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How much does it cost to build a granny flat?

Posted 2 years ago | By Latitude Homes

NZ60 hector Granny flat

Granny flats are in high demand in New Zealand. We know it from experience. Every week we get this type of enquiries from all across the country:

  • ‘We are looking to build a home and income property as my grandparents have sold their house and will be moving with us’

  • ‘We would like to build a four bedroom house with a separate granny flat…’

  • ‘We are planning to build a granny flat in our backyard. What are the costs if we opt for the DIY kitset granny flat?’

  • ‘We are looking for a 2-3 bedroom granny flat in our section. Can you assist me with the plans?’

If you are planning to add a second dwelling unit to your property for some extra rental income or provide for a growing family, here’s all you need to know. 

Content summary

How much does it cost to build a granny flat?

This is the most common question when a customer asks about granny flats. We have kitset granny flats starting at $67,870, an ideal option if you are confident with your DIY skills. If you want us to do all the work, we have full build options from $164,500. 

The cost will vary depending on three factors:

  1. The house plan you choose: The cost above is for the Hector plan, our smallest.

  2. The region you are planning to build in: Pick your house plan, then select your region to see the pricing that will apply to you.

  3. The build option you choose: We have four build options: kitset, full build, shell internal, shell only. See what’s included in each option: BUILD OPTIONS.

  4. If you want to customise the plan or not.

All our plans comply with New Zealand regulations and when you choose the Full Build option are covered by a 25 year structural warranty

What are the Granny Flat Plan Options?

Granny flats are usually small house plans, with just enough space to ensure privacy and independence from the main house without compromising comfort. This type of house plan usually has one or two bedrooms, a bathroom and a kitchen. The space is fully optimised to fit in small sections. Local authorities set a maximum floor area for second dwellings without having to subdivide the land. In most regions it ranges between 60m2 and 70m2. At Latitude Homes we have two 60m2 house plans, and a 70m2 one.

Hector 60m2 granny flat plan 

NZ60 Hector plan

The Hector is a compact and functional 60m2 house plan. This very popular small home has 2 bedrooms, 1 bathroom, and is favoured for its simple layout.  The kitchen has lots of bench space, with the laundry cleverly hidden behind double folding doors. The two large bedrooms each have built-in wardrobes. The bathroom has a shower and separate toilet. 

Wairoa 60m2 granny flat plan

NZB60 plan

The Wairoa is a small but perfectly formed house plan. This solid block house has two bedrooms with built-in wardrobes. The functional single bathroom has a large shower.

Motu 70m2 granny flat plan

NZB70 Motu plan

The Motu house plan is bigger and has one more bedroom than the Wairoa and Hector plans. However, it’s small enough to work as a granny flat on bigger sections. It has 3 large bedrooms with built-in wardrobes, and one bathroom. Like the Hector, the separate laundry is cleverly hidden behind double doors in the open plan kitchen, living and dining area.

What other costs do I need to consider?

There are other costs not directly associated with the actual granny flat build that you should keep in mind. For example, excavation costs, council costs, drainage, driveways, landscaping, fencing, power and water supply. We suggest that you allow an extra 5 - 10% on your budget for extra unforeseen costs.

Can I customise the plans?

Yes, you can. However, our plans have been priced to ensure the most cost-effective way of building. Talk to your local Latitude Homes team to discuss your requirements and get a cost estimate.

What are the rules in my location?

In New Zealand, the rules are stated in the Building Act 2004, plus various regulations of the building code. Then each local authority runs the building consent process using district plans to decide what is allowed in each zone. 

Do you want to know if you can build any of our granny flats on your property? Our local team will give you all the info you need and help you get started. Contact us. 


Thank you for all your hard work in getting our build across the line, we are extremely grateful for what both you and Jess have done.
Craig and Kelly