In his classic book How Buildings Learn Stewart Brand highlights an idea by the British architect Frank Duffy:
A building properly conceived is several layers of longevity.
Duffy called these shearing layers. Each of the layers moves at a different timescale. Brand expanded on the idea, proposing six alliterative layers:
- Site—the physical location of a building only changes on a geological timescale.
- Structure—the building itself can last for centuries.
- Skin—the exterior surface gets a facelift or a new lick of paint every few decades.
- Services—the plumbing and wiring need to be updated every ten years or so.
- Space plan—the layout of walls and doors might change occasionally.
- Stuff—the arrangement of furniture in a room can change on a daily basis.
In a later book, The Clock Of The Long Now, Stewart Brand applied the idea of shearing layers—or pace layers—to civilisation itself. The slowest moving layer is nature, then there’s culture, followed by governance, then infrastructure, and finally commerce and fashion are the fastest layers. In a loosely‐coupled way, each layer depends on the layer below. In turn, the accumulation of each successive layer enables an “adjacent possible” filled with more opportunities.
From Jeremy Keith: Resilient Web Design