M.G. McGrath used two pieces of material and a multi-step stamping technique to produce the crumpled-look expanded aluminum panels that cover the exterior of the Walker Art Center’s $67 million south wing addition. The project, located in Minneapolis, MN, and completed in May 2005, was designed by Pritzker Prize-winning architect Herzog & de Meuron of Basel, Switzerland. The project’s architect of record, engineer and landscape architect was Hammel, Green & Abrahamson of Minneapolis.

To create the five sizes of double-layered aluminum panels that cover the 130,000 sq. ft. addition, Maplewood, MN-based McGrath used a technique that required each piece to be rotated and stamped four different times. For the bottoms and sides of the resultant box-like panels, the architect specified 0.50”-thick expanded aluminum. For the surface sheet, a slightly thicker 0.80”-thick piece was used. Both have a Brite Dip clear anodized finish.

McGrath installed the nearly 3,000 panels—2,243 for the walls and 644 for the soffits—to a grid work of 2” x 4” anodized aluminum tubing. The sub-framing members were attached to the face of 2”-thick insulated metal wall panels.

Spantek Expanded Metals of Hopkins, MN, manufactured the diamond-pattern expanded aluminum. The project required 72,175 sq. ft. of the thinner gauge material and 47,000 sq. ft. of the thicker. Approximately 22,000 linear feet of the tubing was utilized, along with 36,892 sq. ft. of the insulated wall panels. The latter was manufactured by Metl-Span of Lewisville, TX.