Permcon solves site coverage limits

With granny flats set to be exempt from requiring a consent in early 2026, many homeowners are seeing an easier path to adding a second dwelling to their properties. However, with site coverage limits still applying, increasing the build footprint could cause an issue when it comes paths, driveways and carparks. That’s where Permcon permeable concrete can offer a practical and sustainable solution

The government has passed the Building and Construction (Small Standalone Dwellings) Amendment Bill, enabling simple detached dwellings of up to 70m² to be constructed without a building consent from early 2026. In parallel, a proposed National Environmental Standard

(NES) is intended to remove the need for resource consent for one minor residential unit per site in relevant zones.

Site coverage rules remain

Despite these changes, site coverage requirements still apply. These rules – outlined in District Plans – vary by council and zone but typically allow between 40% and 75% site coverage, with a common limit of around 70% for impermeable surfaces in urban areas. Historically, buildings have been permitted to account for between 30% and 50% of site coverage.

Under the proposed NES, allowable building coverage would increase to 50%. However, there

is no proposed change to the overall cap on impermeable surfaces. This means that if buildings take up most or all of the permitted impermeable area, driveways and other hard surfaces may need to be permeable to remain compliant.

Permcon NZ director Stuart Girvan says permeable concrete can help unlock development potential.

“Using Permcon permeable concrete, we can convert a significant percentage of a property’s hard surfaces into permeable areas, allowing homeowners the flexibility to add an MRU while still meeting their local council’s District Plan standards.”

Girvan adds that landscapers should make sure to stay up to speed with the incoming regulations, and any local ones, that might prove useful when discussing requirements with clients.

“Many councils also require minimum areas of a developed site to be green and, if there are

no other options, installing artificial grass over Permcon permeable concrete can satisfy this requirement,” said Girvan.

Why use Permcon?

Permcon permeable concrete produces a hardwearing, pervious surface that allows stormwater to pass through the top course and into the open grade basecourse beneath. This allows stormwater to replenish the natural ground aquifer or be discharged to the stormwater network via under drains in a measured and controlled manner, reducing the peak flows of a storm event.

As such, permeable concrete pavements help reduce street flooding, improve the health of receiving streams and rivers by filtering debris and pollutants from the stormwater, and cool water as it infiltrates the permeable base system.

In addition, all Permcon installers are certified by Permcon and the permeable driveway comes with a Producer Statement 3 – documentation which confirms the installation was conducted correctly and the driveway will last for the intended duration.

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Get in touch with Permcon at permcon.co.nz or +64 27 224 1361