When building a new sloped driveway for your home or business, you’ll need to meet the design regulations of your council. This can include, width, length, and importantly for properties on a hill, the slope of your driveway.
Slope driveways can cause a multitude of problems for vehicles and for your property. These include poor drainage and water damage to the infrastructure, damage to vehicles as they risk ‘bottoming out,’ and causing your vehicle to lose grip in wet weather.
However, it’s not all bad news for properties on hills – there are a few ways to reduce the issues associated with sloping driveways, meet the Australian standards for driveway gradients, and still have a stylish driveway your neighbours will envy.
The Australian Standards for Sloped Driveways
In Western Australia, Main Roads WA recommends sloped driveways should have a maximum grade of 5-8% for commercial vehicles to climb the slope without risking damage.
For cars, the maximum recommended grade is 10-15% or 1:10 to 1:7 for gradients. Main Roads WA also recommend the maximum change of grade along a driveway is 12.5% to prevent the bottoms of vehicles from scraping on the sharp slope.
In Victoria, the maximum driveway grade is 20% or a gradient of 1:4, according to the Victorian Planning Authority. The same maximum grade applies in New South Wales, with transition gradients required when a change in grade exceeds 12.5% or a gradient of 1:8. Brisbane City Council allows for a gradient of 1:4 inside the property line and 1:6 outside the property line. The rate of change can be a maximum of 1:12 for a minimum of one metre.
However, each council has its own rules and regulations, so it’s important to ensure your plans for your new sloped driveway are comply with those limits.
Sloped Driveway Gradient Calculator
To find out your sloped driveway’s gradient, see our driveway gradient calculator.
Reducing the Slope of Your Driveway
There are a few design ideas you can incorporate into the plans for your new driveway if you are worried about the grade of the slope.
Zig-zagging your driveway, rather than allowing it to run straight up and down, will reduce the gradient by adding length. The long driveway will incline gradually, which means your vehicle won’t risk ‘bottoming out’ on sharp gradients. It will also help with water dispersal, which coupled with additional drainage, will prevent damage to the driveway.
Cars are often fine once they’re on the driveway but can risk ‘bottoming out’ if the gradient going entering or exiting the driveway is too steep. Transition gradients are a great way to smooth out sharp gradients and prevent your car from scraping. Transition gradients are constructed at the top and bottom of your driveway to reduce the change in grade to less than 12% by transitioning out of the gradient in two or more stages.
Curving your driveway is another solution to reducing the steepness of the slope. The idea is to allow vehicles to enter and exit at an angle, reducing the gradient compared to when driving straight up or down.
Another solution involves installing turnaround bays near your property so you don’t need to reverse down the sloped driveway, as this can affect your visibility. Going down the slope forwards will also help you control your speed.
Kerbing can ensure your vehicle stays on the driveway and help guide you up or down the slope. It will also help protect any garden beds by creating a barrier to prevent any debris spreading onto your driveway. Aside from the practical benefits, kerbing can also add to the aesthetic appeal of your drive by creating clean lines and creating a well-organised look.
Finally, you may want to consider installing drainage to help direct any stormwater back into the soil and away from a building or neighbouring property. Soakwells are a great way to confine water run-off to your property, in line with the laws in Western Australia. They are underground tanks made from durable materials which catch and disperse stormwater into the surrounding soil. Driveway drains and soakwells will help prevent water damage to your driveway, reducing the level of maintenance required.
Using Asphalt on to Construct Sloped Driveways
The most popular materials used in driveway construction are concrete, paving or bricks, asphalt, and gravel, limestone and roadbase. However, when it comes to constructing a sloped driveway, the material you choose can have a big impact on the ease of traversing the gradient for vehicles, and the amount of ongoing maintenance that may be required.
Concrete can result in a loss of grip for vehicles, particularly during wet weather, due to its smooth surface.
Gravel, limestone and roadbase are a cost-effective choice, however, they are at risk of becoming loose under traffic. This can result in rutted and uneven surfaces that need repairing, as well as a reduced grip on vehicles traversing the driveway.
Pavement and bricks are prone to spreading and movement over time, plus they can be costly when it comes to long or large driveway.
Asphalt is both cost-effective and durable, it is a suitable material for large driveways and will require less maintenance in the long run. However, it can only be used on slopes of less than 10 degrees, or a gradient of 1:6 with a grade of 17%, as it can be difficult to lay and compact. Since your driveway shouldn’t have any grades of above 15%, asphalt is a viable choice.
This material is known for its ability to withstand traffic from heavy vehicles, resist water damage, and adapt to changing temperatures without cracking, so it is suitable to Perth’s climate.
Not only that, but asphalt’s granular nature makes it easy to repair as the damage can generally be swept out and resurfaced.
Another benefit of using asphalt is its ability to ‘cure’ quickly. You can use your asphalt driveway within hours of construction, rather than requiring weeks to solidify like other materials. This can have a huge impact on the accessibility of your home or business.
If you are looking to build a sloped driveway in Perth, the hills, or a nearby rural area, speak to our driveway experts for a free measure and quote. At NK Asphalt, we offer free advice and can visit your property to provide recommendations on a sloped driveway solution.
If you have any questions, don’t hesitate to speak to our team.
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