When the City of Minneapolis needed to replace
the nearly two-decades-old roof of the Target
Center, the Upper
Midwest’s premier entertainment facility, it took a decidedly
progressive approach.
When the City of Minneapolis needed to replace
the nearly two-decades-old roof of the Target
Center, the Upper
Midwest’s premier entertainment facility, it took a decidedly
progressive approach. It replaced the arena’s aging roof with a vegetative
roof, bringing a long-life, ecological solution to the facility in the heart of
downtown Minneapolis.
And for a high performing, versatile coverboard that would match the innovation
of the project, Stock Roofing Company selected Georgia-Pacific DensDeck® Prime
Roof Board due to its proven history, strength and reputation for superior
performance. Not only was DensDeck Prime Roof Board used as a cover board in
the roof assembly beneath the vegetative roof, but also in the roof assembly of
the Target Center’s 29 non-vegetative smaller roofs.
Gary Patrick, vice president for roofing consultant Inspec®, said DensDeck
Prime Roof Board was a natural choice for use in the extensive system.
“DensDeck functions as a great cover board for attachment of the waterproofing
membrane in The Target Center’s vegetative roof assembly,” he said. “It
provides a uniform substrate and can handle traffic very effectively. While
it’s not overly thick or heavy, DensDeck provides excellent support and
substrate. This is vital when you consider the vast number of people - and
products - that are moving over the system, especially during
construction.”
The Growth of Vegetative Roofs
Designed to be low maintenance, vegetative roof systems are becoming
increasingly popular as energy costs rise and environmental awareness increases.
In the 115,000-square-foot (10,684 m2) Target Center vegetative roof, 1/4-inch
(6.4 mm) DensDeck Prime Roof Board was installed over an Electronic Field
Vector Mapping grid, which was installed above three 2-inch (51 mm) layers of
insulation. A G476 Sika Sarnafil® PVC waterproofing membrane was installed over
the DensDeck Prime Roof Board. The waterproofing membrane is specially designed
to remain watertight in extreme conditions including constant dampness and
exposure to plant roots, fungi and bacterial organisms. DensDeck Prime Roof
Board was attached using Millennium Weather-Tite®, a low-rise foam
adhesive.
The use of Millennium Weather-Tite was the perfect choice because DensDeck
Prime Roof Board has an enhanced surface that provides a strong bond to the
insulation. “DensDeck provides a great protection layer in the system,” said
Rex Greenwald, environment solutions specialist for the project’s contractor,
Stock Roofing Company, a Tecta America Company. “A durable top layer is extremely
necessary and this was a great choice. In addition, the membrane system adheres
to it successfully and that’s an important criteria for
us.”
Extended Roof Life
The roofing project presented several challenges: the size and scope of the
project, the number of distinct disciplines integrated into the green roof, and
the addition of customized features. Of particular importance was protecting
the waterproofing membrane and insulation with coverboard.
“These systems see more roof traffic both during and after the assembly so you
need a proven layer of protection in the installation process and beyond,” said
Frank Anderson of Leo A Daly, architects for the project. “The coverboard not
only needs to provide extra protection from foot traffic, but from elements
such as hail, snow, wind and moisture.” The roof assembly beneath the vegetated
roof is expected to last up to 40 years, or nearly twice that of a conventional
roof and DensDeck Prime Roof Board is a key component in the assembly. For more
information, visitwww.densdeck.com.