- System Description
- Campus Context
- Goals and Targets
- Lessons Learned
- Future Learning
Image 15.1 Living Roof & Living Wall Diagram
Illustrating the integration between natural systems and the built environment was of primary importance for CIRS. The living wall and living roof are part of the building’s visual display of ecologically integrated building systems, demonstrating the nature of the research institution, as well as performing a multitude of ecological services and practical building performance functions. Located above the MGD Auditorium, the living roof is visually and physically accessible to building inhabitants and visitors. It is planted with native plants designed to provide habitat for local animals and insects and is an important part of the water management strategy for the building. The living wall provides solar shading for the western façade that is both passive and dynamic, as the leaves of the vines change color throughout the year and fall in winter. It also enhances the public face of the building with distinct character that expresses the sustainability principles of the CIRS project.
The roof of the lecture hall is covered in a garden of native plants. The plants include a wide variety of ground cover, shrubs and woody materials, all native to the lower mainland. The low profile plants require a relatively shallow amount of growing medium (45 cm) and are hardy enough to withstand some variation in the amount of irrigation. Both deciduous and evergreen plants were included to create a diverse habitat for insects and birds. The green roof provides an interesting view for inhabitants of the upper office floors, whose windows face inward, across the building courtyard. The landscape is built on top of a membrane type roof structure specifically designed to accommodate it. The growing medium is held in place by an erosion net and L-shaped soil retainers, below which a corrugated drainage layer catches and channels excess water off the roof. The membrane is sandwiched between a protection mat and rigid protection board to protect it and the rigid insulation below from penetration by growing plant roots.
Roof Layers: (top to bottom)
- Soil Erosion Net
- Light Weight Growing Medium
- Soil Retainer
- Drainage Layer/water Reservoir
- Protection Mat
- Water Proof Membrane
- 13 Protection Board
- Rigid Insulation
- Vapour Barrier
- Laminated Wood Structure
The living roof is an integral component of the building’s water management strategies. The roof reduces stormwater runoff by absorbing and utilizing the rain falling on it as irrigation. The rainwater is supplemented by reclaimed water treated by the Solar Aquatic System (see Section 13.0 Reclaimed Water). The roof also indirectly reduces the burden on the municipal sewage treatment system; in the summer months when the building is sparsely occupied, the solar aquatic system imports sewage from the municipal system in order to maintain the volume of treated water available for irrigation in the driest months of the year. The need to provide steady year-round irrigation was one of the driving factors in this innovative “sewer mining” solution. The living roof is therefore supplied with nutrient and phosphorous rich water throughout the year, independent of both rainfall and the level of inhabitation in the building.
Image 15.3 Screen and Planters for the Living Wall. Photograph by Enrico Dagostini.
The living wall is a vegetated screen on the western façade of the building, facing West Mall. The western façade of any building is one of the most difficult to manage in terms of regulating heat gain and light. A living wall allows visual access for the public face of the building while still providing the necessary shading to create a comfortable indoor environment. Planters are mounted at each floor level, with a metal framework and mesh screen to create a scaffold for the vines. Chocolate Vines (Akebia quinata) were chosen for their suitability to the climate, vigorous climbing quality and ability to thrive in containers. These plants will grow thick foliage during the summer and drop the leaves in the fall, providing yearly variation in the amount of shade: more light will be allowed in during the colder, darker winter months and less during the warmer brighter summer months. Additionally, the leaves will change color over the course of the year, responding to the climate and the seasons, adding to the transformation of this dynamic façade.
Image 15.4 Living Wall Detail
Living Wall Components
- Green Screen
- Metal Framework
- Drip irrigation
- Galvanized metal grating
- Growing Medium
- Metal planter Box with metal steel supports and water proofing liner
15.4 Campus Context
UBC Campus Plan
The UBC Campus Plan emphasizes the natural setting of the campus and encourages the engagement of the community within it. The Plan also encourages high standards of sustainability performance for buildings, landscapes and infrastructure, by supporting innovation and experimentation through demonstrative living laboratory projects in new developments. Part of these efforts include a natural systems based approach to issues like water management, identifying waste streams as resources and using plantings native to the campus environment. The living walls and especially the living roof of the CIRS building are demonstrative examples of ways to meet these objectives, using plantings to provide both functional services and focal points of environmental engagement for the inhabitants and visitors to the building.
UBC Design Guidelines
The UBC Design Guidelines were developed to help coordinate the design of projects on the Point Grey campus, with the intention of accentuating UBC’s western coastal setting and improving the cohesiveness of the built and natural environments of the University. Projects are encouraged to integrate the design of new buildings and the surrounding landscapes as single compositions, and provide strong indoor-outdoor connections, both physically and visually, between the inhabitants’ interior working and social spaces and exterior environment. The green roof of the CIRS building, with native plantings and habitat, provides this connection. The Design Guideline emphasizes using passive design strategies to address lighting and heat gain in buildings, and encourages integration of such features into the overall design of the building. The guide prioritizes illustrative examples of natural cycles in the built environment to raise public consciousness of sustainable building practices. The living wall is an example of a passive design strategy (“passive intelligence”), creating a dynamic façade that responds naturally to the amount of shading required throughout the year, as well as beautifully highlighting natural cycles of plant growth.
