Our expert assessors can provide a Daylight and Sunlight Assessment to help you with site layout planning and Local Authority planning applications.

What is a Daylight and Sunlight Assessment?

A Daylight and Sunlight Assessment (DSA) is a tool used in the built environment to assess the impact of a proposed development on existing daylight and sunlight levels.

As a developer, you need to consider the external environment around your project. To ensure your project does not significantly impact its surroundings, it’s often necessary to undertake a DSA.

Once your assessment is complete, you can use it to help you maximise the use of natural light in your building while minimising potential impacts on existing levels of daylight and sunlight to neighbouring properties, gardens, and amenity spaces.

sun shining through trees and a building

Our services include:

  • Daylight Assessment simulations for complex commercial buildings to determine daylight factors and daylight distribution analysis.
  • Overshadowing Assessments for new developments to support planning applications.
  • Average Daylight Factor for new and existing buildings to highlight where adequate levels of sunlight should be attainable.
  • Sunlight Assessment calculations to estimate the annual amount of sunlight for a given window.
  • Maximum Envelope Calculations during early planning to support developers in space utilisation vs daylight and sunlight restriction.

BRE Daylight and Sunlight Guidelines

BRE Daylight and Sunlight Guidelines provide technical guidance on assessing daylight and sunlight levels in buildings. They help your design teams ensure that occupants of new buildings are supplied with a reasonable level of natural light while protecting neighbouring properties from overshadowing or glare.

The information contained within the BRE guidelines is essential to understanding the requirements when undertaking a Daylight or Sunlight Assessment. When implemented correctly, they help create high-quality spaces without compromising the environment.

Developed by industry experts, the guidelines detail an array of techniques for analysing the impact of a development scheme on its surroundings, including:

  • Assessing existing conditions
  • 3D modelling tools
  • Parametric studies
  • Physical measurements

When do you need a Daylight and Sunlight Assessment?

As part of any application submitted to local authorities or planning departments, developers must complete a Daylight and Sunlight Assessment and include it in the documentation.

Developers must ensure that the assessment is completed to a high standard and made available to local authorities and other interested parties prior to submitting their application. Failure to do so can result in delays or even refusal due to inadequate information being supplied.

Examples of when a DSA would be needed include:

  • When proposing large buildings like high-rise residential blocks, office towers, retail complexes or industrial units.
  • Any proposals which could affect the amenity of an area, such as overshadowing existing buildings or blocking views.
  • Any development situated in a conservation area which could have an impact on the setting.
sunlight shining between glass tall buldings

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