How to build a timber pergola

Pergolas are an open outdoor structure made up of wooden posts and have a framed roof either open or covered. They were common features of 17th-century Italian gardens, often covering walkways and today, the same design is used to frame a focal point in your garden.

Pergolas are fast becoming Australia's favourite versatile outdoor structures; they can be built against the house or freestanding.Without solid walls or roof, a pergola defines an outdoor space by placing you both inside and out at the same time.

With the right design and consideration, you can create a beautiful, functional space for the Australian Summer where you can relax and socialise.


Pergola Materials

Timber is the most frequently used material for such a project; the timber category can be subdivided into the various types that may be used - some of which are better for outdoor conditions than others. 

·         Treated softwood can be used for posts and beams

·         Hardwoods are more strength and weather attractively to look especially good with older houses.

·         Recycled hardwood timber is a useful alternative to freshly sawn timber


Pergola Design


A pergola in it’s purest form is four posts and some roofing beams, but there is a range of ways to create a unique look by adding rafters and slats or battens.

Since the space in the backyard often defines the pergola dimensions, there's no rule of thumb on length and width.

Other tips:

·         Don't anchor the structure directly to the existing stone patio. Dig footings to secure the posts.

·         Fixing a pergola to a deck can be dangerous, make sure your plans are engineered and structurally safe.

·         Local laws require setbacks from a property line so take this into account during your design stage.


Council Permission

Building any structure on your property requires council approval.Speak with your local council, as the laws surrounding pergola structures vary between areas.

While regulations vary, as a general rule, you should contact the council if:

·         Your pergola will cover more than 10 square metres of floor area (depending on your local laws)

·         Your planned pergola will include a wall enclosure higher than 1.4 metres

·         The floor will be 60cm plus above ground level

·         The pergola will be located less than 90cm from an adjoining property

·         Your pergola is going to be attached to your home

Contact your local council first and find out what local regulations apply. Once you know, you may be able to redesign your pergola and avoid the necessity for council approval

Pergola Costs

Pergolas can be economical to build, but the larger and more complex the structure, the more it is going to cost.

The costs of a pergola can range from $1,000 to $5,000 and upwards depending on many factors including the materials used for the structure and flooring, whether its DIY or professionally contracted, and contextual elements such as whether it is freestanding or attached to the house.


How to Build a Pergola

This is an overview of the basic steps of a pergola building process. For a more comprehensive DIY guide check out Bunnings’ DIY Video.

Contact local utility companies before you dig

·         You’ll have to dig holes which could damage pipes or power lines

·         Find the phone numbers for your utility companies or contact Dial Before You Dig which started here in WA

·         Call and ask about any pipes or lines that may be running underground

Install the Pergola Posts

·         Measure and mark an appropriately sized square

·         Dig postholes in the marked corners

·         Tip the posts up or place stirrups into the holes

·         Support the posts or stirrups making then straight and level

·         Pour in concrete

·         Cut the tops of the posts to the required height

Attach cross beams

·         Cut the crossbeams to length according to your plans and trim the ends 

·         Make sure the beams are level

·         Fasten them to the posts

Lay rafters across the cross beams

·         Lay the rafters perpendicular across the top of your cross beams

·         You can add more rafters and space them closer together, or add fewer rafters and space them further apart for more or less shade

·         Fasten them to the cross beams

Lattice panels

·    You can apply optional lattice panels to the sides of a pergola to create more privacy or provide a grid for climbing plants

Apply a Finish

·         Paint or stain to finish your pergola for colour

·         Create an even, weathered appearance with a water-based timber treatment

·         Attached a shade cloth to add more sun protection

·         Grow a climbing plant such as wisteria for shade and colour


Enjoy your beautiful, functional space created by your garden pergola immediately once it's up in time for the Australian Summer.

Austim is the leading timber supplier Perth goes to for all their timber solutions, we offer a complete timber resource for all your building needs.

Contact us online or by phone at (08) 6558 1266.

Mike Rowney