The Fog house occupies a small manufacturing building typical of the area, with a steel and glass envelope standing inside the shell of the earlier building. The envelope projects above the shell, giving a view across Clerkenwell’s rooftops, and out of one end, towards the parish church whose churchyard has become a small park. The horizontal and vertical projections of the envelope take different forms. Apart from sharing a party wall, the living space occupies a free-standing pavilion with a long side positioned against a brick parapet. Due to a legal difficulty with constructing foundations at the end of the site, the horizontal extension involves a substantial cantilever. In elevation, the sides of the top floor and the horizontal extension are in the same plane. The plans explore the archaeology of the site, masking irregularities in some cases and developing them in others. The latter option is explored in the splayed plan of the top floor.
All of the windows in the shell have been re-glazed with translucent glass so that they admit light without giving a view. The intensity of light depends on the distance from the ground and the orientation of the windows and this is especially clear when using the MDF staircase which is situated on an outside corner and has windows in two directions. On each of the main floors, the translucent glazing makes a connection between the arrival point and the view towards St James’ church, which is framed in a different way at each level. A tendency to polarise the edges of each floor is most clear in the main living space: a panoramic view of the parish church contrasts with a telescopic view of nearby roofs, and a gentle splay on the party wall contrasts with the strict linearity of the new wall opposite. The precise colouring of this wall, and of the space, itself is dependent on external conditions. In bright weather, it glows with diffused light; at other times, the glass has a darker colour and the internal reflections describe a virtual space that has a mysterious depth. The effect of the solid parapet behind this wall is comparable to that of the horizon in a Sugimoto seascape.