Formerly known as the Powerhouse Science Center, the Sacramento Municipal Utility District (SMUD) Museum of Science and Curiosity (MOSAC), transformed an abandoned riverfront structure into a regional hub for science, technology, engineering, art and math (STEAM) education, exploration and promotion.
New museum reimagines a historic riverfront power station
Located on the banks of the Sacramento River, the museum grows out of an abandoned PG&E River Station B power station building designed in 1912 in the Classical Revival style by architect Willis Polk. Formerly closed in 1954, the building is on the National Register of Historic Places, California Register of Historical Resources and the Sacramento Register of Historic & Cultural Resources.
A design-build project by Dreyfuss + Blackford Architecture, Sacramento, and Otto Construction, Sacramento, the 30,000-square-foot original structure underwent a complete historic rehabilitation and construction of a new floor level inside. A new two-story, 22,000-square-foot addition was added to the east side and contains a lobby, classrooms, offices and a café. A 120-seat planetarium features a zinc-clad hemispheric dome sits atop the northwest corner of the new addition.
For the domed addition to the LEED Platinum-certified project, Otto Construction said a base steel ring needed to be positioned exactly at a 5-degree tilt and a 5-degree rotation. The roof consists of structural steel, double light-gauge metal framing walls, a layer of fiberglass mat gypsum roof cover boards, and two layers of plywood covered by RHEINZINK AIR-Z matting and the prePATINA tiles.
The dome features 4,166 square feet of prePATINA zinc tiles in Graphite-Grey from RHEINZINK America Inc., Woburn, Mass. Clad in 1,570 tiles, the 0.8-mm-thick zinc flat-lock panels in a trapezoid shaped are installed in a running bond pattern.
Louie Rua, president of metal fabricator and installer Rua & Son Mechanical Inc., Rocklin, Calif., says each row is a little different. “First, we used CAD to visualize the layout on the screen. Then, we worked with Otto to build a 20-by-20-foot physical mock-up that replicated the dome about half-way up. These models allowed us to play with the panels’ thickness, sizes and dimensions. This helped us make sure they didn’t oil can and were not too small at the top or bottom.”
According to Rua, his team used computerized folding and shearing equipment, and the panels range from 32-inch by 18-inch on the bottom of the dome to 9-inch by 18-inch panels on the top. “They worked together in sequence, row by row, from bottom to top,” he explains. “At the end of the row, a specially formed, interlocking panel zips them together at the back so everything matches. The zinc panels went on flat and tight for a smooth, symmetrical appearance. It turned out great.”
“The design called for metal with a natural look,” adds Rua. “Zinc delivers the natural look and patina, and its soft pliability takes the shape of the roof better and really hugs the curve.”