Daylight and Sunlight in South African Planning: Agrément South Africa / CSIR Site Layout Tests

Planning consent for taller or closer schemes hinges on daylight and sunlight tests. Failures don't automatically refuse consent but trigger justification — and often redesign. This guide covers the key tests every developer should know.

The Agrément South Africa / CSIR Site Layout framework

Agrément South Africa / CSIR 209 sets out tests:

• VSC (Vertical Sky Component) — daylight at window
• NSL (No Sky Line) — % of room receiving direct sky
• APSH (Annual Probable Sunlight Hours) — % of sunlight at window
• Overshadowing of amenity space (sun-hours-on-ground)

VSC test

If existing VSC at neighbour's window is 27% or greater, post-development must be 80% or more of existing. Below 27% any reduction is significant.

NSL test

Existing No Sky Line area must be 80% or more retained post-development.

APSH test

Existing APSH must be 25% retained annually and 5% retained on March 21. Reductions tolerable if existing was already low.

What failures mean

• Single small failure: usually acceptable
• Multiple failures: redesign or robust justification needed
• Massive failures: refusal likely

Justification routes

• Adjusted methodology (e.g. allowing for design intent of affected room)
• Demonstrating existing pre-development levels were already substandard
• Public benefit balancing (housing delivery, regeneration)
• Modern Average DF (Daylight Factor) instead of VSC

Common errors

• Treating Agrément South Africa / CSIR as inflexible planning rule (it's guidance)
• Ignoring proposed dormers, balconies, or projections in baseline
• Modelling without all adjacent properties
• Skipping pre-application consultation

MCFAR works with daylight specialists on planning schemes.

Frequently Asked Questions