fascia spans between the posts, nail blocks to the beam to provide something solid to nail the fascia to.
Along fascia use a chalkline to mark out for the bottom of the gutter brackets. Make the gutter fall a minimum of 2mm for every metre of length, although a little more is better. Nail brackets to fascia with flat heads nails, spacing them about a metre apart.
Fix stop ends to gutter using pop rivets. Drill holes for rivets through the gutter into the stop ends then insert rivets and tighten using a pop rivet gun. Smear silicone around the inside of the gutter to seal the join.
Cut hole for the downpipe outlet in the bottom of the gutter near the downhill end. Sit the outlet upside down on the inside of the gutter and trace the inside of the outlet on it. Drill a large hole to allow access for your tinsnips, then cut out. Sit outlet inside then pop rivet and silicone as you did for the stop end.
Sit gutter inside brackets on fascia. Bend spigots on top of the brackets down over the gutter to hold it in place.
Using wide vice grips, bend up the back end of the trays in the roofing to stop water overflowing the top edge of the roofing.
Lift roofing onto pergola so it overhangs into gutter by 50mm and is square to pergola. Screw through ribs of roofing into beam and rows of blocking between the rafters using roofing screws.
Measure up roof for barge capping to cover the join where the roofing meets the side of the pergola and also flashings that will cover the join where the roofing meets the house to prevent water entry there. Have these elements fabricated by your roofing supplier. Screw through capping and flashing into ribs of roofing and silicone where these elements meet to prevent water entry.
Have your electrician run cables for the lighting and any other electrical elements.
Using a hired panel lifter, lift ceiling sheets into position on underside of rafters. Screw sheets in place using fibre cement screws. To cut sheets to fit, use an angle grinder fitted with a diamond cutting blade or a circular saw with a fibre cement cutting blade. Make sure you wear a dust mask while doing this.
Fill gaps around your pergola with an acrylic gap filler. Fill nail holes using an exterior wood putty and sand smooth. Apply 2 coats of exterior paint to pergola and ceiling, allowing it to dry after each coat.
Get your electrician back to install light fittings.
For more incredible projects, gardening ideas and DIYs, pick up a copy of the latest issue of Better Homes and Gardens magazine in selected newsagents and supermarkets or buy online today!
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