Shadow study
A shadow study calculates how sun and shadow fall across a property and the surrounding buildings through the day and the year. Sun and shadow conditions are one of the strongest value drivers for homes, and most municipalities require sun and shadow diagrams as an attachment to zoning plans and framework applications for housing projects.
The technical terms are sun and shadow diagram, or shadow analysis. The diagrams are normally produced for the spring equinox (21 March), the summer solstice (21 June) and the autumn equinox (23 September) at fixed times such as 09:00, 12:00, 15:00 and 18:00. Many municipalities add a requirement that shared outdoor areas must have at least five hours of sun at the equinox to count as satisfactory. Requirements for daylight and outdoor areas come from the building regulations byggteknisk forskrift TEK17 published by Direktoratet for byggkvalitet (the Norwegian Building Authority), in particular section 8-3 (Uteoppholdsareal, outdoor areas) for sun and daylight on shared outdoor space and section 13-7 (Inneklima og helse, indoor climate and health) for indoor daylight, supplemented by the Planning and Building Act and municipal planning provisions.
The calculation is based on the height and azimuth of the sun for the latitude of the site, terrain from the national elevation model held by Kartverket, and a 3D model of existing and planned buildings. Norwegian latitudes give low sun angles in winter and therefore long shadows that often set the limits for the project, both for the design of outdoor space and for the placement of flats. Standardised calculation methods are described in, among others, SINTEF Byggforskserien (guidance 471.011 on sun and daylight), and the results are usually presented in a site plan, facade elevations and a 3D rendering for the planning case.
For a developer, a shadow analysis is both a planning tool and a documentation requirement. Early in a feasibility study it helps you place volumes and set the number of storeys so that your own outdoor areas and the neighbours' sunlight are protected. In the framework application, the diagram is often the key document that lets the building control department accept the TEK17 requirements as met.
In Placepoint you can calculate sun and shadow for a planned building volume as part of a 3D volume study, and use the result together with sight lines in the early project phase.
How this looks in Placepoint
In Placepoint you find this in 3D-Designer:
From the Placepoint glossary: Shadow study
More information: DiBK: TEK17 section 13-7 Lys (Inneklima og helse), SINTEF Byggforskserien, Store norske leksikon: solinnstråling
English: Shadow study (sun and shadow analysis).
Frequently asked questions
What is a shadow study?
A shadow study is a calculation that shows how sun and shadow fall across a property and the surrounding buildings through the day and through the year. The result is presented as sun and shadow diagrams for selected dates and times.
When is a shadow analysis required in a building case?
Most municipalities require sun and shadow diagrams as an attachment to zoning plans and framework applications for housing projects. The requirement comes from TEK17 section 8-3 (Uteoppholdsareal, outdoor areas) and section 13-7 (Inneklima og helse, indoor climate and health), and municipal planning provisions can add requirements for a minimum number of sun hours.
What is the difference between a shadow study and sight lines?
A shadow study calculates sun and shadow conditions based on the path of the sun and the height of buildings, while sight lines concern the horizontal view from a point. Both are used in early project assessment, but they answer different questions.
Which dates are normally used in a shadow analysis?
The standard dates are the spring equinox (21 March), the summer solstice (21 June) and the autumn equinox (23 September), usually at times such as 09:00, 12:00, 15:00 and 18:00. Norwegian latitudes give low sun angles in winter, and the summer solstice diagram is normally the most favourable one for the project.