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How Much Does a Knockdown Rebuild Cost?



There is a growing housing market trend in Australia: the knockdown rebuild. When a house is condemned for demolition due to unsafe structural damage, or simply when a new owner wishes to rebuild a home on a lot, but an existing home is in the way, this is called a knockdown rebuild.

These can vary greatly in project complexity, timelines, and price. Still, if you’ve come into a parcel of land through inheritance or are looking at purchasing land with an existing home on it and want a better idea of a knockdown rebuild cost, this guide is for you! 

What is a Knockdown Rebuild?

Knockdown rebuilds are a popular choice among new property owners who want a fresh start on their property. Sometimes, they bought a property because of the land it sat on, rather than the worn-down old dwelling that occupied it. In these cases, owners opt for a knockdown and rebuild option, rather than fixing up a ramshackle home.

In other cases, a disastrous fire has meant that a home is unsalvageable, and the cost of a knockdown and rebuild is cheaper than attempting to restore or selling the land and buying a new property elsewhere.

Landowners choose knockdown rebuilds for all kinds of reasons. In older cities, knockdown rebuild prices in Sydney are often cheaper than buying a newer home! Similarly, the knockdown rebuild cost in Melbourne (where a larger portion of older homes sit on valuable pieces of land) is often less than buying a more modern home through a mortgage.

Read on to learn how much it costs to knock down and rebuild a house and whether it’s the right option for your parcel of land.

What is the Average Cost of Rebuilding a House?

Suppose you’ve decided to rebuild your home after an accident of fate or simply an economical choice to purchase a low-cost plot with a house, knock down the existing structure and put your mark on the land. In that case, you’ll need to calculate the average cost to rebuild a house in Australia.

The first step in this process is demolishing your old home or the old existing structure. This isn’t something you can just do with 30 friends and some sledgehammers. You’ll need to call a professional demolition company. The average quote from most demolition companies is between $53 and $114 per square metre. The average size of an Australian home today is roughly 235 square metres, which puts the average cost to knock down a house at ~$20,000 -$25,000. Although this figure can vary greatly based on the complexity of the demolition.

Now, onto the rebuilding cost. This cost is around $1,900 per square metre, with the knockdown rebuild costs in Sydney rising to $2,500 per square metre. To help you better understand the cost of a knockdown and rebuild, here you’ll find a knockdown rebuild cost calculator, to help you factor in every possibility and see if a knockdown rebuild is the right avenue for your project.

Pros of a Knockdown Rebuild?

Creating Something New!

One of the many pros of a knockdown rebuild is that you’ll be able to create something fresh and new, your dream home, where an old, dilapidated building once stood. Like an artist, once you have a blank canvas to draw on, you’ll have full control over all building specifications, finishes, paints, colours, building materials and your new home’s interior and exterior look.

You can even go one step further and incorporate a whole new front garden into your rebuild if you want to! With a knockdown rebuild, the possibilities are endless.

Avoiding Hidden Problems With Existing Structure

There’s a possibility that you don’t really want to knock down the existing structure on your property. Perhaps you think it has character and can be salvaged, renovated and voila, a new home, and you may even save a few pennies. Unfortunately, this is often fallacious and is a bit like putting lipstick on a pig. There could be hidden structural, plumbing, heating, and roofing issues that you are blissfully unaware of. Unfortunately, over time, these issues may become catastrophic and could cost you far more to fix than to knock down and rebuild.


Building a new home after a knockdown rebuild means you can modernise it. Incorporate new technology like passive solar. These are solar panels on a brand-new roof structurally built to withstand their weight and low-flow toilets and showers with new plumbing designed to incorporate that type of device. In-floor heating with properly insulated walls and ceilings that keep heat in during the winter, while offering a pleasant temperate climate during the hotter summer months.

By absorbing the cost of rebuilding a home, you’re allowing yourself to recoup those costs in energy-savings, or resale value later. You also receive a new home warranty and everything is brand new, giving you peace of mind!

Increase in Property Value

While older homes have that character and charm, if they’ve been allowed to fall into disrepair, very few people will want to take on a make-work project like a fixer upper. However, a beautiful, newly built home will greatly increase the overall value of the property, should you wish to sell at a later date.

