There are two main ways under the Building Act that non-licensed people may build:
1. Non-Consent able Buildings
Residential building work that doesn't require a Building Consent may be built by non-licenced people.
However, the work must still be built to comply with the Building Code.
See Building Code
2. Owner-Builder Exemption
a) You live in or intend living in the house including crib or holiday home
b) You carry out the restricted work yourself or with unpaid help from family or friends
c) You haven't carried out any other restricted building work within the previous three years.
All such work still requires Building Consents and Local Authority building inspections.
All plumbing and drainage needs to be carried out by a Licenced Practitioner.
You will also need to fill out an “Owner-Exemption Form” for Building Consent and submit it to your local council.
This varies product to product and dependent upon specific materials used. Pre-cut material packs will generally carry a two year workmanship warranty with warranties on materials from the individual material suppliers. Specific warranties are given for each product when supplied.
All Barn Kits include an engineered design including Producer Statement PS1 and prepared in accordance with AS/NZS 1170, NZS3603, NZS 3604 and approved documents of the NZ Building Code as noted on the drawings.
Typically for a non-habitable structure you don’t, however your local council will likely have areas that they have identified as needing further investigation, so it is best to contact your local council and ask if your site is ok before applying for Building Consent.