Building on a sloping block – Everything you need to know!

by | Feb 7, 2023 | Advice & inspiration, Building basics & regulations, Building tips

When looking at building on sloping land, you may be wondering what challenges this will present compared to a flat block. The good news is that there are plenty of beautiful homes built on uneven terrain, especially in the Brisbane area. Having said that, there are things you need to be aware of before you get started. This article is all about building on sloping blocks including:

  • What counts as a sloping block?
  • The preparation and due diligence you’ll need to carry out.
  • Your options are from building on stilts and levelling out land to split-level homes.
  • How Buildi can help you on your building journey, no matter how steep the slopes.

What defines a “sloping block”?

A sloping block is a lot of land with uneven levels of elevation, resulting in there being a slope from one side of the block. Basically, if your block isn’t flat, it will be classified as a sloping block. A quick drive around Brisbane will show you this isn’t an uncommon thing at all. Whether it’s a steep or gradual slope across the entire block or just a part of the land, understanding the building area helps with both the design and construction costs and process.

What is a sloping site analysis and why is it necessary?

A sloping site analysis is an essential part of building on a sloping block as it’ll provide vital information about the physical characteristics of your land. Not performing a site analysis is the equivalent of walking in the dark, as you and your builder won’t know the potential issues. By preforming these steps, they can confidently tackle your projects and plan to suit the conditions.

Site preparation, including surveys and soil tests, is an important step, regardless of how steep your property is. No two blocks of land are the same and performing your due diligence provides your builder with a detailed understanding of your land, which in turn means your house can be well-designed and built. It’s especially important with more challenging blocks, such as sloping blocks.

What will a sloping site analysis include?

Now that we know what a site analysis is in a general sense, let’s dive into the nitty-gritty and look at exactly what the process includes. Below is the type of information being sought during a site analysis Depending on your block, certain factors will be more of a priority than others.

Severity of the sloping block of land

You can have a downward sloping block from the road and some slope upwards, each providing different design challenges. Having the specific angle of your sloping block helps with both design and construction. Steep slopes provide more of a challenge but aren’t impossible to work with.

Contour surveys & topography

Topography and contour surveys focus on the elevation and natural formations on your land. The survey determines where the contours are in your property, the steepness of your sloping block, and the location of any easements, trees, and vegetation. The resulting map that comes from this survey is invaluable to the building and designing process.

Soil testing & condition of the ground

A soil test is an important part of your performing your due diligence as it will help you determine the soil stability. The results of a soil test will reveal whether there are any chemical or physical conditions that could damage your home or cause issues with your foundation.

Climate and vegetation

A site analysis may need to consider any existing plant life and the climate. This will help you determine factors like solar orientation and wind direction, which in turn, help your builder design your home. A well-designed house will use the weather and conditions to its advantage. Whether trees will need to be removed is something you’ll need to discuss with your builder.

Drainage corridors

Understanding the natural drainage of your land is essential to understand because it determines how water will affect your property, whether there are any potential issues and how to avoid moisture build-up which can cause erosion. This information is particularly important if you’re building in an area prone to heavy rains. The information from the analysis will allow your builders to develop ways to create adequate drainage, including:

  • tanks
  • drainage corridors
  • stormwater pits
  • swales


Determining how people and vehicles will be able to easily access your property is an important factor to find out about sloping sites. This will help design your driveways and other entryways.

What are the most common home design solutions for building on a sloping block?

For as long as people have been building structures, they’ve had to deal with sloping land. So in that time, there have been a few home design solutions that have stood the test of time. Each design has its advantages, disadvantages, savings and additional costs involved. Your specific situation and block of land will play a major role in determining the best design for you.

Building on stilts

Stilts are a popular means of combating block slopes or hilly terrain. Stilts can be poles, posts or pillars used to create a building to stand a distance above the ground.

The classic Queenslander design uses stilts.

Pros of building on stilts

  • Can provide a more scenic view.
  • Better ventilated and offers better airflow
  • Can provide extra safety in flood-prone areas. It might even lower your flood insurance costs.
  • Less vulnerable to timber pest damage
  • Can increase the structural integrity of a home.
  • Depending on the height, you could have some extra storage space.

Cons of building on stilts

  • This can lead to thermal efficiency issues, which may lead to higher energy costs, depending on your climate.
  • Though great for South-East Queensland, there can be issues for homes up north or in cyclone-prone areas.
  • Depending on the design, you may have to use stairs which won’t be ideal for anyone with mobility issues.

Levelling a building site

Levelling a building site involves excavating land to create a flatter landscape to build on. By levelling out the land, you may be able to use more traditional home layouts.

Pros of levelling a building site

  • Might end up costing less, depending on the exact slope you’re working with.
  • Helps your home to blend into the surrounding area
  • Fully enclosed.
  • Allows you to use a floor plan that would also work on a flat piece of land

Cons of levelling a building site

  • Disturbs the natural ground, which can cause a range of difficulties from stability to drainage issues.
  • You may need large engineered retaining walls, which will add additional costs.
  • Excavation can be a roll of the dice, as it can be difficult to predict what effect the disturbance on the land can have. You may find boulders and deep tree roots that affect the natural ground-level sustainability.
  • Unforeseen issues can be very expensive, depending on the severity. Management is key, so be sure to hire a reliable evacuation company.

Building a split-level home

A split-level house design aims to work with the sloping block, and have multiple levels or staggered floors. Whereas a traditional multi-level house design will have at least two distinct storeys, a split-level home can have shorter levels (at least two or three), connected by short flights of stairs. Whether it will be a cheaper option will depend on your potential excavation costs.

Pros of split-level homes

  • Have a unique, pleasing aesthetic design that can increase your curb appeal when done well.
  • No need for retaining walls.
  • Avoid unnecessary excavation which is great for minimising construction costs.
  • Able to get more house area than you would with a single-storey home design. Smaller footprint leaves room for a swimming pool, a bigger backyard, or outdoor structures like sheds or pergolas.
  • Avoid long, steep, winding driveways.
  • Save money on excavation costs.

Cons of split-level homes

  • Indoor stairs are unavoidable in a split-level home.
  • Split-level homes provide a lot of design challenges, especially for any major renovations.
  • The unique characteristics are a double-edged sword that makes your home stand out but also an acquired taste.

How to choose the right builder for building on a sloping block?

A sloping block naturally provides more challenges than a flat block will, and therefore, your choice of builder is vital to the project being a success. We recommend searching for either a custom builder or a builder who specialises in difficult designs. These builders have more experience in building a home on a sloping block and understanding the physical characteristics of difficult terrain.

Looking for advice on building on sloping blocks?

Need a house built on a sloping block, but want to make sure you get the best builder for the job? We’re here to help! Buildi will take your project to our panel of builders and have them bid for your business. Once, you’ve chosen a builder, we can help you through the entire process, helping you communicate with contractors, ensuring you get everything you pay for, and helping you raise any concerns you may have. With Buildi on your side, you’ll have a smoother journey on the way to completing your dream home!

Book your free, impartial consultation today!


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Building a Home

Knockdown Rebuild

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Building a Home

Knockdown Rebuild

Home designs

Advice & inspiration