Cool beans

• Photo courtesy of Preservation Services Inc., Romeoville, Ill.
• Photo courtesy of Preservation Services Inc., Romeoville, Ill.
• Photo courtesy of Preservation Services Inc., Romeoville, Ill.
• Photo courtesy of Preservation Services Inc., Romeoville, Ill.

The aquatic animals that fill the tanks at John G. Shedd Aquarium in Chicago may have thought something fishy was going on during the past year. Helicopters frequently flew around the building at the crack of dawn, and a big deal was being made about the roof.

And with good reason. This was no ordinary roofing project. The aquarium's new roof system was surfaced with a soybean-based ELMS,® or Environmental Liquid Membrane System, which was manufactured by Green Products LLC, Romeoville, Ill., and installed by NRCA member Preservation Services Inc., Romeoville, Ill.

The amount of ELMS applied to the roof system was equivalent to oil taken from 37 acres of soybeans.

Planting the seed

As an eight-year service contractor for the aquarium, Preservation Services had been aware of a growing need for a new roof system on the structure. To continue the aquarium's energy-conservation and environmental initiatives, Facility Director Brad Popovich wanted to use the most environmentally friendly and energy-efficient components possible when replacing the roof system, which meant hot asphalt was not an option because of fumes it could release.

Because of its existing relationship with the aquarium, Preservation Services was asked to perform the job in several phases. The company needed to remove and replace 1,300 of the original skylights from 1929, as well as restore the Oceanarium's original APP-modified bitumen roof system installed in 1987. The 1991 Hypalon® membrane over the west entrance needed to be restored, as well, and Preservation Services was asked to remove the existing roof system and install a Green Products roof system on the main roof area. Where possible, restoration options were selected for financial and environmental reasons. The aquarium chose to restore the roof systems on the Oceanarium and west entrance to reduce contributions to landfills that roof system removal would cause.

The main section of the original roof system is 52,500 square feet (4877 m²) and consisted of a concrete panel deck, single layer of 15/16-of-an-inch- (24-mm-) thick fiberglass insulation, and an APP-modified bitumen membrane roof system. The Oceanarium's roof is 85,615 square feet (7954 m²) and consisted of a wood deck, 2-inch- (51-mm-) thick polyisocyanurate insulation, 1-inch- (25-mm-) thick perlite board and an APP-modified bitumen membrane. The west entrance's roof is 6,600 square feet (613 m²) and consisted of 2-inch- (51-mm-) thick polyisocyanurate insulation and 45-mil- (1-mm-) thick Hypalon membrane. All were mechanically fastened to a concrete deck.

Watching it grow

Removal of roofing materials took about three months, beginning in the northwest and moving clockwise around the circular facility. Complicated by the staging required to remove debris from the roof, multiple helicopter lifts were needed to hoist material and debris.

To supplement energy objectives and amplify the distribution of natural light to the Shedd Aquarium's sea creatures when replacing the skylights on the roof, Preservation Services installed skylights that featured prismatic lenses.

In addition, the original roof system on the Oceanarium needed repairs.

"The original APP-modified bitumen membrane previously had been coated with a white acrylic product that had deteriorated badly and easily was removed as a part of the normal surface preparation," says Jeff Graf, vice president of operations for Preservation Services. "After the surface was repaired and power washed, the roof was surfaced with a single coat of ELMS 50 made for built-up and modified bitumen roof systems. ELMS is a low-permeability liquid membrane produced from proprietary soy-based polymers that replaces typical petroleum-based constituents found in most roofing products.

"ELMS is the scientific result of advanced bio-based technology that provides proprietary polymers extracted from the soy oil byproducts generated from the food industry," Graf continues. "As natural oil-based material, the ELMS line of products is capable of replacing many petroleum- or solvent-based products."

The restoration of the west entrance and installation of the main roof area also included the use of ELMS.

"The west entrance Hypalon membrane roof system was upgraded with fastener and seam repairs, followed by a single-coat application of ELMS 150 liquid membrane designed for restoration and waterproofing of aged single-ply roof systems," Graf says.

On the aquarium's main roof system, Preservation Services removed the existing APP-modified bitumen membrane and fiberglass insulation on the concrete panel deck and installed a new vapor retarder to the primed deck. The crew then installed in adhesive 3-inch- (76-mm-) thick polyisocyanurate insulation, 1/2-inch- (13-mm-) thick re-cover board made from 95 percent recycled materials, two plies of APP-modified bitumen membrane and ELMS surfacing.

