System of manufactured units assembled on site. Also called system building.
Infill
In timber-framed construction, the non-structural material that fills the compartments, e.g. wattle and daub, lath and plaster, brickwork (known as nogging), etc.
Inglenook
(lit. fire-corner): Recess for a hearth with provision for seating.
Ingo
(Scots): The reveal of a door or window opening where the stone is at right-angles to the wall.
In situ
Of concrete, cast in position on the building.
Intercolumniation
Interval between columns.
Interlace
Decoration in relief simulating woven or entwined stems or bands.
Intersecting tracery
A type of bar tracery used c. 1300, formed by interlocking mullions each branching out in two curved bars of the same radius but different centres.
Intrados
Inner curve or underside of an arch.
Ionic
One of the orders of classical architecture, distinguished in particular by downward- and inward-curling spirals (called volutes) on the capital of the column.