14.3 Roof-mounted solar panel arrays of less than 40 square metres in size
A building consent is not required for the installation of a roof-mounted solar panel array that measure less than 40 square metres.
Multiple arrays can be installed as long as each array does not exceed the size limit and is mounted on an independent roof structure.
What the law says
Schedule 1 of the Building Act 2004
Exemption 28D. Roof-mounted solar panel arrays of less than 40 square metres.
Building work in connection with a ground-mounted solar panel array outside a rural zone if:
(a) the array does not, or, if there is more than 1 array mounted on the roof, the arrays in total area do not, exceed 40 square metres; and
(b) the array is, or, if there is more than 1 array mounted on the roof, the arrays are each, supported by a frame or structure; and
(c) the frame or structure is attached to the roof with structural fixings; and (d) either:
(i) the design wind speeds do not exceed 44 metres per second (calculated using Verification Method B1/VM1); or
(ii) the array is located in a wind zone no greater than high (as defined in Acceptable Solution B1/AS1)
How it works
The size of solar panels must be measured according to the actual area of the array(s) installed.
Before you begin, please read the Notes for solar panel arrays: 14.1. to 14.4. section.
Under this exemption you are able to install multiple solar panel arrays as long as the total area of the arrays mounted on each independent roof structure is no more than 40 square metres. If the total combined array area will measure more than 40 square metres, or if the wind speed is greater than “high”, refer to section 14.4 Roof-mounted solar panel arrays of more than 40 square metres or where the design wind speeds exceed 44 metres per second (exemption 48A).
For non-rectangular buildings, an independent structure can be described as independent parts of the roof that are supported by separate structures (load bearing walls etc).
Your solar panel arrays should be installed at least 600 mm away from roof edges and gutters, and must not extend beyond the roofline.
Building A has a single roof structure, and so under this exemption could only support up to 40 square metres without a Chartered Professional Engineer’s design or a building consent.
Building B has two independent roof structures, and so under this exemption the building could support multiple solar arrays without a Chartered Professional Engineer’s design or a building consent as long as the total area of the arrays mounted on each independent roof structure is no more than 40 square metres.
What is exempt
- A homeowner decides to install a 35 square metre solar array panel to the roof of their house. Council maps indicate that the property is in a high wind zone (i.e. wind speeds less than 44 metres per second). A building consent is not required due to the size of the array and the wind zone.
- A school intends to add multiple roof-mounted solar panel arrays to classrooms that face north. Each array will measure less than 40 square metres and the wind zone is high. A building consent is not required if each array will be mounted on an independent structure.
What needs consent
- The owner intends to install a single solar panel array on the roof of their house, measuring 30 square metres. The wind zone is greater than high, which means that the structural fixings attaching the array to the roof will need to be designed or approved by a chartered professional engineer. However, the owner does not want to use pre-engineered fixings that have been signed off by a Chartered Professional Engineer, nor do they intend to engage an Engineer to design the fixings. A building consent is required.
- For any roof-mounted solar panel installation that does not meet the conditions for this exemption, refer to Section 14.4 Roof-mounted solar panel arrays of more than 40 square metres or where the design wind speeds exceed 44 metres per second (exemption 48A).