Squaring Up An Angled Exterior

By on May 12, 2015

by Tom Finan, Executive Director, Construction Forum STL

The first up-close look at the angular walls and angled exterior panels on the new Shriners Hospital for Children that hugs the edge of The Grove Neighborhood invites many descriptive terms to the seasoned construction eye – daunting, impressive, and beautiful among them. Just don’t call them “diamonds.”

They are, the building’s designers say, “rotated squares”. That seems a trifle ironic given that 90-degree angles are in extremely short supply on Christner Inc.’s traffic-stopping design along the north edge of I64/40 at the corner of Clayton and Newstead on the BJC Healthcare campus.

The degree of difficulty proved a fitting test for the introduction of a “total enclosure,” single-source building envelope responsibility model being introduced in this area by IWR Building Systems. IWR is a subsidiary of MHS Legacy Group, a diversified national holding corporation also based in St. Louis, with roots back to 1895.

“IWR Building Systems had the responsibility of providing virtually the entire exterior building enclosure. The complex building skin of this project required a single source to successfully integrate the several exterior systems,” said George Crow of Heitmann & Associates, Inc. “Not only did IWR produce an aesthetically pleasing building exterior, but due to their attention to the interface details of the various systems, a building exterior was provided that will successfully manage water infiltration.”

The design called for the panels to be assembled with an unforgiving gasketed track rather than caulk in the joints and with the same gasketed joint rather than bull nose on the corners. One panel a hair out of alignment would prove disastrous down the row. Given those parameters, Keith Myers, executive vice president of MHS, credits the success of the project and the integrity of the completed envelope largely to the efforts of seasoned IWR Project Manager Mike Sheriff.

The new 90,000 sq. ft. facility will replace the existing Frontenac location. The building exterior consists of 3,600 rotated square Aluminum Composite Material (ACM) metal panels. S.M. Wilson was the general contractor on the project. IWR was responsible for the entire vertical exterior of the building. IWR’s sole subcontractor, Missouri Glass Co., installed the glass with IWR assuming responsibility for the glaziers’ work.

The panel system has been engineered with a pressure-equalized rain screen design which allows for a drainage cavity behind the panels. IWR undertook becoming the only sheet metal contractor in the St. Louis area certified by the Air Barrier Association of America (ABAA) in order to ensure the weather-resistance of the finished building envelope.

Sheriff noted that observers of the construction wondered why it took so long to begin erecting panels. The issue, he said, was making sure that IWR had the layout for the complex design absolutely perfect. Layout was particularly critical on elements such as the severely-angled arched window on the building’s southeast corner. Because they had only one chance to get it right, IWR laser-scanned the exterior of the building once the studs were in place.

They sent the data from those scans to Universe Corporation, which fabricated the panels and the mounting rails. On the extreme angles of the aforementioned southeast corner, the panels were actually folded in half.  Once the measurements were checked and the tracks in place, the panels went up with blazing speed. On the southern exposure (facing I40/64), “we installed 1,000 panels in four days,” Sheriff said.

IMG_4708 MHS Legacy’s Keith Myers said that  IWRs’ next test  of  their “total enclosure” services will be on the two 12-story medical towers that make up the first phase of BJC HealthCare’s Campus Renewal project on Kingshighway. If IWR’s efforts on Shriners are any indication, they’ll have angles covered there too.

Keith Myers points out corner detailing.

About Tom Finan