Building on a Sloping Block: Costs and Considerations

Building on a sloping block can give you better views, more natural light and a home with real character. It can also add costs that don’t show up in the land price. Here’s what we look at when clients bring us a sloping block anywhere across the Gold Coast and Brisbane, from Coomera and Pimpama through to the hinterland.

Why a sloping block is often cheaper to buy

Some land developers cut and bench sloping land before selling it as flat lots, building the retaining walls themselves. You avoid extra site works, but you pay for that preparation in a higher land price.

Other developers keep the natural fall of the land. The block is cheaper to buy, but the cost of making it buildable moves to you, so it pays to understand what’s involved before you sign a land contract.

The main costs of building on a sloping block

Site works and excavation. Excavation is usually the biggest extra cost on a sloping block and can exceed $20,000, depending on how steep the land is. On very steep sites, a pole home or a stumped (suspended) floor may suit better than cutting into the slope, though these options come with their own costs.

Retaining walls. Once the building pad is cut and filled, it needs to be retained. Timber walls are cheaper and quicker to install but have a shorter life. Rock and concrete sleeper walls last longer but cost significantly more, and on a larger site can also exceed $20,000.

Soil tests and engineering. A soil test is essential on any block, and a sloping block may need deeper footings or extra underpinning where there’s fill. We often recommend a slope stability report from an engineer, which typically adds $500 to $1,500 depending on the site.

Site access. Machinery, delivery trucks and sometimes a crane all need a way onto the site. Planning access early avoids delays and surprise costs once construction starts.

How design keeps sloping block costs down

The key to keeping costs under control is to reduce earthworks and the amount of engineered retaining. The best way to do that is a home designed to work with the land rather than against it. A split level home design, for example, steps down the slope and can reduce excavation and retaining considerably.

The right design depends on which way your block falls:

• Sloping up: the low point is at the road.
• Sloping down: the high point is at the road.
• Cross fall: the land falls from one side to the other.
• Cross fall and sloping: a combination of the above.

Talk to a builder with sloping block experience

When you’re considering a sloping block, we visit the site, assess the fall, access and soil, and work with you on a clear brief and budget. Because every home we build is Built To Requirement™, the design is shaped around your block from the start, which helps avoid unexpected costs later.

If you’ve bought, or are thinking about buying, a block with a rise, fall or cross fall, talk to a builder with its own design team before you commit. We have designed and built many homes on sloping blocks, and our complimentary Core Feasibility Assessment is a good place to start.