Daylight Assessments Dorking London

Daylight Assessments Dorking London

Daylight Assessments Dorking London Here at Blackacre, we are a multi-disciplinary firm of Chartered Building Surveyors, providing a wide range of professional services. Daylight Assessments Dorking London.

When developing a property either for personal or individual needs, several documents and surveys are required. Part of the requirements for planning a new building is a report on the Daylight Assessments Dorking London. If you are building in areas where there are already neighbours, the local authority may require this to ensure your project does not inconvenience them.

What is Daylight and Sunlight Assessment

The daylight and sunlight assessment is a measure of the effect of a new building on the amount of sunlight received by neighbouring buildings. It could also be used to ensure every room within your building also receives sufficient sunlight. 

This assessment is different from the legal right to light, in that the latter assesses the effects the project or building has on neighbouring property. The methods used in daylight and sunlight assessment are also different. Determining the Daylight Assessments Dorking London is often done in compliance with BRE 209 standards. 

Several assessment calculations are carried out in determining the sunlight and Daylight Assessments Dorking London. These include;

Vertical Sky Component

The vertical sky component is a measure of the amount of sky that can be seen from the centre of the window. Sunlight is received from the sky hence for a good amount of natural light to be seen in the room, the vertical sky component should be high.

How is VSC calculated

The 25degree rule is employed in determining the VSC. From the centre of the window of the affected building, a 250 line from the vertical is drawn to the top of the proposed building. If this line is obstructed, more assessment is carried out.

If the VSC is 27% or more, it is said to be higher and allows a good amount of natural light into the room. Values less than 27% can still be excused if it can be determined that the VSC is not less than 80% of the former value before the new structure.

No SkyLine/ Daylight Distribution

The No SkyLine or Daylight distribution calculates the distribution of daylight across the room from the height of the working plane. For this, it is recommended that the view of the sky from the window adjacent to the proposed building should not be less than 80%.

Average Daylight Factor

The average daylight factor tells the average amount of daylight the room enjoys. Following the BRE Guidelines, different rooms in the house have unique ADF values and if each room meets its requirement, it is said to have adequate daylight.

Annual Probable Sunlight Hours

With the earth’s movement and change in seasons, the duration of sunlight varies with months. The annual probable sunlight hour is a measure of the total amount of sunlight that reaches the ground in a year. Therefore, there must be at least a window that receives at least 25% of the annual probable sunlight even during the winter months.


Overshadowing shows how much shadow is cast in the room from adjacent objects such as trees or buildings. To compute this, about half of the garden or open space in the property should receive at least two hours of light on 21st March.

Daylight and Sunlight Assessment Cost

The cost of a Daylight Assessments Dorking London depends on the surveyor you are having. Usually, several factors such as the size of the proposed building, and the number of the surrounding buildings affect the prices. You could also be charged based on the work hours.