Lightweight Expanded Slate Reduces Dead Load in Roof Garden: Gateway Village

Garden centerpiece. The gardens partially cover the underground parking facilities.

LOCATION Gateway Village Third Ward Charlotte, NC
PROJECT SPECIFICATIONS 15 Acre Mixed-Use, $450 Million Project. 65,000 sf Retail 583 Residential Units
DEVELOPER Bank of America Cousins Properties
CIVIL ENGINEERS ColeJenst & Stone
LANDSCAPE ARCHITECTS ColeJenst & Stone
LIGHTWEIGHT PRODUCER Carolina Stalite Company
LIGHTWEIGHT PRODUCT PermaTill, Expanded Slate
WATERPROOFING American Hydrotech
LANDSCAPING & IRRIGATION Southern Tree and Landscaping

GATEWAY GARDENS IS CENTERPIECE OF GATEWAY VILLAGE

Gateway Village is a mixed use development by Bank of America and Cousins Properties. It is located in Third Ward neighborhood of downtown Charlotte, NC. ColeJenest & Stone provided landscape architecture and civil engineering for development which offers office, retail, single and multi-family residential space and a centerpiece garden connecting the two main office buildings.

GATEWAY GARDENS COVER PARKING STRUCTURE

Gateway Gardens is a 1.5 acre park featuring a water garden containing fountains, a terrace with a cafe, and a central green area for outdoor concerts and events. The garden is located over a portion of the underground parking which serves both adjacent buildings. The portion over the parking deck needed special design considerations because it had to be waterproofed and the weight of all components had to be calculated and addressed. American Hydrotech provided waterproofing. Two thousand tons of lightweight fill and lightweight soil mixture were provided featuring an expanded slate lightweight soil amendment. The mixture specified had to be designed and prepared not to exceed the weight limitations for dead and live loading of the underground structure, while still providing good in-place compaction and drainage. The soil mixture also needed to securely anchor the plant material and provide for sustained plant growth.

TELESCOPING CONVEYOR USED TO PLACE SOIL MATERIAL

Putzmeister telescoping conveyor used to place lightweight
soil mixture over underground parking structure

The planters were filled using an ingenious piece of equipment called a Putzmeister Telebelt provided by Carolina Concrete Pumping. The Putzmeister is a telescoping conveyor system used to place material within a 60 foot radius. Southern Tree and Landscaping, a TruGreen Company, was the landscape contractor, and was responsible for soil placement, irrigation and planting.

A BRIGHT FUTURE FOR ROOFTOP GARDENS

Lightweight growing medium is easy to place and compact, and provides a secure anchor for plantings

Lightweight soil fills, especially in combination with structural lightweight concrete, is making rooftop gardens an attractive architectural alternative for designers around the world. In Europe, companies have developed and are marketing modular roof garden systems that employ Leca and crushed brick at a growing medium. In the U.S., you can contact a producer in your area who can provide the expertise, design criteria, products and installation of the latest roof garden and waterproofing technology.