Real estate studies show that urban housing demands are on the rise. Members of the baby boomer generation looking to retire seek smaller residences that are easier to maintain and desire being in urban areas where they can readily access public transit, quality medical care and other lifestyle preferences. Members of the millennial generation want the convenience of living and working in urban areas that offers a wealth of amenities and a variety of transportation or walkable options.
Roof decks and terraces are now a must-have amenity space in urban environments and are easily added without increasing the building footprint by building-out underutilized roof space. Roof decks provide outdoor spaces that are easily accessible to residents and can be designed to accommodate social and recreational needs. New outdoor roofs incorporate a wide variety of site amenities including patios, dining and bar areas, putting greens, pools, garden spaces and grilling areas.
Business owners are also looking for office spaces that offer amenities as they help to increase usable office space, contribute to employee well-being by providing the opportunity for employees to get outside and walk or stretch, reinforcing the corporate brand identity of the integration of work and life, such as with large tech companies, all while creating a professional, creative and collaborative environment conducive to better business. Commercial building owners now understand the importance of shared amenities as an attraction for high quality office tenants, improving their tenant retention and increasing the overall building value.
There are a variety of products and materials that are utilized in the design and construction of roof gardens and decks. This article will review the basic types of roof systems as well as the range of hardscaping products that are available to designers.
The actual roof deck surface can be comprised of both hardscape materials and green planting areas. Roof deck areas can benefit the environment and human health and well-being by meeting certain Sustainable SITES and LEED criteria. In large part, they can help to reduce the effects from urban heat through the use of light-colored pavement surfaces and planting areas rather than the traditional roof surfaces of dark gravel and asphalt materials.
Some of the possible Sustainable SITES criteria that are applicable to roof deck systems include the following:
1. Site Context
a. 1.6 project located in existing developed area
b. 1.7 project connects to multi-modal transit networks
2. Site Design – Soils and Vegetation
a. 4.9 reduce urban heat island effect – with lighter colors on roof
3. Site Design – Materials Selection
a. 5.3 design for adaptability and disassembly
b. 5.5 use recycled content materials
c. 5.8 support transparency and safer chemistry
d. 5.9 support sustainability in materials manufacturing
e. 5.10 support sustainability in plant production
4. Site Design - Human Health and Well Being
a. 6.4 support mental restoration
b. 6.5 support physical activity
c. 6.6 support social connection
And the potential LEED criteria that are applicable to roof deck systems include:
1. Sustainable Sites
a 5.2 maximize open space
b 7.2 heat island effect
2. Energy and Optimization – optimize energy performance through reduction of energy demand
3. Material and Resources
a Recycled content
b Regional material
Housing & Community Design
Parks & Recreation
Urban Planning & Design
Health, Safety and Welfare
1. Identify the key sustainability criteria (LEED and SITES) for roof decking systems.
2. Discuss the considerations for evaluating the most appropriate materials for a roof deck project in terms of their structural performance and durability over time.
3. Explain the evolution of ballast systems to outdoor roof spaces.
4. Examine the available customization options for concrete tiles on roof decks.
Elena M. Pascarella, RLA, ASLA