The True Cost of Permeable Concrete: Looking Beyond Cost per Square Metre
One of the most common questions surrounding permeable concrete is simple: does it cost more than conventional concrete?
When the concrete surface is considered in isolation, the answer can be yes. Nationwide comparisons indicate permeable concrete itself can cost approximately 50% more than a conventional concrete pavement.
However, comparing the cost of the concrete alone doesn’t provide a complete picture.
Permeable concrete forms part of the site’s stormwater management system, meaning it can potentially reduce or eliminate other infrastructure that would otherwise be required.
Looking at the complete stormwater system
A conventional impermeable pavement needs to collect surface water and direct it somewhere.
Depending on the project, this can require infrastructure such as strip drains, sumps, pipework, filtration devices and stormwater storage.
Permacore® instead allows stormwater to pass directly through the pavement surface and into the underlying pavement structure.
For paved areas greater than approximately 80 m², the ability to remove components such as strip drains and sumps can mean the overall solution becomes cost neutral when compared with a conventional pavement and its associated drainage infrastructure.
Opportunities on larger developments
The potential benefits become even more significant when permeable pavement is considered across a larger development.
Depending on the stormwater design, Permacore® can contribute to reducing or eliminating the need for separate stormwater filtration or storage infrastructure.
Rather than treating the pavement and stormwater system as separate elements, permeable concrete allows the hardstand itself to perform a stormwater management function.
Making better use of constrained sites
Another consideration is impermeable site coverage.
Because Permacore® allows water to infiltrate through the pavement, the area may be able to be removed from impermeable hardstand calculations, subject to the requirements applying to the project.
This can be particularly valuable on constrained residential developments where impermeable area limits affect how much of the site can be developed.
A permeable pavement solution can therefore potentially create greater flexibility for driveways, parking areas and other hardstand while allowing more of the available site area to be utilised.
Stormwater storage within the pavement system
Permacore® systems can also be designed to attenuate a specified volume of stormwater.
For example, where a project needs to manage 5,000 litres of stormwater, the pavement and underlying basecourse can be modelled to determine whether that volume can be accommodated within the system.
This can provide an alternative to allocating valuable site area to a bulky standalone storage solution.
Compare systems, not simply surfaces
The value of permeable concrete is best assessed at a whole-of-project level.
While the initial concrete cost may be higher, potential reductions in drainage infrastructure, stormwater treatment, storage requirements and impermeable site coverage can significantly change the overall project equation.
For architects, engineers and developers, considering permeable pavement early in the design process provides the greatest opportunity to identify these efficiencies.
DesignHub can provide Permacore® design assistance to help determine how a permeable pavement system could integrate with your project.
Considering Permacore® for an upcoming project? Submit your project through DesignHub to access design assistance, specification support and guidance on incorporating permeable concrete into your project.
