How is the solar building envelope assessed?
The solar building envelope checks whether a proposed building fits within a set height and location limit to protect sunlight to the site and neighbouring properties.
It is assessed by:
- Identifying the relevant adjoining residential boundary, especially a northern boundary.
- Applying the required solar fence height, which depends on the development type and block category:
- Single dwelling – large block: 2.4 m in the primary building zone and 1.8 m for other areas.
- Single dwelling – midsized or compact block: 3 m in the primary building zone and 2.3 m for other areas.
- Multi-unit housing: 3 m in the primary building zone and 2.3 m for other areas.
- Creating the solar envelope by projecting an imaginary solar plane from the solar fence:
- 31 degrees for single dwellings.
- 45 degrees for multi-unit housing.
The proposed building must fit within this envelope to meet solar access requirements.
Reference: Planning (Residential Zones) Technical Specifications 2026 (NI2026-303), Assessment Outcome 15 – Planning (Residential Zones) Technical Specifications 2026 | PDF
Short Answer
The solar building envelope is an imaginary 3D height and setback limit that controls how much a building can extend towards neighbouring properties. The assessment involves identifying the development type, applying the correct solar fence height and solar angle (31° for single dwellings or 45° for multi-unit housing), and checking that the proposed building fits within the envelope.
Detailed Explanation
The solar building envelope is assessed by checking whether the proposed building is contained wholly within the required solar building envelope. The purpose of the assessment is to ensure reasonable solar access to dwellings and private open space within the block and on adjoining residential blocks.
The solar building envelope is created by:
- Identifying the relevant adjoining residential block boundary, particularly where a northern boundary applies.
- Establishing the required solar fence height along that boundary. The solar fence height depends on the development type and block category, including whether the proposal is a single dwelling or multi-unit housing.
The required solar fence height depends on the development type and block category, including:
- Single dwellings on large blocks:
- 2.4 m in the primary building zone; and
- 1.8 m for other parts of the boundary.
- Single dwellings on midsized and compact blocks:
- 3 m in the primary building zone; and
- 2.3 m for other parts of the boundary.
- Multi-unit housing (excluding buildings exceeding 3 storeys in RZ5):
- 3 m in the primary building zone; and
- 2.3 m for other parts of the boundary.
- Projecting an imaginary solar plane from the solar fence over the development site:
- For single dwellings, the solar plane is projected at 31 degrees to the horizontal.
- For multi-unit housing, the solar plane is projected at 45 degrees to the horizontal.
The proposed building must remain within the applicable solar building envelope to comply with the solar access requirements.
No minimum block size does not remove the need for planning assessment.
Would you like to know what these rules mean for your property?
Get a Planning Assessment prepared by our experienced planning team.