The Sun Valley Slider

The Sun Valley Slider is from the high point of American sliding door design — the early 1970s, when ski lodges and ranch houses wanted glass walls and the manufacturers responded with extruded aluminum frames that have outlasted three generations of vinyl replacements. The bronze track is the secret. Aluminum tracks pit and bind. Bronze does not. This door slides with one finger after fifty-three years.

The sliding patio door reached its design peak between 1968 and 1976, and almost all of them were thrown away during the 1990s “energy efficiency” replacement wave. The Sun Valley Slider survived because the lodge owners had it serviced annually instead of replaced.

The bronze track is the thing. Aluminum track is cheaper and lighter, but aluminum is soft and bronze is hard. After a few years, an aluminum track develops shallow pits where the rollers dwell — and the rollers stop being smooth, and the door binds. Bronze track does not pit. The Society has measured this door’s track at 0.003” of wear over a 90-inch span. Negligible.

The single-pane tempered glass is the part most modern eyes will object to. We acknowledge that it is not energy-efficient. We point out that the door’s R-value (~1) is the floor, and that adding a thermal insert behind it during cold months has gotten the lodge’s heat load down to acceptable. The original glass has been in the frame for fifty-three years and has never broken. The replacement double-pane unit would be sealed for fifteen.

The Society is not opposed to insulation. The Society is opposed to throwing away functional objects in service of marginal efficiency gains.