Knock Down rebuild on sloping blocks

by | May 16, 2024 | Knockdown rebuild

If you’ve ever driven around Brisbane and its surrounding suburbs, you’ll soon realise it’s not the flattest place in the world. While there certainly are flat blocks available, many of the city’s available properties are going to be on sloping blocks. With all that in mind, today’s question is, “Can you perform a knockdown rebuild on a sloping block?”

The answer is, barring some other factors, yes you can. Let’s delve into some of the unique characteristics of performing a knockdown rebuild on a sloping block of land.

Planning & design challenges of a knockdown rebuild on a sloping block

The biggest challenge that comes with any project on a sloping site is working with the decline of the land. Every part of the knockdown rebuild process from the foundation to the choice of house design will be need to accommodate this slope. Some potential challenges include:

  • Adjustments to a house design to help it suit your block.
  • This can make the job more challenging for the demolition crew.
  • More considerations when it comes to terrain

What is the demolition process of a knock down rebuild on a sloping block?

Site Preparation

Preparing your building site is essential before any construction can begin. This entails performing a soil test to test the ground conditions and provide an idea of the foundation. Soil tests are crucial to finding out key information and this site analysis will help your builder and play an important role in planning your build.

For steep slopes, a detailed contour survey is crucial to understanding the natural formations, as more careful consideration will be needed for foundation design than is required for a flat block.

Figure of the scope of the project

When looking for contractors, it will help if you can provide an accurate description of what you want. This not only helps you find better-suited tradespeople, but it also helps them come up with more accurate quotes, timelines and estimates for your project.

Finding and hiring a contractor

When it comes to finding the right contractor, it’s usually worth talking to a few different demolition companies. Getting a quote from each will allow you to compare and see what is available. Ask knockdown rebuild specialists if they’ve worked on a sloping block before (some builders even specialise in difficult sites).

Depending on your site, you may need to also find a contractor to remove trees and other plant life from your land. We’ve written an entire article about removing trees, so why not give it a read?

Site inspection and preparation

As mentioned above, site preparation is important. Along with testing soil and performing surveys, the demolition company will need to inspect your property so they can plan the knockdown. If you live in an older home, you should also have your house inspected for asbestos.

Disconnect power

Before demolition can begin, you’ll need to disconnect all power from your property. This is something you’re likely going to have to sort out yourself by contacting your energy supplier. You’ll need to keep in mind that this can take a couple of weeks so try to sort it out sooner rather than later.

Demolishing the house.

Now everything has been sorted, your house can finally be knocked down. This will take anywhere between a couple of days to a week, depending on the scope of the project. Meanwhile, you’ll need to find alternative accommodation.

Remove building materials, rubbish and debris.

When the demolition is complete, the debris and building materials will need to be removed. You may need to organise this yourself by contacting a waste removal company.

Begin your build

Now the existing home has been removed, you can commence construction on your new family home. This is a big enough step that we’ve written articles about the entire process. Click any of the links below to find out more about the construction process or the knock-down rebuild process.

How much does a knock down rebuild project cost on a sloping block?

Knock-down rebuilds tend to cost anywhere between $20,000-$40,000 for the demolition, plus the additional cost of the rebuild process. Because sloping blocks are more difficult, don’t be surprised if the quote comes in above average. There are a lot of factors to consider including:

  • The existing house design
  • The land quality includes soil condition, slope and overall terrain.
  • Your choice of new house design
  • The builder you hire
  • How complicated the build turns out to be.

What are some common issues we have seen with knock down rebuild project on sloping blocks & how to avoid them

Foundation work

With any sloping block design, creating a stable reliable foundation is key to the success of the whole project. A poor foundation can lead to structural damage that is expensive to fix at best and dangerous at worst. Depending on the soil condition, a structural engineer may need to be hired to help design a reliable base for your home.

Codes and Regulations

As well as making sure you comply with the National Building Code, you need to check in with your local council to ensure you’re following all guidelines.


One approach to sloping blocks is to flatten the land through excavation. Excavated soil can be rearranged or removed completely from the building area depending on what is needed.

Building on a sloping site? Here are a few articles you may find useful!

Our tips for knock down rebuild projects on sloping blocks

  • Site preparation and surveys are important on any block of land, but they’re especially important on a sloping block. Soil tests will help get an idea of the condition of your block while a contour survey will provide.
  • Consider thinking outside the box when it comes to designs. A split-level surface home can be a unique way to make the most of sloping blocks.
  • When talking to potential buildings, ask if they’ve worked on sloping blocks before. Some builders even specialise in challenging terrains.

Buildi is here to help you build your brand-new home. Book your free, impartial consultation today!


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Building a Home

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Building a Home

Knockdown Rebuild

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