When designing a building, keep in mind the following considerations…
1. Design to a budget
Let the budget inform the design, not the design informing the budget.
2. Lines on paper are cheaper than walls on site
Understand the decisions that have been made in creating the plans.
3. Every decision has a cost associated
The earlier this decision is made, the less it will cost. Projects are never completed without alterations to the starting documentation, and more changes mean more expense.
4. Get ahead of the project
The earlier significant trades and suppliers are consulted, the better. These trades and suppliers can provide vital early feedback. It hurts to hear the words “if only you’d called me when you were designing this thing”.
5. Bricks are heavy
And the higher a brick wall is, the more expensive it becomes. This is because of the cost of scaffolding and getting the bricks and materials up to the working height.
Upper level brickwork, if the building is anything other than a double height rectangle, also generally requires significant structural steel to carry the brickwork.
6. Proximity of services
It’s a small issue, but ensuring services are close to the source (like kitchen and bathroom being close to the hot water service) diminishes the amount of materials required.
7. Design for timber
Not because timber is better than steel, but because if minor changes mean no structural steel is required, there is one less supplier and one less trade to worry about. There will always be carpenters involved in the building.
There are span tables available from manufacturers and within the Residential Timber Framing Code to help with this. This can also be an instruction for the project engineer. In many cases, engineered timber can be used in place of steel if your engineer knows this.
8. Design for climate
Take measures to site the building properly and orient the windows and shade elements. This controls the cost of the balancing measures that otherwise need to be taken; like air-conditioning, double glazing, heating and insulation.
9. Consider the ‘ready dimensions’ of the materials you will be using
This eliminates much waste, and encourages economy.
For example timber comes in 300mm increments; most board products are 1200mm wide and 2400mm long – this is the old 8’ x 4’.
A good example of the way this might affect a design is wall heights. Plasterboard is available in sheet widths of 1200mm and 1350mm, so when nominating wall heights, the designer should keep this in mind.
In designing a room, dimensions of 2400 x 3600x 2700 will be lot cheaper than an almost identical room of 2450 x 3500 x 2800.
This can turn a $200,000 structure into a $600,000 project. Everything that can be specified in the building will affect the cost of building.
A $250 toilet or a $1500 toilet? A $15,000 kitchen or a $95,000 kitchen.
Understand your expectations and how they affect the project budget. Specify early, so as not to rush decisions.