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Granny Flat Construction Costs

Granny Flat Costs

Typical build costs:

  • 1 bedroom (40-45m²): $80,000-130,000
  • 2 bedroom (55-65m²): $100,000-160,000
  • 2 bed + study (70-80m²): $130,000-200,000

What's Included

Standard granny flat includes:

  • Council approvals
  • Site preparation
  • Slab foundation
  • Full construction
  • Kitchen and bathroom
  • Electrical and plumbing connections
  • Basic landscaping

Additional Costs

  • Site slope: +$5,000-20,000
  • Sewer extension: +$5,000-15,000
  • Power upgrade: +$2,000-5,000
  • Premium finishes: +$20,000-50,000
  • Landscaping: +$5,000-20,000

Council Requirements

  • Maximum 60m² in most areas (NSW up to 60m²)
  • Must meet setback requirements
  • Private open space required
  • Parking may be required
  • Cannot be separately sold (attached to main dwelling)

Kit vs Custom

Kit/Prefab

Pros: Faster, fixed price, fewer surprises

Cons: Limited customisation, may not suit site

Custom Build

Pros: Designed for your site, any layout

Cons: Takes longer, potential cost overruns

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