Durability

The stage

Durability is the last stage and the longest. It asks whether the building is still useful, and still wanted, long after everyone who built it is gone.

What the usual way assumes

That thirty years is long enough. Houses in a growing city are rarely torn down because they are worn out. They come down because they can’t become what their land now allows.

What we do instead

Build for the weather we have. In a wet climate that means cladding with an air gap behind it, deep overhangs and careful flashing.

Build for the next change. An old rule from 1972 says it well: long life, loose fit.¹ Structure and pipes are sized for a later floor or a split into two homes. Rooms aren’t tied to one use.

Plan for the day it comes apart. Fasteners are chosen for removal as well as installation: hex or square heads a wrench can still grip in sixty years, metals that won’t rust together, nothing in a drive pattern that may not exist by then.

A fastener you cannot buy a driver for in 2085 is a nail.

What we don’t know yet

Whether reversible joints stay reversible. Wood shrinks onto screws, paint fills the heads, metals seize. Nobody has sixty years of evidence on these details, including us.

Sources and notes

1. Alex Gordon, president of the Royal Institute of British Architects, “Long life, loose fit, low energy,” 1972. ↩