Two cars, one driveway, and a post right where the passenger door swings. You’ve probably done the shuffle. Open, squeeze, close, shuffle along. Or you’ve watched someone clip a corner post on the way in and said nothing.
A double cantilever is a carport that covers two vehicles with its roof held up from one side only, so the parking area stays free of posts. According to Prestige Carports (2026), that layout suits sites where four posts would shrink the parking space or block traffic flow. Cost and rules depend on the span.
If you’re already comparing options, our double cantilever page shows the design and our gallery shows finished jobs. This article covers what drives the price, how big it needs to be, and one rule most people miss.
What is a double cantilever carport?
Quick definitions first. A cantilever is a beam or roof fixed at one end and unsupported at the other. A double cantilever carport refers to a cantilever roof wide enough for two vehicles, held by posts on a single side or along one line. A span is the distance the roof reaches across without support underneath. Footings are the concrete bases the posts sit in.
That last one matters more than it sounds. With no posts on the far side, the footings and posts do all the work holding the roof up and resisting wind. Prestige Carports (2026) says projects can include structural calculations, footing specifications and certified plans, and that local wind classifications can shape the final design.
How big does a double carport need to be?
Bigger than people think. According to Fair Dinkum Builds (2023), a standard double carport is about 6m wide and 6m long, with a minimum height of 2.4m. Utes and 4WDs often need 6.5m to 7m in width, and long utes may need 7m to 8m in length.
Here’s why that width exists. The same source says doors need roughly 600mm to open fully, and it suggests about 400mm to 500mm of clearance per side if you’re loading kids or shopping.
Height is the other trap. For a 4WD, van, caravan or boat, the guide suggests 3m to 3.6m or more. Measure your tallest vehicle with the roof rack on, not off.
What affects the cost?
The site doesn’t publish prices, and neither will I, because a number without your block is a guess. Here’s what moves the quote, based on the factors Prestige Carports lists on its double cantilever page:
| Cost factor | Why it moves the price |
| Span | A wider reach needs heavier posts and stronger footings |
| Roof design | Shape, colour and drainage all change the build |
| Post configuration | Position and number of posts affect the engineering |
| Footing depth | Soil type and ground levels decide how deep |
| Material grade and finish | Coastal grade materials and powder coating cost more |
| Site access | Tight driveways and slopes add labour |
| Approvals | Council approval or certification adds a cost |
Ask for the quote to be itemised, with timeframes written in. Prestige Carports says its quotes are itemised, and that’s the standard to hold any builder to.
Design choices that matter
Post position first. You can usually choose where the support sits, so put it where it won’t block a door, a gate or a turning circle. Mark it on the ground before you sign off.
Then the roof. The company lists polycarbonate for filtered light and steel for full shade, with optional gutters and downpipes. Think about which you’d rather live with in a Sydney summer.
Materials come next. The company lists powder coated steel, aluminium components and reinforced footings, and says its aluminium frames are marine grade for coastal sites. Near the water, ask what’s used. Our aluminium carports page covers that side, and the double aluminium carports page covers the twin car version. If you only need one bay, see single and multi space carports.
The rule most people miss
A double carport is large, and size triggers rules. According to the NSW Department of Planning and Environment (2022), carports built as exempt development are capped at 20 m² on lots of 300 m² or less, and 25 m² on most other lots over 300 m². Rural zones and R5 get 50 m².
Now do the sums. A 6m by 6m double carport is 36 m². On a standard suburban block, that’s over the exempt limit. So you may need a development application or a complying development certificate instead. How your council measures the area can differ, so confirm before you spend a cent.
The same document adds a 3m height limit, at least two open sides, a front setback of at least 1m and side and rear setbacks of at least 900mm in most zones. Heritage items and foreshore areas are excluded. The document dates from January 2022, so check the current rules with your council or a certifier.
Prestige Carports says it handles council approvals and technical drawings. Ask what that covers on your job.
Questions to ask before you sign
- Is the price itemised, with footings and engineering included?
- Who handles the approval, and are certified plans supplied?
- What span and wind rating is the design built for?
- What roofing and finish do you recommend for my site?
- How long will the build take once approved?
- What happens after installation if something’s wrong?
That last one deserves attention. The company’s site mentions seven days of post installation support, but it also states no warranty terms. Get any warranty in writing.
The mistake that costs twice
Sizing for the cars you have today. A 6m wide carport fits two sedans. It won’t fit the 4WD you buy next year. Add 500mm of width now and save a rebuild later.
My view: plan around the biggest vehicle you might own in five years, then check the approval rules before you fall in love with the drawing.
FAQ
What is a double cantilever carport?
A double cantilever carport covers two vehicles with a roof held up from one side, so the parking area has no posts. It suits tight sites where four posts would get in the way.
How big is a double carport?
According to Fair Dinkum Builds (2023), about 6m by 6m is standard, with a 2.4m minimum height. Utes and 4WDs often need 6.5m to 7m wide.
Do I need council approval for a double carport in NSW?
Often yes. According to the NSW Department of Planning and Environment (2022), exempt carports are capped at 25 m² on most lots over 300 m². A 6m by 6m carport is 36 m², so check with your council.
How much does a double cantilever carport cost?
It depends on span, roof, post setup, footings, materials and approvals. The site doesn’t publish prices, so request an itemised quote.
How do I get a quote?
Call 02 9522 6395, email prestigecarports@outlook.com, or use the quote form on the website.
Ready to plan yours? Contact Prestige Carports at 7 Old Taren Point Rd, Taren Point NSW 2229. See finished work in the gallery, explore carport kits in Sydney, or read about cantilever carports in Sydney on the home page.
