HDR was commissioned to assist Unilever in the relocation of approximately 400 employees to their campus at Englewood Cliffs, New Jersey. Work included a full renovation and repurposing of 236,000 SF of 1970?s vintage office space, as well as 24,000 SF of new construction. Although the basic framework of the campus has remained successful over the years, the buildings themselves along with site development were out-dated and in decline. A major renovation of the facilities would be required to support the consolidation and maintain the Unilever Headquarters image. The green roof project was an outgrowth of updating the facility and promoted Unilever?s proactive stand on sustainability.

The Unilever Green Roof Project is a 16,000 SF membrane roof retrofit over a 4-story office building (Building ?B?). 13,000 SF of the green roof resides over the 3rd floor and the remaining 3,000 SF resides between two open atriums over the 2nd floor. The existing roofs were leaking and showing signs of deterioration and needed to be replaced. The client desired a roofing system with a pleasing appearance, considering its high level of visibility from adjacent conference room space. The roof was to be a visual amenity only, not accessible to building occupants.

Specific project challenges involved:

– High visibility from adjacent conference and executive office space
– Existing railings that did not meet current building codes
– Existing roof leaks
– Minimal roof slope
– Concrete waffle slab structure
– Existing load capacity

A new ?Hydrotech? monolithic membrane system with an extensive ?LiveRoof? pre-vegetated tray system was implemented. The ?LiveRoof? system is composed of recycled plastic trays filled with lightweight growing media and populated with a variety of Sedum plant material. The tray design allows for uniform root growth and drainage over the entire roof surface. Metal edging and riverstone ballast around the perimeter was utilized, along with the weight of the trays themselves, to prevent wind uplift of the trays. In order to accommodate these systems, the team decided to remove and replace all existing roofing components down to the slab, as well as existing drainage structures, railings and parapet wall copings. A safety cable and harness system was installed to adequately protect workers maintaining the green roof.

Specific Construction Details:

– Greenroof System: LiveRoof (1?x2?x4? pre-vegetated modular trays)
– Growth media type: LiveRoof Engineered Green Roof Soil ( 94+% inorganic material)
– Waterproofing System: American Hydrotech (hot fluid-applied reinforced waterproofing/roofing membrane system)
– Rooftop Paver System: Hanover Architectural Products (2? sq. Rooftop Pedestal Pavers)
– Edge Restraint System: Permaloc Corporation – aluminum edge restraint
– Building/Roof Height(s): 2-story and 3-story
– Plant material (provided by Creek Hill Nursery): Delosperma Cooperi, Sedum ‘Album’, Sedum ‘Angelina’, Sedum ‘Bertram Anderson’, Sedum ‘Blue Spruce’, Sedum ‘Coral Carpet’, Sedum ‘Dasyphyllum Major’, Sedum ‘Fuldaglut’, Sedum ‘Green Spruce, Sedum ‘Kamtschaticum’, Sedum ‘Red Carpet’, Sedum ‘Sexangular’, Sedum ‘Sieboldi’, Sedum ‘Ternatum’, Sedum Tricolor, Sedum ‘Weihenstephaner Gold’
– Length of construction: May 2009 ? Nov 2009