Cons of a Knockdown Rebuild?

It’s not all sunshine and rainbows when it comes to a knockdown rebuild, though. There are a few cons to this growing property trend.

Demolition Isn’t Always Fun

While few things bring more joy in life (to some people) than seeing things explode, demolishing a house isn’t about blowing it up with fireworks to boot. It’s a careful deconstruction process fraught with danger and hassles you didn’t expect.

For example, asbestos! It’s a fibrous mineral commonly found in older home construction that was commonplace during the last century. This stuff used to be everywhere until it was banned almost everywhere due to its cancer-causing components. If asbestos is found in your property during demolition, it must be professionally removed and not by your demolition company.

Environmental Impact

Unfortunately, the demolition process during a knockdown rebuild will produce negative environmental impacts. However, these are relatively minor (increased noise levels, increased diesel and petroleum output due to heavy machinery use). Still, it is in the disposal of waste product that the real environmental impact of knockdown rebuilds become apparent. Whatever demolition company you choose must have a clean environmental record and adopt best disposal practices when dealing with construction waste.

You don’t want to destroy the value of your land and home because your demolition company didn’t dispose of toxic waste properly.

4 Additional Costs That Apply to a Knockdown Rebuild?

Unfortunately, the cost of a knockdown and rebuild isn’t always obvious. Sure, the demolition and construction of the new dwelling are certainly apparent, but there are all sorts of hidden costs that you may not have calculated. Here are six of them.

Disconnecting Services

During your knockdown rebuild, you may encounter an issue where certain services need to be disconnected before demolition can continue or begin at all. Things like electricity and plumbing or natural gas lines. These all need to be disconnected before demolition begins by a qualified professional.

Additional Council Fees for Property Changes

You may incur additional charges from your local council for the specific changes you want to make to your property. For example, if you want to knock down an older falling-down second dwelling on your property and install a granny flat or second car garage, or even build a two-storey duplex where a single-storey building once stood, you are likely to incur significant council fees for zoning changes.

Foundational Changes & Footings

Footings are long, wide strips of concrete or rebar placed on the soil before any foundation is added to a new structure to prevent the structure from settling into the ground. If you notice that your existing structure is sinking into the earth a little, chances are these footings will need to be replaced. This is not an uncommon occurrence during knockdown rebuilds but can add to the knockdown and rebuild cost.

Alternative Accommodation

If you are knocking down and rebuilding your existing home, you will need somewhere else to stay during the process. Bear in mind that the average knockdown and rebuild timeframe is between 12 and 18 months but can be longer due to delays. Ensure you have appropriate funds and/or someone you can stay with for the knockdown rebuild project.

Frequently Asked Questions

Since knockdown rebuilds are becoming more common, here are a few frequently asked questions we receive.

Is a Knockdown Rebuild Worth It?

A knockdown rebuild might well be worth your effort, time and money if the dwelling on your property is in dire disrepair to the point of being unsalvageable. Or, if your insurance company has offered you a sum following a catastrophic fire or flood that would make a knockdown rebuild on your existing lot more cost-effective than buying an existing home elsewhere.

Knockdown rebuilds can be more expensive than buying a new lot and building a new home, due to the demolition costs. Still, if you can’t bring yourself to part with a historical or emotionally significant plot of land, then a knockdown rebuild might be worth the cost.

How Much Can I Borrow for a Knockdown Rebuild?

Loans for knockdown rebuilds fall under Renovation Loans from most banks or lending institutions. If you conduct your knockdown rebuild with a licensed builder (which you always should) you can borrow 90% of the land’s value, or 95% of the land’s total cost, plus construction costs.

How Long Does a Knockdown Rebuild Take?

The average timespan of a knockdown rebuild is between 12 and 18 months.

Final Thoughts

If you’ve been searching for that perfect property and you’ve found it, but there is an annoying existing structure on it, or perhaps you’ve been unfortunate enough to have a catastrophic fire or flood that’s compromised your home to the point of it being unsalvageable, considering a knockdown rebuild to maintain a connection to the land on which your dear home once stood, isn’t a bad idea.

If you need design ideas for your new home once the demolition is complete, contact us at Provincial Homes.