The cost to develop a project varies depending on the complexity and whether its an extension or a new dwelling. The design phase goes through several stages. Initial meeting / briefing, gathering information and researching the regulations relating to your site, preparing initial sketches and reviewing them. Preparing more detailed sketches then progressing to enough documentation to lodge a Development application or Complying Development application. A Complying Development application involves all the planning to be done up front before submitting it while a Development Application can be submitted without having to have prepare final documentation. Both systems have their advantages and disadvantages.
Approx design and drafting costs for a basic residence or extension is $1200 for initial sketch. $3000 to $10000 for final architectural documents for construction. A detailed quote is given before starting any work.
Then there are the cost of consultant services that may be required for the project. Here is a list of potential consultants. The costs associated with these consultants will vary depending on the complexity of each job and is quoted separately:
Surveyors for surveying the land.
Structural Engineers design.
Hydraulic Engineers design.
Soil test report.
Interior Designer / colour consultant.