Historic power plant converted to modern offices in Minnesota

A landmark power plant in Owatonna, Minn., damaged in a 2010 flood has new life as the headquarters of Owatonna Public Utilities following a renovation by architects Leo A Daly.

When the Straight River flooded in 2010, 12 feet of water stood in the basement of the Owatonna power plant, a brick Italianate building with a distinctive neon sign, arched windows, and three silver smoke stacks. The flood damaged its generators, but OPU sought Leo A Daly's help in re-purposing the building into its new headquarters.

The interior volume of the turbine hall — 50 vertical feet of open space that had previously accommodated the plant’s massive boilers — guided Leo A Daly’s approach to space planning for the administrative and customer service spaces that would occupy the building.

Using the interior steel structure as scaffolding, Leo A Daly laid out atrium spaces and floating offices that cantilever over the ground floor. The effect is a series of connected spaces all lit by daylight through the building's large windows.

The building integrates artifacts from its pre-flood days. Boiler doors, valve covers, and valve wheels are re-presented in a gallery space. Bar grating is reused in the new building as railings. Energy efficient windows were installed while keeping the original window framing and some of the original glass in place. Colors, textures and materials from the original floor and equipment are incorporated.

To prevent future flood damage, flood doors were installed in a conditioned space below the flood line, which will allow river water to come and go without disrupting operations above. To pull this off, the architects had to raise the first occupiable floor by one foot.

Leo A Daly sees the Owatonna renovation as part of a growing trend. More cities are interested in repurposing their heritage facilities, rather than simply razing them and building new.