Questions & Answers

What is the solar building envelope on my block, and did it change?

The solar building envelope controls require buildings to fit within a projected plane from the solar fence on the northern boundary of an adjoining residential block to protect neighbouring solar access.

  • Single dwellings on large blocks: Solar fence heights remain 2.4 m in the Primary Building Zone (PBZ) and 1.8 m elsewhere.
  • Single dwellings on mid-sized and compact blocks: Solar fence heights are 3.0 m in the PBZ and 2.3 m elsewhere.
  • Multi-unit housing (excluding buildings over three storeys in RZ5): Solar fence heights are 3.0 m in the PBZ and 2.3 m elsewhere.
  • The projection angle remains 31° for single dwellings, while multi-unit housing now uses a 45° projection angle instead of 31°, allowing greater design flexibility while maintaining solar access protections.

Reference: Planning (Residential Zones) Technical Specifications 2026 (NI2026-303), Assessment Outcome 15.1 – Planning (Residential Zones) Technical Specifications 2026 | PDF

Last reviewed: 2 August 2026 Information current as at: 1 September 2026

Short Answer

For a single dwelling on a large block, the solar fence heights are unchanged: 2.4 m within the primary building zone and 1.8 m along all other parts of the boundary, on any northern boundary of an adjoining residential block. The projection angle for single-dwelling housing remains 31 degrees. Multi-unit housing now projects at 45 degrees instead of 31 degrees.

Detailed Explanation

Under the Planning (Residential Zones) Technical Specifications 2026 (NI2026-303), 15.1 explains the Solar Building Envelope requirement, which ensures that new buildings are designed to minimise overshadowing of neighbouring residential properties. Buildings must be contained entirely within an imaginary envelope created by projecting a plane upward from the solar fence located on any northern boundary of an adjoining residential block. The projection angle depends on the housing type.

For single dwellings on large blocks, the solar fence heights remain:

  • 2.4 m within the Primary Building Zone (PBZ).
  • 1.8 m along all other parts of the boundary.

For single dwellings on mid-sized and compact blocks, the solar fence heights are:

  • 3.0 m within the Primary Building Zone (PBZ).
  • 2.3 m along all other parts of the boundary.

For multi-unit housing (excluding buildings exceeding three storeys in RZ5), the solar fence heights are also:

  • 3.0 m within the Primary Building Zone (PBZ).
  • 2.3 m along all other parts of the boundary.

The projection angle (X):

  • 31° for single-dwelling housing, maintaining the existing solar access controls.
  • 45° for multi-unit housing, replacing the previous 31° projection angle. The steeper angle allows greater building height and design flexibility while still protecting reasonable solar access to adjoining properties.

Overall, the amendment does not change the solar fence heights but changes the projection angle for multi-unit housing from 31° to 45°, while retaining the 31° projection angle for single-dwelling housing. This provides increased development flexibility for multi-unit projects without altering the established solar envelope controls for single dwellings.

Key Point

No minimum block size does not remove the need for planning assessment.

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