What to consider before building an outdoor structure

Raise the roof

With summer on its way, you might be looking to expand your home's horizons with a pergola, verandah or carport. While most structures need planning permission, councils and state legislation have, in recent years, allowed some to be exempt, meaning you can get on with the job without having to lodge a development application.

Speak to your local planning officer

To make sure you're doing the right thing, speak to a planning officer at your local council, who can advise whether you'll need plans and a certifier. In NSW, for example, you can build a carport, balcony, deck or pergola without planning permission if it meets certain criteria relating to floor size, wall and roof height, and distance from a boundary.

It's important to do your research to avoid getting caught out, as structures built without permission, that are later found to have needed it, can be subject to fines and even demolished. Ignorance of the rules is no defence! Be aware that even D.I.Y. kit-set pergolas may sometimes require a building permit – if you're in any doubt, ask first. Even if your potential project is an exempt development, you still need to do your due diligence by checking the location of all your services – water, gas, sewerage and power – before you dig any footings. Consult Dial Before You Dig.

Safety first

While they might seem like simple structures, decks and pergolas are serious business. If your deck is more than 500mm above ground level, licensed builder John Davis of Open Plan Living suggests that you consult a structural engineer for advice. “Decks and balconies carry live loads – that's people moving, and potentially dancing, which means they need to be structurally safe and sound,” he says. “Far better to spend the money on an engineer's advice than risk a collapse that could cause injury or even death.”

Decking specialist, Greg Candrick of Precision Decking agrees that expert advice is worth seeking. “The national construction code changed recently and I'd recommend that anyone planning to attach a deck or balcony to the house get advice from a builder or structural engineer.”

Blowin' in the wind

A roofed structure will also need to take into account the effect of wind on the building. The wind load will vary depending on where you live, and this information will inform what type of tie downs you'll need for the structure.

You'll also need to check the product specification of your roofing material and fasteners to ensure correct installation and fastening – this ensures safety and efficacy of the product. A structural engineer can help you with this and advise on what's needed, as well as advise you on the size of all framing members and footings specifications.

Check out our guide before you get started

See our video series on how to build a pergola to check out what is involved in the build as well as simple steps to follow. 

Even structures that don't require approval still need to comply with the Building Code of Australia and if you're in a bushfire-prone area, you'll need to be especially careful selecting materials. Softened by climbing vines, a pergola can define and shade an alfresco eating area and add rustic charm.

Photo credit: Photography Gap Interiors/Devis Bionaz and Larnie Nicholson