To build or rebuild – weighing your options

Written by in Renovating

Love where you live but find that your home is bursting at the seams? If you’ve looked longingly at the stunning home of friends thinking ‘I want some of that!’  – you may be stuck in the eternal dilemma of whether to renovate or rebuild. With a decision of such magnitude, involving a serious outlay of money, it is no wonder that many people are in limbo, unable to commit to either option for fear of making a costly mistake.

Ultimately the choice of whether to retain and expand an existing house or start afresh on the same block will be dictated by a number of factors.

These factors include:

  • Financial considerations
  • Risk of over-capitalising
  • Condition and architectural relevance of the current building

To find out the best outcome for your situation, let’s take a pragmatic view of each scenario including estimated costs, benefits and drawbacks.

Cutting to the chase – cost comparison

Whilst there are many factors involved when comparing knock down rebuilds in Sydney with a second storey extension, most people cite cost as the primary decider.

A number of variables will influence the final cost of an extension, the main one being the extent and scope of works. According to a reputable trade site, plan to budget around $1,850 and $3,300 per square metre for an extension carried out by a builder.

Note that companies specialising in extensions may quote substantially higher than this figure. A fixed price quote will factor in a contingency to cover unforeseen circumstances. A builder, on the other hand, may simply be quoting for the work stipulated, meaning costs can spiral if issues such as structural damage are uncovered which require rectification prior to being signed off by a building inspector, enabling works to continue.

For those constrained to a tight budget under $150,000, where the home has no historical value or architectural significance, a simple fibro second storey extension may be the only viable option.

On the other hand, a quality job involving significant structural changes and/or the addition of a second storey may start upwards of $300,000; comparable to the cost of building a new home.


In the case of extensions, partial demolition is time-consuming and requires a great deal of planning and care. For second storey additions, the ground floor may require reinforcement to the foundations and a major redesign of the floorplan.

On the other hand, project home builders can pass significant savings on to buyers through their ability to buy in bulk. They will often have a wide range of floor plans to choose from, mitigating the need for architects and draughtsmen.

Of course, money is only one factor influencing the decision, so let’s look at other considerations.

Up and out renovations

A sympathetic renovation/extension to a home can be truly stunning; adding value and space whilst retaining the charm of the current residence. ‘Sympathetic’ means it should be in keeping with the style and era of the original building and contain complementary features and design facets to blend seamlessly in with the existing roof line.

It must be factored into your decision that these types of renovations involve substantial upheaval and best results may require you to temporarily relocate in order for a successful outcome.

Ask yourself these questions about your current property:

  • Does the floor plan lend itself to the extension i.e. room for staircase?
  • Are there any council limitations surrounding building up or alternatively demolishing existing homes due to their historical significance or other overlays?
  • What is the condition of areas of the home not considered within the scope of the renovation, i.e. window frames, significant subsidence and cracks, plumbing or wiring?

Knock-down rebuild


Drive through many previously modest suburbs and you will quickly appreciate how knock-down rebuilds have transformed these neighbourhoods into desirable, sought after pockets.

Some advantages of a knock down/rebuild include:

  • Customisable floor plans
  • Totally new product with a warranty
  • Predictable costing with no blowouts
  • Scope to rearrange the placement of the home on the block

Often people choose to extend rather than rebuild in order to retain period features which may be of historical value or in keeping with the character of the neighbourhood. In response to this, there are a number of home builders now offering period designs which blend in with the character of inner suburban streetscapes.



As we have seen, the decision of whether to extend or rebuild must be taken on the merits of each case. Begin by approaching your lender to discuss your prospects for borrowing to fund each scenario. Whichever path you choose, selecting a builder with verifiable credentials and a solid track record will be your best starting point. Best of luck!