DIY – $4250 (Have it done for $7120)
Skill – 7/10
Time – 8 days
A pergola provides the ultimate in backyard relaxation during summer, especially in a sunny backyard. They provide shade from the hot summer sun when covered with bamboo or a shade cloth, and in winter the covering can be removed to allow sun to stream through.
This sunny poolside had a bare patch of ground adjacent to the paving, so a pergola was built above a freestanding deck to create a stunning resort-style relaxation area.
Seven 90 x 90mm posts support the pergola, with the existing shed corner post serving as the eighth, front right post. Four back posts support the rear beam.
Rafters span the beams, with battens fixed perpendicular to the rafters to support the bamboo roofing.
Preparing the site
Measure and peg out the deck area, removing vegetation and debris. The pergola post setout was measured from the corner of the existing shed, along the angled pool paving header course, with a post positioned on the change of angle so the shape of the deck matched the paving.
Set stringlines for the back and centre-lines of the stump posts, marking post positions with pegs.
Excavate the holes to 400mm-square and 600mm-deep using a posthole digger if the ground is soft, or hire a powered auger.
Concrete can be mixed on site using a ratio of four parts aggregate (gravel), two parts fine-grain sand and one part cement. Set the posts in concrete with 100mm of gravel for drainage. Concrete the deck stumps when the pergola is finished.
Building the deck
The raised merbau deck is positioned adjacent to the existing paving. Bearers are secured to the posts clear of the ground, creating a step up.
The deck is set on 140 x 45mm treated-pine bearers and 90 x 45mm joists, with bearers supported by 90 x 90mm pergola posts and a central row of 100 x 100mm stumps equally spaced between pergola posts to support the intermediate bearers.