Preparing to build your home: costs and ordering

Tools, materials and labour are expensive; before making a start building your home, careful financial planning is essential. To avoid wasting money, you need to know how to estimate quantities of such things as concrete, timber and roofing materials. These tips will help you get started.

Early in the planning process, decide what you can afford to spend; your budget will govern many decisions, including the size of dwelling you construct. To estimate the size of what you can afford to build, divide your budget by the cost per square metre of floor area typically applicable to the construction method you intend to use.

There are costings for various building methods that are based on average homes built to a reasonable standard. They are available — usually for a fee — from building consultants (check the yellow pages directory or look online). Make a few hard-headed calculations if you plan to be self-sufficient: compared with buying direct from building materials suppliers, is it really worthwhile cutting your own timber, digging your own soil, bucketing up sand, making bricks or repairing and reusing second-hand materials?

You can also do the calculation in reverse.

• To estimate the cost of a particular design, multiply the floor area in square metres by the cost per metre for the type of construction.
• Because porches, verandahs and garages are not finished to the same level, add only half the cost for these elements.
• This total will be higher if there are access problems, difficult site conditions, engineering requirements or increased levels of finish over standard or non-standard fitout.

On the other hand, the cost may be reduced by using cheaper forms of construction, using your own labour or using second-hand materials. Allow a contingency of five to 10 percent to cover unforeseen problems. If the estimated cost is greater than the amount you had in mind, think about building the house in stages, to defray costs. A detailed costing for constructing your house can only be done once final plans are drawn and all materials have been specified. If you are an owner-builder, you may not need a fully itemized list. An indication of the likely costs may suffice.

These guidelines will help you plan your budget accordingly and decide what you can afford to spend on your dream home.