Is it cheaper to extend or build a granny flat?
A granny flat typically costs around $120,000 - $200,000 to build in Sydney, while a house extension usually ranges from $200,000 - $450,000+. However, the final cost depends on several key factors:
Granny Flat Advantages:
Generally more cost-effective due to smaller size
Faster construction time (usually 8-12 weeks)
Separate structure means less disruption to main house
Clear council approval pathways under NSW Complying Development
Potential rental income opportunity
House Extension Advantages:
Adds directly to main house value
Can better integrate with existing living space
May be better if you need internal connection to main house
Often more flexibility with design options
Cost-influencing factors:
Site conditions and access
Size and quality of finishes
Council requirements
Whether you need temporary accommodation during construction
If your primary goal is additional living space at lower cost, a granny flat is typically the more economical option. However, if you want to increase your main home's value and create integrated living space, an extension might be worth the higher investment.