KJ Tait


We have a specialist team experienced in carrying out daylighting assessments. These assessments are undertaken in support of planning applications for new build projects or extensions which could impact on adjacent developments.

The Daylighting Team are also involved in projects to maximise the daylighting in buildings and we are experienced in conducting climate-based daylight modelling assessments.

We offer the following assessments:

Daylight & Sunlight Impact Assessments for Planning

For most new urban developments, it is necessary that a daylight and sunlight impact assessment will be required for submission to the local planning authority.

These assessments are required to ensure that the quality of daylight and sunlight at adjacent properties and gardens is not significantly impacted upon by the new development and can include the following:

- Review proposed and existing view of sky line
- Assessing the quality of internal daylight within a proposed building
- Predicting the daylight/sunlight impact of a development at the windows of adjacent buildings
- Predicting the daylight/sunlight impact of a development on adjacent public areas, gardens or development land
- Right of Light assessments at existing dwellings (England only).

This is typically assessed through using modelling software to accurately build a 3D model of the proposed development and adjacent areas to allow us to predict the Vertical Sky Component (VSC) values at the existing dwellings before and after the proposed development.

Spatial Daylight Autonomy (sDA) and Annual Sun Exposure (ASE)

Calculation For the WELL Building Standard requirements:

The WELL Building Standard is a leading tool for advancing health and wellbeing in buildings globally. WELL’s flexible framework aims to improve health and human experience through design.

The Standard stipulates criteria to find a balance between sDA, which measures the percentage of floor area that receives adequate sunlight, and ASE, which measures the percentage of floor area that receives too much direct sunlight.

To achieve the desired credit, analysis is carried out using 3D modelling software to simulate the amount of sDA and ASE within an area.

Average Daylight Factor (ADF) Calculation

Average Daylight Factor (ADF) calculations demonstrate how the level of light inside a building compares to the level of light outside and estimates how much light will actually reach occupants of a building.  ADF calculations are a common requirement for the BREEAM assessment.

BREEAM Health and Wellbeing criteria stipulate the minimum daylight requirements within occupied areas of a building. To achieve the desired credit, daylight analysis is carried out using software to simulate the amount of available daylight within an occupied space.

Climate Based Daylight Modelling (CBDM)

KJ Tait work with leading Architects and construction companies as part of the UK Government's Education & Skills Funding Agency (ESFA) Priority School Building Programme (PSBP).

All new ESFA funded school developments are required to meet the ESFA specification for the provision of adequate daylight to teaching spaces and other occupied rooms.

Climate Based Daylight Modelling (CBDM) is a highly complex and accurate method of daylight analysis which analyses the available daylight through a school day. This is a crucial tool to influence the internal space planning and external façade design of school buildings to ensure adequate daylight is available within a classroom during the school day throughout the year. CBDM uses two criteria to assess this.

The first criterion sets a Useful Daylight Index (UDI). This is detailed as the annual occurrence of illuminance across the work plane that is considered “useful”.

The second criterion calculates the Spatial Daylight Autonomy (sDA). This is the amount of time a space can expect to reach a target illuminance level on the working plane.

As recommended in the EFA guidance for schools, the calculation will be carried out over the course of an entire year including weekends and the holiday period between the hours of 8:30am and 4.00pm.

Internal and external obstructions immediately associated with the rooms will be included within the simulation.


KJ Tait, were appointed by CDA Architects, on behalf of S1 Developments, to carry out an assessment of the daylight available at and around their proposed new residential development located at the Ocean Drive gap site in Leith.
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KJ Tait were appointed by Dandara to carry out an assessment of the daylight available at and around their proposed new residential development located at the Pinkhill site in Edinburgh.
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