Architect Notebook .... HOW IS IT MADE?

Tectonic display

Having established what the ‘carcass’ or bare bones of the structure will be, the designer will give further thought to how these ‘blocks’, ‘sticks’ or ‘membranes’ will be assembled and joined together. As we shall see in the next chapter, this process in itself allows the designer plenty of scope for architectural expression, for just as architects of the functionalist school decreed that the nature of the ‘carcass’ should receive attention as an expressive element, so did they tend towards the view that the nature of materialsmaking up the building’s envelope, and more particularly, the manner of their assembly, should also contribute to ‘reading’ the building.

The envelope

The majority of our constructional concerns relate to the design of the building’s external envelope; the walls and roof membranes and how these are pierced for lighting or access. Decisions about the nature of this external ‘skin’ to the building will not only interact with other major decisions as the design develops, but will also determine to a large extent how the building will look.

The roof

Take the roof for example; will it be flat or pitched, and in either case will it project beyond the wall plane to afford some protection from the weather or will it be arrested behind a parapet wall? Should the roof be considered as a lightweight ‘umbrella’ structurally and visually separate from the principal structural idea, or does that idea also produce the roof envelope merely by the application of a waterproof membrane.

These fundamental questions of whether the roof is a lightweight or a heavyweight envelope (with a considerable thermal mass) have real consequences regarding the building’s appearance but also its performance.

The facade

Like the roof, the wall membrane is an ‘environmental filter’ which contributes to the building’s performance and decisions regarding lightweight versus heavyweight, or permeable versus impermeable which applied to the roof likewise need to be considered. But in the case of walls these decisions assume a greater degree of complexity for, much more than roofs, walls tend to be punctuated by openings to provide access, daylighting, views out, or ventilation, all of which have to be accommodated within the strategy for construction.