Background Architects, Get Planning, enlisted the support of Base Energy to carry out an external daylight assessment and sunlight study at the 1 Duppas Hill Terrace site in Croydon, which would see the construction of 10 new build self-contained flats. The Story Base Energy was brought on board after Croydon Council requested an expert Daylight Report be submitted with St Marc’s planning proposal, in order to understand the extent of any potential impact to neighbouring properties. There were concerns that the daylight levels of surrounding residences may be affected by the resurrection of the new flats due to the close proximity of the buildings. The adjacent development had three windows on the south façade, which faced the new site, so there were fears these windows may suffer an unacceptable reduction in natural light as a consequence. The Solution Our specialist consultants created a complex 3D model of both the existing and proposed sites to assess the daylight levels using a method called the ‘Vertical Sky Component’ This type of analysis allowed our team to compare the amount of available light that falls directly on the centre of an opening. If the opening retains at least 80% of its former daylight level, then it is deemed acceptable. The model showed that all three windows facing 1 Duppas Hill Terrace retained more than than 80% of their former daylighting levels. Our report concluded that the development met the recommended levels in line with the BRE 209 digest guidelines and is therefore considered compliant from a planning perspective. This meant that the project was able to go ahead without the worry of facing any objections to planning.