Give every room in which people spend time daylight from at least two sides; plan the building in narrow wings so that this is possible.
Rules · Cities · Light · Geometry
Space the rows by the winter sun
Set the gap between rows so that the shadow of each row at noon on the chosen winter day falls short of the glazed face of the row behind it.
gap = H ÷ tan α, with α = 90° − latitude − 23.4° at the winter solstice (at 48° N, α ≈ 18.6°: gap ≈ 3 H)
The rule is pure geometry, but it has large consequences for density. At Freiburg’s latitude the solstice shadow is three times the height of the obstruction, so designers either accept a later design day, lower the rows to the south, or put something that does not need sun (gardens, sheds, north-facing workspaces) in the shadow zone. In this town every gap is computed from the height of the row in front for the solstice at 48° N, and BedZED-type workspaces fill part of the shade.
Related rules
Shape the space between buildings as carefully as the rooms: make outdoor spaces partly enclosed and convex, like outdoor rooms, rather than leftover gaps around freestanding objects.
Frame a sphere by subdividing the triangular faces of an icosahedron and projecting the points onto the sphere; the triangulated net of short struts spreads loads through the whole surface and encloses the greatest volume for the least material.
full sphere of frequency ν: 30ν² struts, 20ν² triangles, 10ν² + 2 hubs
On an equator-facing window, make the overhang deep enough to shade the whole window from the high noon sun of summer, and no deeper, so that the low winter sun passes beneath it into the room.
noon sun altitude = 90° − latitude ± 23.44° · overhang D = window height ⁄ tan(summer altitude)
Make neighbourhoods compact, pedestrian-friendly and mixed in use, with a clear centre and edge, so that daily needs lie within a short walk: about a quarter of a mile, five minutes, from centre to edge.
centre to edge ≈ ¼ mile ≈ 400 m ≈ 5 minutes on foot
Lay out the rows east–west so that the long, glazed face of every house turns to the south (in the northern hemisphere), taking the low winter sun and shading easily from the high summer sun.
Cite this page Chris Paton, “Space the rows by the winter sun”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/solar-row-spacing. Text, drawings and models licensed under CC BY-NC 4.0.