DENVER, CO--(Marketwired - Apr 12, 2016) - Office properties contend for tenants by offering amenities in an attractive combination of recreation, retail, and relaxation options. On Prudential Plaza, a 41-story structure in Chicago, owners envisioned a top-to-bottom rehabilitation, featuring a 13,000 sf amenities deck with an amphitheater, fire pit, and lawn.
The challenges of adding this type of space on top of a 60-year-old roof are immense. Wolff Landscape Architecture project manager Ishmael Joya, however, understood adding a mini-park to a four-and-a-half-inch thick roof deck was going to require out-of-the-box thinking.
"The building is only designed to support a maximum amount of weight," said Joya. Fortunately, he'd already had a strong positive experience with ACH Foam Technologies' Foam-Control® EPS Geofoam, a lightweight expanded polystyrene (EPS) material with high compressive strengths used to reduce axial loading.
Prudential 's renovation used Geofoam EPS 15 in areas that would be filled with plants and Geofoam EPS 46, chosen for its exceptionally high compressive strength in areas that would bear more weight of the roof deck occupants. For Joya, another great advantage of using the EPS Geofoam is seeing the shape of the assembled product and making adjustments before the concrete is poured. Once construction was underway, installing the Geofoam was the responsibility of Christy Webber Landscapes, a subcontractor with extensive experience with green roof construction. One challenge was getting the building materials to the 11th-floor. Since the building is located adjacent to a series of vaulted streets, the construction team wasn't able to use a high reach crane because the weight of the crane would have necessitated street closures.
"We worked with ACH Foam Technologies to have the foam cut to a specific length allowing it to be carried to the roof through the building's freight elevator," noted Kinsella. ACH Foam also developed a just-in-time delivery schedule ensuring a steady stream of EPS Geofoam arrived on the roof as workers were ready allowing them to keep the limited staging area clear of excess material.
The transformation of the 11th-floor roof deck really couldn't be more dynamic. The space went from a flat, barren roof to a vibrant, inviting private park.