Can you build a granny flat on a duplex?

In Sydney, building a granny flat on a duplex property is generally NOT permitted under standard complying development rules. Here's why:

Key Restrictions:

1. NSW Planning Rules

• Granny flats are only allowed on lots with a single primary dwelling

• Duplexes are considered two primary dwellings

• Each duplex unit is treated as a separate dwelling

Possible Alternatives:

1. Development Application (DA)

• You could apply through your council

• Success rates very low

• Would need strong justification

• Much more complex and expensive process

  2. Other Options to Consider:

• Converting existing space within your duplex

• Adding an extension instead

• Internal renovation to create separate living area

Factors to Check:

• Your local council's specific rules

• Property zoning

• Strata title restrictions (if applicable)

• Floor space ratio requirements

• Site coverage limits