Minor Dwellings & Granny Flats in Warkworth and Rodney

A minor dwelling gives you room for family, guests or a rental income without moving house. McMahon Builders designs and builds minor dwellings, granny flats and sleepouts across Warkworth, Matakana, Kaipara and the wider Rodney area. We've built more than 300 projects over 20 years, and our licensed building practitioners handle the build from the first site visit to handover.

 

What we build

• Standalone granny flats and minor dwellings, usually one or two bedrooms

• Barn-style units and studios, like our Edgerly Barn project

• Sleepouts and self-contained guest units

• Minor dwellings on rural lifestyle blocks, where water, wastewater and access are part of the job

 

Building consent or the 70 m² exemption

Since January 2026, a simple standalone home of up to 70 m² can be built without a building consent, as long as every condition of the exemption is met. It still has to meet the Building Code, and licensed builders must do or supervise the work. You also need a Project Information Memorandum (PIM) from council before work starts.

 

The exemption suits a compact unit on a straightforward site. A full building consent is usually the better route when you want more than 70 m², a second storey or an attached unit, or when the site is sloping or needs engineered foundations. We'll tell you which route fits your site at the first meeting.

 

Rural sites around Warkworth and Matakana

On lifestyle blocks, the building is often the easy part. We price the site work alongside the build, so there are no surprises:

• Wastewater: whether the existing septic system can take a second dwelling, or a new system is needed

• Water: a separate tank or a link to the main house supply

• Power and data: trenching from the existing supply

• Access: trucks, diggers and concrete pumps need a firm route in winter

 

How a minor dwelling project runs

1. Site visit and brief: we look at the section, services and access, and talk through how you'll use the unit.

2. Design and route: we work with your designer, or recommend one, and confirm consent or exemption.

3. Written proposal: you get the scope, timeframe and cost in writing before you commit.

4. Council paperwork: PIM, consent or exemption notices, lodged and tracked.

5. Build: our licensed team builds it, with regular updates.

6. Handover: final checks, records of work and council sign-off.

 

Minor dwelling FAQs

 

Do I need a building consent for a granny flat?

Not always. A standalone, single-storey unit of 70 m² or less can be built under the January 2026 exemption if it meets every condition. Larger, attached or complex units still need a building consent.

 

How long does a minor dwelling take to build?

The build itself is usually the quickest part. Site services, wastewater design and council paperwork set the overall timeline, so it helps to start those early.

 

Can I rent out a minor dwelling?

Often yes, but check your district plan and insurance first. A long-term rental also needs to meet the Healthy Homes standards, so we plan heating, ventilation and insulation for that from the start.

 

Do you build minor dwellings on rural lifestyle blocks?

Yes. Most of our minor dwellings are on rural sections around Warkworth, Matakana and Kaipara, and we price wastewater, water, power and access as part of the job.

 

Can you work with my own designer or architect?

Yes. We regularly price plans from designers and architects, and can suggest changes that keep the design but cost less to build.

 

Thinking about a minor dwelling? Send us your plans or ideas, or call 021 425 129 for a site visit.