Chris shares his top three ways developers can save money on multi-level projects.
1. Early Consideration Of Basement Construction
Basements can be the one of the main sources of unnecessary spending for developers, particularly for multi-residential and retail developments. Small issues or changes lead to either increased excavation costs or design costs going through the roof.
We often see basements being over-utilised or under-utilised. They’re either designed right to the boundary without allowing enough space for the structure to be built, or the space isn’t maximised, forcing developers to add a second basement.
Early engagement of a structural engineer, particularly before Development Approval submission can save time and money, particularly on multi-residential and retail developments.
If you can reduce the number of required basement levels on a development, on average you can save $500k per level.
The key is to effectively plan space early in the design process, and ensure basements aren’t being overpriced. This could include finding clever ways to keep basements out of the ground.
2. Post-Tensioned Concrete
Post-tensioned concrete is old technology, but has recently become very valuable and far more economical.
While not many companies use it, I recommend it because it’s the best method to increase the span of suspended slabs, and reducing the required columns. It can provide a 20 to 30 per cent span increase, or a 20 to 30 per cent reduction in slab thickness.
On residential developments, this means that you can increase floor to ceiling heights and sell units as ‘premium’ rather than ‘standard’.
Similarly, you can reduce your building height and save money that way. On retail or commercial projects, this allows increased open plan spaces, with fewer columns.
Builders have advised me that the cost of post-tensioned concrete construction is almost identical to reinforced concrete, and therefore doesn’t add excessive cost to the build. In fact, with post-tensioned concrete, you can cut down on reinforcement costs by up to half.
It used to only be economical on larger developments, but it’s now useful for smaller projects as well. On a large job, if you’re saving 30 per cent per level, over nine levels for example, you’re saving the equivalent of three slabs over that whole building.
The advantage of using post-tensioned concrete on smaller jobs is that it creates a better aesthetic and raises the overall value of the space.
3. Prefabricated Formworks
Recently, we’ve used prefabricated formworks on a number of projects. It’s a very simple and accurate construction process, and means that you don’t need to remove any formwork or blockwork – instead, it’s permanently concreted in.
The speed of construction is extremely fast – it can usually be turned around within a day or two for a typical floor plan.
The design is also very similar to normal concrete design, without worrying about the formwork costs.
Using prefabricated formworks can act as your fire separation wall, which is another positive. When developers are choosing between blockwork, columns, or in-situ walls (which are very expensive), they have to consider the fire and acoustic separation, which needs approval from a certifier.
With prefabricated formworks, you can essentially treat it the same as an in-situ wall system, however, your acoustic treatment can be directly applied to the wall system.