Salk Institute

Kahn's travertine-paved courtyard at the Salk Institute is a lesson in restraint. A single channel of water runs the length of a plaza paved in Roman travertine, framed by concrete laboratories and open to the Pacific. The stone does most of the work.

The travertine weathers to a silver-warm tone under salt air and direct sun, and the open-pore finish resists slip without looking rustic. It is a useful reference for any scheme involving large external paved areas near water or coastline.

Specifiers evaluating travertine for external paving should ask about density, frost resistance and pore filling. The right selection can sit outdoors for decades with only periodic cleaning.