1A ‘Within’ Assessment
This is an assessment to see whether your new development (usually residential in nature, for example, new housing, flats or student accommodation) will be able to enjoy good daylight and sunlight following completion. Thus, it seeks to assess your own scheme, and has consideration of things such as room layouts, window glazing, and internal reflectance values of wall, floor and ceiling finishes.
If you can demonstrate through a Daylight and Sunlight Assessment that your new development will enjoy good conditions, then this is more likely to contribute positively to the approval of the scheme.
If however the new design cannot demonstrate a good level of daylight and sunlight to the Local Authority, they can ask you to adapt your scheme so as to improve such conditions. This can lead to a delay in getting your scheme validated, as any amended design will normally have to be re-assessed to demonstrate an improvement to the planning officer.
Failure to address such matters can result in a scheme being refused planning permission.
2A ‘Neighbouring’ Assessment
If your new development is situated close to other nearby properties, the Local Authority might be concerned that your scheme may have an adverse impact upon the daylight and sunlight currently enjoyed by such properties. This is especially so if the neighbouring buildings are residential in nature.
You may be asked to assess this risk, sometimes even before your application will be validated.
This type of report seeks to assess the amount of daylight the neighbours’ windows are capable of achieving, and, if a neighbours’ room layout is known, it may also seek to demonstrate how the daylight is distributed within the neighbours’ room. The tests also seek to assess how much sunlight the neighbours’ windows will get over the course of the year, and, how much sunlight they will get in winter months.
The other aspect sometimes considered here is the impact that the new development may have upon overshadowing to the neighbour’s principal outdoor amenity and garden areas.
Often one of these reports can assist with a planning application if it can demonstrate low impact upon neighbouring properties. Indeed, sometimes, because of demolition of existing site structures, improvements to conditions serving neighbouring properties can be demonstrated.