A project is a team effort, you and your designer must form a coherent team, since, you are planning what is most likely going to be the most expensive item you have ever purchased, you must get it right. So put effort into what you want, the result will be well worth it!
A design brief is to explain to your designer what your needs and wants are for your project, this will entail you being quite specific about a number of things, e.g what size bed you want in yours and the other bedrooms, king, queen, king single, how many people you want to seat at your dining table, what type of seating you want in your lounge room, how much bench/storage space you require in the kitchen/laundry. What ceiling heights you want, floor/wall finishes. External finishes, what style of architecture you like and want e.g contemporary modern/Hampton. Provide photo samples of what you want.
Most importantly what your budget is, this will direct the designer in the way to think, there is no point the designer producing a wonderful design that will cost $800k if you only want to invest $500k, all you end up with is a pretty drawing, in the same sense there is no pint telling him you have $250k when you really have $350k, because you will not end up with anything close to what you really want. Remember, there are 2 types of budgets, the Project budget and the Construction budget.
Construction Budget: Basically, this is just the cost to build the project;
Project Budget: This includes the Construction budget and also all the incidentals such as Council/PCA fees, Government fees, Consultants fees(e.g. Surveyor, Engineer’s etc.), preparation of the design, DA & CC documentation. It is always best to consider the Project budget!
Time frames are not just the time to build the project, it involves the planning stage, the approval stage and the construction stage, this can take between 9-18 months (for a project up to the value of $1m) depending upon the size and complexity of the project, the Council area and of course neighbours.