Tearing off

The tear-off process and safety precautions were tailored specifically to this complicated project.

"Given the challenging logistics complicated by the maze of skylights, mechanical equipment and limited access because of the building's lakefront location, a 10-foot- (3-m-) high elevated platform with safety railing was erected to circumnavigate the perimeter," Graf says. "Saturated roof debris was staged in disposal bags that ultimately contained 3,000 pounds (1361 kg) of waste."

Because the bags could not be moved and would drain water onto the work area, roof areas strategically were removed in advance and a vapor retarder was installed to accommodate the bags' location. Bags would drain for hours and had to be stored on the roof in individual plastic pools. Empty bags were placed in the pools in the prepared areas, and debris was placed in the bags during demolition. As water drained into the pools, a vapor retarder was installed, and the pools then were sliced and allowed the water to drain on the watertight membrane. More than 200 pools were used.

Preservation Services developed well-sequenced hoisting schedules to remove the bags and make the best use of the helicopter flight time, which only could be used from daybreak until 8:45 a.m. because of the aquarium's hours of operation, Graf says. To maximize flight time, Preservation Services established staging areas near the south entrance, and material was brought in and secured the night before a planned lift.

"On the day of a lift, new material was brought up and staged on a platform or on the deck," Graf says. "On the return trip to the staging area and dump, a 3,000-pound (1361-kg) reinforced bag of debris was taken and lowered into awaiting trash bins. About 190 of these bags were lowered and five semi-loads of material were moved using the helicopter service. Four such lifts were required supplemented with night-crane hoisting for the west entrance area."

Rough waters

The complicated process prompted Preservation Services to implement special safety precautions. The project required a thorough flight plan, weather checks, time-specific permits and coordination with Chicago police to accommodate security and traffic concerns. Before helicopter lifts, Popovich would notify neighboring buildings on the Museum Campus, such as the Field Museum of Natural History and Adler Planetarium, as well as The Chicago Park District. Harnesses and lanyards were used at all times when workers were outside perimeter warning systems placed on the Oceanarium and west entrance roof areas, and the main roof area contained an elevated platform with 4-foot (1.2-m) safety railing inside and out.

Safety issues were not the only challenges faced and overcome.

"The complicated logistics on the roof and at the pedestrian level were solved with the highly coordinated helicopter lifting," Graf says. "In the morning, at ground level, the lakefront is active with bikers, walkers and joggers, all of which needed to be diverted from the hoisting area and flight path. And because the project involved live animals sensitive to the smallest deviation in the environment, there was extensive crew orientation as to the delicate and unique needs of this facility."

Going swimmingly

These complicated and sensitive issues, as well as the environmental and energy initiatives, made the project stand out.

"Being a part of this groundbreaking project on one of Chicago's premier landmarks and the world's largest aquatic facility made this project unique," Graf says. "Participating in what we foresee as the future of the roofing industry and introducing the use of bio-based roofing products made from agricultural oils designed to replace petroleum products has been the most rewarding part of the project."

Krista Reisdorf is associate editor of Professional Roofing magazine.

Project name: John G. Shedd Aquarium
Project location: Chicago
Project duration: February 2004-October 2004
Roof system type: APP-modified bitumen coated with an Environmental Liquid Membrane System membrane
Roofing contractor: Preservation Services Inc., Romeoville, Ill.
Roofing manufacturer: Green Products LLC, Romeoville, Ill.
Roof consultant: MacBrady & Associates, La Grange, Ill.

Setting an example

During its work on the John G. Shedd Aquarium, Preservation Services also installed a prototypical roof assembly on a roof area contained within the confines of the main roof area. The prototype is meant to promote the variety of bio-based materials available through Green Products.

"This is the first roof system of its type to showcase bio-based technology and its effect on the roofing industry's future," says Jeff Graf, vice president of operations for Preservation Services Inc., Romeoville, Ill.

The system consisted of 1 1/2-inch- (38-mm-) thick rigid insulation made from soy-based polymers and is 75 percent bio-based, as well as a recovery layer of recycled re-cover board. All insulation was adhered with a two-part, 70 percent bio-based, low-rise foam adhesive, and a three-ply membrane system with bio-based polymer interply and fiberglass reinforcement was installed. Finishing off the system was surfacing that consisted of embedded ceramic granules in ELMS coating and an additional application of ELMS at 1 gallon per 100 square feet (0.4 L/m²) to seal the granules.