How to build a Pergola

How to build a pergola

Pergolas are one the best ways to extend the living area of your home adding valuable space. Pergolas can be ether flat or gable roofed and can be covered in metal or polycarbonate roofing. Flat roofed pergola are the easiest to build however pitched or gable roofed pergolas look the best.

Pergola design

As a general rule it is best to try to match the style of your pergola with the style of your house. For example: If the pitch of your house roof is 30 degrees then it looks the best if you mirror the same angle in your gable roof pergola. For more on pergola design.

Freestanding Pergola

Freestanding or Attached pergolas

Over the years I have built many pergolas of all shapes and sizes. The construction of a pergola is fairly straight forward with four main sections: Posts, bearers, rafters, and battens. All pergolas have these parts to them no matter the design or type.

Attached pergolas

Attached pergolas are connected to a house via the fascia board, wall, or roof brackets.

Pergola attached to the fascia board: This is by far the most common type of attached pergola with a whaler beam bolted to the fascia board and then bolted to the house roof rafters. Care must be taken to make a solid connection to the house. If you are attaching through a metal fascia you must use galvanised brackets or added timber at the back of the metal fascia to connect your pergola beam to the house. This is because a metal fascia cannot support any extra weight.
Pergola attached to a wall: This type fairly easy because you simple bolt your pergola beam (whaler beam) directly to the house wall. If you have a brick wall simply bolt into the brick (not mortar) using expanding masonry anchors. If you have a weather board or clad home you must bolt into the timber wall studs and not the cladding.
Pergola attached via roof stirrups: Roofing stirrups are not as common as the two types above however they are a great option. Some houses do not have a fascia and pergola roof stirrups allow the pergola to be build on top of the roofing material. The stirrups are attached directly to the house roof rafters and protrude through the roofing material with a waterproof boot or flashing and the pergola bearers can be attached to the stirrups.

Freestanding Pergolas

Freestanding pergolas are built using posts, bearers, rafters, and battens. However you will need extra bracing to stop the pergola from being blown over. The corner bracing locks each corner and stops the wind swaying the pergola which would result in the pergola falling down. Whether your pergola is a flat roof pergola or a gable roof pergola the construction of the posts and bearers is the same and both types must have corner bracing.

Building Your Pergola

Step one: Design your pergola

The first step in building a new pergola is to grab some pergola span tables and then check the size of the timber you will need compared to the size of pergola you intend to build. Then order your timber.

Step two: Pergola set out

Mark out your pergola with builders string and timber pegs. Mark and dig out the holes your posts. If you are attaching to a house prepare the house roof rafters with extra timber or galvanised brackets. Concrete in your galvanised metal stirrups ready for your posts. Wait until the concrete sets.

Step three: Install your posts and bearers

Installing pergola posts and beams

Once the concrete has set install your posts and brace them in place until you have your bearers in place and it is self supporting. If you are building a attached pergola install your whaler beam as well. However if you are building a gable roof pergola install all your posts and bearers. This is all fairly simple construction however for more detailed instructions and diagrams check out our full ‘how to build a pergola’ page.

Step four: Install your pergola rafters

Install your rafters to suit your pergola making sure they are fully nailed off and secure. For flat roof pergolas simply install your rafters on top or inside your bearers. However if you are building a gable roof pergola you will need to cut your rafters to the pitch or degree of your roof. For more detail on this check our building a gable roof pergola page.

Step five: Install your battens and finish off your pergola

Screw your battens down to the rafters at 900mm or 3 feet apart. Check over your pergola making sure that all your fitting are correct then paint and install your desired type of roofing.

This is the basics of building a pergola however if you would like to know more see renovation robot’s pergola building section – How to build a pergola.

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