For many people, a sloping block can be a desirable piece of land. It can often mean superior views and natural light, good separation from neighbours and opportunities for creative house design that may not be possible on a flat site.
However, it’s not without its challenges. Designing a home and building on a sloping site can be more complex and expensive than building on a flat piece of land and there is a lot to consider if you want to avoid budget blowouts.
Most sloping blocks will require an experienced custom home builder to design and build a house that is suited to the site. But it can often be worth the hassle, with elevated properties tending to appreciate more in value over time.
So let’s have a look at what you’ll need to consider if you’re thinking about building on a sloping block.
Sloping Site Analysis
A site and soil analysis is important when designing and planning any building. But it’s doubly important for a sloping site. Sloping ground can give rise to a whole host of potential issues from drainage problems and flooding to soil slippage and erosion.
A comprehensive site analysis will help the designer or architect work out how to best design the building to suit the slope and determine what type of site preparation is required.
A qualified geotechnical engineer should also perform a soil test to determine the stability of the ground and the soil type, as well as any issues with drainage, water table and tree roots.
A comprehensive site analysis will help to identify any potential issues, mitigate any ongoing concerns or risks and ensure the building is suited to the land and its specific requirements.
Orientation is important for any home. It will determine the building’s exposure to the sun and wind and have a significant effect on your home’s energy efficiency and liveability.
However, when building on a slope, you may have fewer options regarding the orientation of your home. The orientation of the slope itself may determine the extent to which your home will get exposed to the sun and wind and this will need to be factored in at the design stage.
Direction and Grade of the Slope
A sloping site can slope upwards from the road below or downwards from the road above. Whether it’s an upslope or a downslope will determine a range of factors including the amount of site preparation required, the design of the house and potential site access issues.
The severity of the gradient (i.e. how steep the slope is) will also affect the design and construction of the building. Ensure you have a surveyor carry out a full contour survey to assess the topography of the land. This is vital to determine the stability of the slope and assess for potential hazards like landslides and erosion.
A sloping site can add complexity to drainage issues. It can increase stormwater runoff and the risk of erosion. If your site slopes to the rear, you may need to look into pumping systems or stormwater pits to deal with the excess water.
A sloped site can also affect the sewerage requirements. If the sewerage system is uphill from the building, it may require a pumping system. If it’s downhill, it may need a slow-flow system installed.
Ensure that adequate drainage precautions are factored in at the design and construction stage, as it can be difficult and costly to fix this once construction is complete.
A sloping block can present access problems when it comes to construction and materials delivery. This could affect the complexity of construction and increase construction and delivery costs.
Sloping sites generally require much more site preparation than flat sites. This could include significant cut and fill work, retaining walls, complex foundation laying and stilt placement. Properly preparing a site can be expensive and time-consuming so be prepared for this at the beginning.
Landscaping a block with a steep gradient can also be tricky and costly. It may require terraces or retaining walls, which can add another significant lost layer on top of construction. Additionally, not all plants are suited to sloping surfaces and any major root systems have the potential to shift the ground.
Choose an Experienced Builder or Architect
If you’re looking to build on a sloping block, the best thing you can do is find a builder or architect with experience working on sloping sites. Ask about any sloping block projects they’ve worked on and what were the major challenges they faced. Discuss creative design options that will make the most of the sloping block, like split-level houses or building on stilts.
Be aware that volume builders tend to design homes that are suited to flat sites and may charge much more for a custom design for a sloping block. A good custom home builder, however, should have extensive experience designing and building on slopes and shouldn’t charge much more to work on a sloping site.