Clarendon Homes Aussie Made and Owned - Knockdown Rebuild
Home Building / Knockdown Rebuild / 7 Star BASIX /26.06.23

Budgeting for your knockdown rebuild: understanding the costs involved

Clarendon Homes give you the peace of mind you need.


You’re thinking a knockdown rebuild is right for you because you can build your dream home in the suburb you love. But, you’ve heard the stories about builders hitting you with hidden costs after you’ve signed the contract. You want to make sure that doesn’t happen to you. That’s why it’s essential to choose a reputable builder, like Clarendon Homes, to give you the peace of mind you need.

In this article, you’ll learn the 4 main costs of a knockdown rebuild plus 3 extra costs you need to factor into your budget.



What are the 4 main costs of a knockdown rebuild?

Every knockdown rebuild is unique. It’s a complex process with many variables so there isn’t a one-size-fits-all price. This means it’s vital for you to get the expert guidance you need before you commit.

Here are the 4 main costs you need to understand:

Clarendon Homes Consultant stepping through the process
flexible floorplan options

1. Home Design

When you visit a Clarendon Homes display centre, your Sales Consultant will help you to choose the right home design, facade and floorplan for your block. 

If you have an initial budget in mind, your Sales Consultant will help you see what’s possible from our two ranges of home design – the Sapphire range and Aspire range.

Clarendon Homes offers many flexible floorplan options for every home design including butler’s pantry, alfresco areas, larger garages and extra living spaces so you can create the home you want.

You also have the option to choose from a range of upgrade packages to enhance your home even more with the guidance of your Sales Consultant. These are designed to save you money and give you upfront pricing.

Based on your selections and an overview of your block, your Sales Consultant will give you an initial estimate for your knockdown rebuild. This price is your base cost. At this stage, it doesn’t include all of your site costs because these must be thoroughly assessed in the next step of the process.

new knock down rebuild home by Clarendon Homes
before you commit

2. Tender Fee & Site Costs

To get an accurate assessment of your site costs, you’ll be asked to pay a Tender Fee. The Tender Fee includes your full site assessment, soil test, contour survey and a 10.7 certificate from the council (which shows the council requirements for your block).

These assessments and tests will determine the additional site requirements and costs for your block. This means you will have an accurate expectation of your site costs before you commit.

Additional site costs can include:

  • Traffic management and Work Zones if you live on a busy road
  • Tiger tails if you have low overhead powerlines or are building close to overhead powerlines
  • Rock can require specialised machinery which can substantially add to costs
  • Your soil type - acid sulphate or high salinity soil may require a higher specification of concrete
  • A sloping block could require drop edge beams and retaining walls
  • Tree removal and tree protection zones
  • Bushfire areas
  • Flood affected land
  • Areas without a good trade base can incur a traveling allowance as an incentive for trades
  • Acoustic requirements if you live near a flight path, busy road or train lines
  • A stormwater detention system may be required depending on your location and council


Your additional site costs will be added to your home base price and presented to you as a Tender Document. Your Tender Presenter will explain all of the costs and answer any questions you have. This means you will have a clear idea of your costs before you sign the building contract.

Knockdown rebuild progress Clarendon HOmes
compliance process

3. Council Requirements and Compliance

After you sign the Building Contract and pay a 5% deposit, your council application and compliance process will begin.

Your council application process will be completed as part of the building process. This could be a DA or CDC. 

You may also need to pay a Section 94 contribution depending on your council. Section 94 is an additional cost that can’t be avoided. Your Sales Consultant or Tender Presenter will explain how this works so you can get all of your questions answered.

Depending on your council compliance requirements, you may need to engage a specialist consultant which will add to your knockdown rebuild cost. This will be assessed during your initial site inspection.


If you do need a specialist consultant, you’ll receive expert advice from your Sales Consultant on when and how to engage the right type of consultant.

The most common types of specialist consultants include:

  • Arborists to assess established trees, tree protection zones and tree removal
  • Acoustic engineers for high noise areas eg. Aircraft, railway lines
  • Bushfire consultants
  • Landscape designer, if required for your council approvals
  • Hydraulic engineers for stormwater design and assessing flood levels


In addition, most councils require stormwater design. Clarendon Homes works with the hydraulic engineer to ensure this complies for your council.

Specialist consultants may also nominate additional building material requirements.

These can include:

  • Exposure grade materials for living near saltwater or lakes
  • New Stormwater infrastructure
  • Bushfire rated materials
  • Noise and acoustic materials

BASIX Requirements

Another additional cost to consider is the BASIX requirements for your home. BASIX stands for Building Sustainability Index and is the water and energy rating for your home. It must be included for your new home to be certified.

BASIX requirements are assessed after your building contract is signed and the requirements will vary depending on your block and council area. You’ll be guided through what all of this means for you.

BASIX can include:

  • Solar panels to offset electricity usage
  • Upgraded insulation
  • Taps that reduce water consumption
Home Design consultant with Clarendon Homes
internal & external finishes

4. Lifestyle upgrades for your new home

Your new home Tender Pricing can include allowances for standard inclusions. If you have the budget, you can choose to upgrade your lifestyle inclusions to a more luxurious specification.

These can include things like floor coverings, bathroom and kitchen upgrades and high-end appliances.

Your Lifestyle Studio Consultant will guide you and help you create your dream home within your budget.



What are the 3 extra costs you need to include in your budget?

These are important extra costs you need to consider for yourself because they aren’t part of the normal building process with most builders.

The main 3 extra costs you might not have thought of are:

Site domolition for a knock down rebuild Sydney
knockdown rebuild

1. Demolition of your existing home

Your existing home will need to be demolished to make way for your new home. 

Demolition costs are not included in your building contract price so you will need to allow for these costs when you’re budgeting for your knockdown rebuild.

It’s essential to choose an experienced demolisher who can help you through the entire demolition process including Demolition Approval and asbestos removal (if needed). It’s important to look at what’s included in the demolition rather than going for the cheapest price.

Clarendon Homes can recommend an experienced, licensed and insured demolisher. This will ensure that your site is left clear and ready to build on. 


Budgeting for your house build Clarendon Homes NSW
finishing your home

2. Landscaping & Driveways

Landscaping, driveways and fences aren’t included in your build so you’ll need to allow extra for this. Some councils require a landscape design for your council application. In this case, you can choose to engage your own landscaper or Clarendon Homes can organise this for you at an additional charge.

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Other costs to consider

3. Rental costs during your knockdown rebuild

You’ll need to move out while your home is being demolished and your new home built. This can take at least 12-18 months. Other costs you may want to consider are removalists and storage costs (if your furniture won’t fit it your rental property).

Unforeseen delays due to weather conditions and material shortages can also add to rental costs.

Your Site Manager or Customer Service Consultant will keep you up to date on the progress of your build so you can allow for any unforeseen delays as soon as they happen.

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Why choose Clarendon Homes for your Knockdown Rebuild?

The benefit of working with a reliable project home builder, like Clarendon Homes, is you get 45+ years of experience and a proven cost-effective process to guide you through your complete knockdown rebuild.

At Clarendon Homes, we aim to give you as many upfront costs as possible because you need to understand your budget before you commit. Integrity and transparency in pricing is part of our entire process.

Do you want answers to your knockdown rebuild questions?

Do you want expert advice and answers to all of your knock down rebuild budgeting questions? We’re here to help you.

Contact us today to get a free preliminary assessment from our experienced trained consultants