The idea of building conventionally (where a builder turns up with his tools in his truck and then waits for his chippies, labourers and material deliveries before building everything from scratch) is really old hat.
Even though in 2020 the majority of construction is still done this way, that doesn’t mean it’s right. The “system” (for want of a better word) can be traced back to the early 1800s. Since then, we have built automated assembly lines for cars, phones and furniture, but when it comes to building and construction, we have somehow thought it best to stick to piece-by-piece construction.
I don’t really know why. My guess is that the level of intellect of those in the profession doesn’t see the ‘need for speed’ as a requirement. I base that guess on personal experience. I rarely see all building components brought to a site at the same time. Instead, trips to Bunnings, trips for coffee and toilet breaks intersperse the onsite working day. Phil (my friend and master builder) agrees. Judging by his age, I’d say he’s been a licensed builder for over forty years.
People (and even ants) tend to think of the shortest and easiest way from point A to point B. Carpenters and builders should be no exception. However, I believe the fundamental problem lies with paying for their services by the hour. When you agree to an hourly rate, you have essentially conceded your money to someone who through self-interest is bound to take as long as he can. Otherwise, why wouldn’t you use building systems that can halve onsite time? Why not avail yourself of efficiencies that at the very least can be achieved with better planning and process management?
There are also prefabrication building efficiencies that you can access today. Numerous prefab systems are available, including:
- timber walls
- galvanised steel walls,
- enclosed cassette systems
- structurally insulated panels
- polystyrene, mould-form construction
- lightweight concrete panels
The two least-costly (though not the fastest) systems that can be used are timber or galvanised steel walls. With all prefab extension systems, the trick is to keep the walls as rectangles that link with the main house. This avoids the need to alter the eaves and roof line.
It’s also important to carefully plan the design of prefab elements to avoid any unnecessary waste. For instance, if the wall system uses 450mm stud separations, then the structure should be designed in 450mm multiples. How the windows and doors fit also needs to be carefully considered. Choosing a door/window system that ‘slots in’ (as opposed to being fixed) is crucial. Use the same principle as if you were picturing how a hinged window fits into a window frame.
Finally, using a construction work flow chart can help you to bring in all your tradesmen at the right time. In the end, building efficiency comes down to timing and not changing anything after you start. A standard home extension should not take more than 60-90 days to complete.