How Buildings Learn

Stewart Brand, 1994

Buildings change. The best ones are designed to accommodate that change. The worst fight it.


Brand studied what happens to buildings after they’re “finished” — which is to say, after architects stop paying attention. The answer: they evolve. Walls get moved. Additions appear. Uses shift. The building its designer intended and the building that actually exists are rarely the same.

Shearing Layers

Brand’s most useful concept. Every building is actually six systems, each changing at a different rate:

  1. Site — geographic setting (changes on a geological timescale)
  2. Structure — foundation and load-bearing (30–300 years)
  3. Skin — exterior surfaces (20 years)
  4. Services — wiring, plumbing, HVAC (7–15 years)
  5. Space plan — interior layout (3–30 years)
  6. Stuff — furniture, possessions (daily to monthly)

The principle: design each layer so that faster-changing layers can change without disrupting slower ones. Don’t embed wiring in load-bearing walls. Don’t make the floor plan depend on the facade.

This applies to software, infrastructure, organizations, and households. Thistlebridge’s architecture has shearing layers: the hardware changes on a different cycle than the knowledge base, which changes on a different cycle than the daily session protocol.


Connections


“A building is not something you finish. A building is something you start.”