Builder Job Guide

Find a Builder for Home Extension Build

An extension build covers site preparation, structural work and finishes, with site conditions and chosen finishes strongly affecting the project's scope.

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32,355 local providers4.6 avg ratingTypical duration: 140-160 hours

What we'll ask you

4 quick questions for your estimate

Answer these and we’ll generate a personalised range in seconds before you post your job.

Pricing guide

The cost of an extension is driven by structural requirements, site preparation or remediation, and the finish level you select. Engineer-led works, heavy demolition or bespoke premium finishes typically increase materials and specialist labour, while plans, permits and project readiness can also affect the final quote.

  • Finish level and bespoke items

    Premium or custom finishes usually increase material and specialist labour requirements and may extend lead times.

  • Demolition and remediation needs

    Significant demolition, hazardous removal or repair of poor foundations generally adds scope through specialist disposal and site remediation.

  • Site and foundation conditions

    Sloping sites, unusual ground or specialist foundation needs typically require additional preparation and can lengthen the build programme.

  • Plans, permits and project readiness

    Having plans and permits ready usually simplifies pricing, while incomplete documentation or council requirements often add time and provisional allowances.

Home Extension Build

Estimated range

Request quote

Answer the estimate questions to refine the scope.

What moves this estimate

  • Finish level and bespoke items: Premium or custom finishes usually increase material and specialist labour requirements and may extend lead times.
  • Demolition and remediation needs: Significant demolition, hazardous removal or repair of poor foundations generally adds scope through specialist disposal and site remediation.
  • Site and foundation conditions: Sloping sites, unusual ground or specialist foundation needs typically require additional preparation and can lengthen the build programme.
  • Plans, permits and project readiness: Having plans and permits ready usually simplifies pricing, while incomplete documentation or council requirements often add time and provisional allowances.

Local results

Active providers

32,355

Average rating

4.6

  • I recently had the pleasure of having Mark C assist me with a claim for damage after a hail storm in October. Mark and his team were very professional in the way they handled my c…

    Jan Blackshaw

  • Richard came out and did an amazing job for us. He looked at my mum’s house and assessed the issues. He was able to identify some moisture issues that exist under the house and th…

    Alison S

  • I've heard and read of many experiences in regards to how inconvenient, messy and miserable restumping jobs can be as it is a meticulous, labourous foundation work especially on o…

    susanna ling

How it works

  1. 1

    Describe your job

    We ask targeted questions to scope your exact job.

  2. 2

    Get matched

    We match you with local providers for this job type.

  3. 3

    Compare and book

    Review quotes and choose the provider that fits.

Frequently asked questions

Do I need a builder licence for extensions?
Licensing for this trade is mandatory; you should engage a licensed builder for extension work. It's reasonable to ask to see their current licence and evidence of relevant experience for similar projects.
How do engineering requirements change the job?
Engineer-led packages typically include provisional sums for items like steel, piling or underpinning and require specialist labour. The final scope and costs are usually confirmed once engineer reports and designs are completed.
What are provisional sums in a quote?
Provisional sums are allowances included for uncertain items such as engineered works, hazardous removal or bespoke fixtures. They act as placeholders until detailed reports or selections are made, at which point the scope is usually finalised.
Who coordinates subcontractors and supervision?
Builders typically coordinate subcontractors and manage site supervision; quoted builder hours often reflect that coordination rather than total subcontractor labour. You should confirm with the provider what site management and inspections are included in their quote.
How accurate is the instant estimate?
Our estimates are built from research across thousands of local jobs and real pricing data. Use them as a guide when speaking to builders — your actual quote will depend on your specific job.
How many quotes will I get?
We'll match you with up to 3 builders initially. If you'd like more options, you can request additional matches.
Do I pay anything to get quotes?
No — the service is 100% free for homeowners.
Why do you need photos?
Clear photos cut surprises and price blowouts, saving you money.

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