Permeable Concrete Melbourne

Permeable concrete in Melbourne, poured on site

Permeable concrete is a no-fines mix. Cement, water and coarse aggregate, with the sand left out. That leaves a matrix of interconnected voids running through the slab, typically 20 to 26 per cent of the volume. Conventional concrete sits at 3 to 5 per cent. Rain lands on the surface, passes through those voids and reaches an open-graded stone base underneath.

It arrives on a truck and goes down as a continuous pour. No units to lay. No joints filled with grit across the area. If you have been pricing permeable pavers, that is a different product from a different trade, and we set out the comparison in permeable concrete vs pavers.

Infiltration through the surface commonly runs between 80 and 720 litres per minute per square metre. The low end of that range already takes more water than any Melbourne storm will land on it.

The strength question

It is the first thing people ask. Driveways, footpaths and car parks are typically specified in the 20 to 25 MPa band, and the wider class runs about 5 to 25 MPa. That carries cars, utes and light commercial vehicles at driveway speeds. What we will not put it under is high-speed heavy traffic, and we say so before anyone prices a pour. Strength is a design input. It gets set in the mix and the base, not discovered afterwards.

Melbourne soil decides what goes under the slab

Melbourne soils change block to block. Reactive clay runs through the eastern suburbs. Heavy basalt soils sit west of the city. Both drain slowly.

So on tight clay we do not pretend the water soaks away. The open-graded base is designed as a storage layer with a controlled outflow. The pavement still lifts the water off the surface, still cuts the peak flow leaving the property, and still keeps puddles off the driveway. It meters the water out instead of pushing it into ground that will not take it.

Where the ground does drain, we let it. On sandier pockets and better profiles, more of the water goes straight into the subsoil and the base gets shallower. That call belongs to the site, not to a rule of thumb, which is why we want to stand on the block and look at levels, fall and soil before anyone talks square metres.

Clause 53.18, BlueFactor and council permeability limits

Victorian planning schemes ask new development to meet best practice stormwater standards under Clause 53.18. Councils want that shown with a score.

The STORM tool was retired in October 2025. BlueFactor now does that job for small residential sites up to about a hectare, and MUSIC is still used for larger or more complex proposals. Permeable paving counts as a treatment measure in those assessments, which is why it turns up on so many townhouse and single-dwelling applications across Melbourne. There is more detail in our BlueFactor explainer.

Site coverage is the other lever. Plenty of Melbourne councils cap impervious area or set a minimum permeable area per lot. A permeable surface can bring a site back inside the cap without shrinking the build or burying a detention tank in the front yard.

We are not your planner, and we will not promise you a council outcome. We work alongside your building designer, hydraulic consultant or civil engineer and tell them exactly what the pavement and base will do.

Maintenance, and the clogging question

Clogging is the real failure mode. Not cracking, not collapse. Sediment, leaf litter and airborne dust slowly fill the surface voids, and a neglected surface in a dirty setting can lose most of its infiltration within a few years.

The fix is a sweep. Vacuum sweeping, quarterly to annually depending on how much dirt the site sees. If it has been left too long, a pressure wash followed by vacuuming recovers most of the lost capacity. Never a rotary broom. A broom pushes debris down into the voids and makes the problem worse.

Design does the rest. Keep garden beds and unstabilised soil from draining onto the pavement, restrain the edges, and stabilise bare ground upstream while the build is still running. Do that and 30+ years is a fair expectation.

It does not have to look industrial

Exposed aggregate, oxide colours and our Ultracon resin finishes all read as finished surfaces rather than back-of-house paving. Colour and aggregate choice get locked in before the pour, so it is worth raising early.