Repeating linear elements organised into arrays and lattices are commonly manifest in the work of Niall McLaughlin Architects. This paper describes a series of projects which explore the use of this ‘architecture of line’ in the work of the practice. Organised by formal development, rather than chronology, it identifies sequences that evolve from a two dimensional handling of line, as combs, to a thickened three dimensional handling that produces cat’s cradles, cages, naves, thickets and forests. The work of other architects, including Aalto Aalto, Kengo Kuma, Sverre Fehn, Peter Zumthor, Rudolf Schwarz and Karl Friedrich Schinkel, alongside the influence of Gottfried Semper’s writings, are placed within and alongside these sequences revealing common approaches and individual differences. Developed simultaneously through writing and drawing, the latter have been used to isolate elements of line within each architectural work, helping to understand their use and allowing a comparison to be made between McLaughlin’s work and the wider critical framework of other architect’s work. His particular spatial and temporal handling of line is revealed as a meteorological, environmental and poetic mediator between inner and outer worlds.