The historic Kent County Administration Building in Grand Rapids, Mich., began its road to renovation with a new roofing system specified to replace an aging modified bitumen roofing system.

The historic Kent County Administration Building in Grand Rapids, Mich., began its road to renovation with a new roofing system specified to replace an aging modified bitumen roofing system.

The original modified bitumen system featured “Calder on the Roof,” a colorful abstract painting created in 1974 by well-known sculptor Alexander Calder to complement his “La Grande Vitesse” sculpture located in the adjoining plaza. The painting, which covers the roof of the administration building and can be seen from the upper floors of the surrounding buildings, had weathered severely and was in need of restoration. Due to the poor condition of the existing roofing system, a complete tear-off was required.

Re-roofing the local landmark presented several challenges, including:

• Limited access - The building is located in a busy downtown area near the Gerald Ford Museum, Public Museum of Grand Rapids and two major expressways.


• No interruptions - The project needed to be completed with no interruption to the busy plaza.


• The cleanliness factor - With the Calder Plaza below and many buildings overlooking the plaza, cleanliness was a top priority.


• Featured artwork - The building features a colorful abstract painting that covers the entire length of the roof.


• Time frame - The entire project needed to be completed in three weeks before the start of Art Prize, the first-of-its-kind open art contest that would take over downtown Grand Rapids.

A Unique Project

“The Kent County Administration Building project was very unique,” said Kevin Clausen, vice president at Great Lakes Systems, Inc. “While most projects usually present a challenge or two, there were several complicated aspects of this project that needed to be addressed simultaneously. The most important thing was that it needed to be completed within three weeks, and a project like this typically takes double that amount of time to complete.”

Seeking a balance of high performance and cost effectiveness, a fully adhered 60-mil Firestone RubberGard EPDM roofing system was selected to replace the aging modified bitumen system. Firestone RubberGard EPDM was chosen not only for its durability and ease of installation, but also because it provided a suitable painting surface to recreate the original Calder design. Other key components of the new, 18,500-square-foot roofing system included two layers of 2-inch Firestone ISO 95+ polyiso insulation and the use of Firestone AcryliTop PC-100 Base Coat over the EPDM membrane to provide a consistent surface for the new painting.

The Calder Plaza area is a downtown Grand Rapids focal point and is used as a stage for many festivals and events. The plaza name is derived from its home to the Calder stabile “La Grande Vitesse” - a well-known icon for the city of Grand Rapids. The re-roofing project needed to be completed with no interruption to the busy plaza and with no damage or marks to its finished concrete surface.

“Our task was to re-roof the building without actually accessing it and to do it as quietly as possible. To accomplish this, we devised a plan that would allow us to stage and coordinate our deliveries and be very quiet and clean while doing so,” Clausen said. 

Utilizing a Grove TMS 750 50-ton crane with 170 feet of boom to reach from Monroe Avenue NW directly to the rooftop, all loading was done on a daily basis, as was the removal of the existing modified bitumen roof system and original coal tar pitch roofing base. The tear-off debris was loaded into custom made steel cribs that were lifted from the roof and unloaded into dumpsters at the base of the crane set-up location on Monroe Avenue. With the Calder Plaza below and many buildings overlooking the plaza, cleanliness was as high a priority as the quality of the installation. With the inaugural Art Prize Open Art Contest scheduled to take place in downtown Grand Rapids, Great Lakes Systems was given just three weeks to complete the project. Setting a goal of two weeks to complete the roof installation allowed one week for the mural painting.

The aggressive timeline required removing and replacing approximately 2,000 square feet of roofing each day. Two layers of 2-inch polyiso insulation were adhered to the concrete deck using Firestone’s I.S.O Spray adhesive. The insulation was adhered in lieu of mechanically fastened in order to minimize noise, thus allowing the administrative work of the County government to continue without interruption. Once the insulation was installed, the new 60-mil Firestone RubberGard EPDM membrane was fully adhered in place. 

After proper cleaning and prepping of the membrane, Firestone’s AcryliTop base coat was applied, followed by a layout of the grid for painting the Calder mural over the membrane. The AcryliTop White top coat was used for all white areas, while a custom acrylic paint was used for the red areas. Each color was carefully applied within a confined grid in order to precisely match the original Calder design. The painting is believed to represent the largest Calder mural in the world.

“Re-roofing the Kent County Administration Building was an important and urgent need for the county. The project was completed beautifully within a condensed period of time, thanks to the great work of everyone involved,” Clausen said. “The county has been a great client of ours for years and we truly enjoy working with them.”

For more information, visit www.firestonebpco.com.

Just the Facts

Project: Kent County Administration Building

Location: Grand Rapids, Mich.

Contractor: Great Lakes Systems, Inc.

Contractor Location: Jenison, MI

Retrofit Products:

• Fully adhered 60-mil Firestone RubberGard EPDM


• Firestone AcryliTop PC-100 Base Coat


• 2 inches of Firestone ISO 95+ polyiso insulation