UBC Technical Guidelines, Division 7
While the green roof provides many functions, including a key component of the wastewater system and a habitat, it is primarily a roof, and must perform as part of the building envelope. Division 7 of the UBC Technical Guidelines governs buildings envelopes, emphasizing thermal and moisture protection, including air barriers, insulation, cladding materials, types of roofs, fire stopping, sealants and accessories. Of particular relevance are sections 07200 Insulation Systems, 07500 Membrane Roofing, 07700 Roofing Accessories, 07840 Fire Stopping and 7900 Sealants. The design of the living roof must maintain these requirements, while incorporating the dirt, water and plants on top.
15.3 Goals & Targets
Table 15.1 lists the project goals and targets specifically related to the living roof and living wall. For a complete list of all the goals and targets for CIRS, refer to Section 4.0 Goals & Targets.
|3 - NET IMPACT||"Neutralize ecological impact on-site by having a net positive biomass and oxygen provided onsite. Regenerate ecosystems to attract local fauna (birds, bees, herons & butterflies). Eliminate on-site run-off."||"Existing site plant coverage was 44% grass and shrubs. The new site will have more plant coverage (100% of which must be native/adaptive species) than the existing site.Increase local native fauna on-site. 100 per cent stormwater will be treated, used or infiltrated onsite.|
|4 - POSITIVE COMMUNITY IMPACT||Maximize sustainable contributions to the local community.|
|6 - ENERGY REDUCTION||Design CIRS to be as passive and simple as possible. Design a high-performance building envelope.||Building envelope thermal performance to average R20(3.5 RSI)|
|10 - STORMWATER MANAGEMENT||"100 per cent stormwater will be treated, used or infiltrated on-site. Water leaving the site should be as good or better quality than when it arrived.Zero net runoff from site."||"Zero stormwater output from site. Clean all water used onsite, 100 per cent. Zero stormwater output from site.|
|16 - OXYGENATION||The building will oxygenate indoor and exterior environments.|
|17 - COMFORT & CONTROL||"Provide areas for social interactions, physical activities and human health needs."|
|22 - PUBLIC EDUCATION||"CIRS will disseminate sustainable design practice, knowledge and experience as widely as possible."|
Table 15.1 Goals and Targets for the Living Roof & Living Wall
The living roof and living wall of CIRS benefit the project in the following ways:
Utilizes Passive Building Intelligence
The plants’ natural cycle of foliage is complementary to the amount of daylight desired in the interior of the building. The plants provide shade during the summer and allow more light in during the winter. The living wall also creates a beautiful, dynamic façade without any energy input or human intervention.
The living wall is unique on the UBC Vancouver campus at this time. Both it and the living roof are literal illustrations of the sustainability principles of the CIRS project and provide points of visual interest and an ecological connection for people both inside and outside the building.
Provides Ecological Services
By using natural elements in building components, those components provide ecological services as well as the building functions. For example, the mix of native plantings on the living roof will create habitat for insects and animals, such as spiders, flies, ants and birds, and the water used for irrigation is returned to the atmosphere through natural evaporation and transpiration processes in the plants.
The living roof and living wall of CIRS were challenging for the project in the following ways:
Using Specialized Plantings
Plants that are used in conjunction with building components must be able to survive in different conditions than ground based plants. Plants in both the living roof and living wall must be able to thrive in situations that restrict their root growth and water intake, handle exposure to different amounts of sunlight and wind than at ground level, and grow in predictable and specific directions (a vertical climbing vine for the living wall and low horizontal groundcover for the living roof).
Providing Year-round Irrigation
The reclaimed water from the Solar Aquatic System that supplies for the irrigation for the living roof and wall is dependent on the level of inhabitation and the flow of wastewater from the building. During the summer, when there is the least amount of rainfall and the greatest need for irrigation, the number of inhabitants in the building decreases. An additional flow of wastewater was required to maintain the optimal input for both the reclaimed treatment system and the building’s irrigation needs.
Supporting the Structural Load
The amount of water in the growing medium of the living roof, as well as the duration of time the water stays in the saturated medium and the growth of the plants meant that the live load on the Auditorium roof varies significantly throughout the year. The structural system in the Auditorium had to be designed to support the changing live loads of the roof, which are significantly greater than a traditional roof.
15.7 Lessons Learned
The experience gained through the living roof and living wall for CIRS provided valuable lessons to apply to future projects. Some key lessons are:
Seek Solutions to Multiple Problems
The cost of construction can be reduced if a number of design problems can be solved with one passive design solution. The living wall provides a visible expression of the project’s sustainability mandate, while also solving a solar shading problem and presenting an interesting, dynamic façade that reflects the seasons of the year.
Utilize Specialized Plants
The plants used in building components such as a living roof or living wall must be carefully chosen, planted and cultivated able to handle the environmental conditions while providing the services required of that building component.
Consider Water Resources
For projects that will use reclaimed water for irrigation, the landscape elements must be designed with a careful consideration of the amount and availability pattern of the water. Buildings with large seasonal differences in building occupation may face difficulties providing all of the project irrigation needs from reclaimed water or supplemental sources may need to be found.
Design to Accommodate Variation
Unlike conventional building materials and components, living elements utilizing plants will change throughout the year. In particular, growing plants will provide increase shade and variation in the amount of water absorbed will significantly change the weight of the building component. The design of the rest of the building must accommodate or make us of the variations.
Additional lessons learned over the operational life of the building will be added at periodic intervals.