The decks and railings at the House on Hummingbird Hill are meant to last. Much of the idea was to have as close to a maintenance-free house as the Weingartens could get: no re-painting, no re-staining, no replacing.
Trex is a well-known deck material made of ground-up wood and recycled plastic. It’s rot-proof and termite-resistant. Pretty much indestructible. It’s also more expensive than wood. But this was a place where spending a little more in the beginning would save a lot later on. Life-cycle thinking at work.
At the same time, the Weingartens found a way to spend less and get more, and that is the Trix part of this equation. The outside railings are made of galvanized piping and steel concrete-reinforcing bar. Those cost less than redwood, but will not require upkeep or replacement for a hundred years or so.
The Weingartens also used Trex for exterior trim elsewhere on the house.