Imagine you’ve bought your sloping block, picked your builder, and started digging. But then you hit rock.

It’s not in the plans, and your builder didn’t flag it earlier because they didn’t bother with proper soil tests. Suddenly, the costs for excavation are through the roof, and your builder tells you the only option is redesigning your home to build up instead of cutting into the land.

And that’s not the end of it.

The retaining walls, meant to stabilise your site, weren’t designed to handle the slope, so they start failing under pressure. What’s more, water runoff begins pooling in places it shouldn’t, eroding the soil and threatening your foundations. Fixing these mistakes means ripping out already completed work, redrafting plans, and pushing back your timeline.

And all the while, you’re watching your budget spiral out of control, wondering if this nightmare will ever end.

Building on a Sloping Block Isn’t Your Typical Project

It comes with a heap of challenges — design headaches, unexpected costs, and the risk of budget-blowing mistakes. You can’t just plonk a cookie-cutter design on a tricky site and hope for the best.

But there’s a silver lining.

Sloping blocks are actually opportunities in disguise — a chance to make the most of your land’s natural features and build something truly unique. You just need a little know-how and a proper plan.

Here’s what Perth builders who specialise in sloping blocks do differently:

Approach #1: They Start With the Groundwork

It all begins with what’s under the surface. Quality builders get soil tests and surveys done to check for things like rocks, clay-heavy soil, or unstable ground. Then they adjust the build as necessary. For example, hitting rocky areas early might lead to you using a raised foundation rather than cutting into the rock, which can save time and thousands of dollars.

And then, on clay-heavy soils, a builder might prioritise lightweight construction methods to reduce shifting in the foundation over time. Without this, you could end up with uneven floors or cracked walls — costly issues to fix after your home is finished.

Approach #2: They Use Custom Designs That Work With Your Block

With a sloping block, it’s best not to use designs that fight an uphill battle against the land (pun intended).

Split-level homes are a great example of this. Instead of trying to flatten the block entirely, the split design allows for different levels to follow the land’s contours. This not only reduces the need for expensive retaining walls but also creates unique, functional spaces.

You could separate living and sleeping areas across levels for added privacy, create a lower-level entertaining area that flows seamlessly into the outdoors, or capitalise on a great view from an elevated deck.

Approach #3: They Get Your Services in the Right Spot

On a sloping block, the location of things like bathrooms, kitchens, and garages makes a massive difference.

Placing your toilets and plumbing features so they work efficiently with the natural fall of the land is a critical consideration. On a flat block, plumbing can run in multiple directions, but with a slope, the design has to account for gravity to avoid costly workarounds.

Another thing you might need to consider is putting your garage on the high side of the block, as this can cut down on excavation costs and make street access a breeze.

Approach #4: They Sort Out Drainage and Stormwater Early

Poor drainage is one of the biggest risks on sloping blocks, but good builders get it right from the get-go.

Tiered retaining walls can stabilise the site, while, on steeper blocks, gravel trenches and drainage pits can keep water from pooling or causing damage to your foundations. Another effective solution is installing surface drainage channels along driveways or paved areas to direct water away from your home.

These solutions don’t just protect your property; they also open up landscaping opportunities, like gardens and terraces, that add character to your outdoor areas.

Approach #5: They Prepare for Access Upfront

On a sloping block, managing materials and trades can quickly turn into a circus if you haven’t planned for easy access.

Scaffolding is key here — used to create stable, level working platforms at every stage of the build, from laying the foundations to finishing the roof. Without it, things can grind to a halt or become unnecessarily dangerous.

A good builder will also work out how to get machinery onto the site without blowing the budget on big earthworks. Sometimes that means using smaller, more specialised gear to get the job done.

It might sound simple, but this kind of planning is what keeps the project running smoothly and your costs under control.

The Bottom Line: Sloping Blocks Aren’t for Everyone

They’re typically more complicated and costly than flat builds. But with the right team behind you, they’re worth the effort: you can turn even the steepest block into a home that’s beautiful, practical, and completely your own.

But there’s more to building a custom home in Perth than working with (instead of against) a sloping block — which is why we’ve put together this free guide for you to download:

Build with Confidence – 7 Things You Must Know Before Designing a New Home

It’s packed with practical advice to help you steer clear of homebuilding pitfalls and build a home you’ll love.