pearl control house

The Pearl Substation was constructed at the tail-end of Bonneville Power Administration’s system build-out in the late 1960s. Thirty years after the original cast-concrete industrial building styles that fit naturally next to a 20 story dam were built, they are now old-fashioned. Instead the control house looks more like a post-war international style pavilion. Building volumes are low and extended out. Vertical medium blue asbestos board panels wrap the programmatic boxes of varying heights, emphasized with silver aluminum battens. A perfectly flat roof steps back from the blue walls trimmed in bright aluminum.

BPA treats all its buildings completed during its thirty plus years of initial construction as having the potential to be listed on the National Park Service’s National Register of Historic Places. Though its exterior panels were badly faded and stained and a cheaply fabricated office area was added 30 years later, further renovation and addition of the building required review by the state historic preservation office (SHPO). To further its life the building needed seismic strengthening, energy efficiency upgrades, modifications to the flat roof to ensure positive drainage and removal of the existing asbestos siding. Because of expansion of the substation the control room itself required an addition to double its size. All this needed completion while maintaining the original appearance and character of the building.

Aluminum composite wall panels were chosen to replace the original asbestos in a similar blue color. To contrast the original building with the new construction the layout and proportions of the panels are changed and the height of the addition is increased. Needing to add height to the existing building to achieve new slopes to the roof drains, an additional step back in the fascia maintains the original profile of the building mass. Finally the original building window styles are retrofitted into the office addition to eliminate its stark contrast to its mate.