Their participation in the design process can help to ensure green roof installation. ft.) that have a waterproofing layer anchored with stone ballast. The ideal window for planting green roofs in Minnesota is from after last frost until four weeks before first frost. Green roofs shall achieve a peak-to-peak delay of "x" hours for rainfall runoff. Green roof products shall be fully compatible with the waterproofing system and shall be installed in a manner that does not negatively impact waterproofing assembly in any way. lusher vegetation and moister soils provide greater evapotranspiration; sustainable use of stormwater harvested from hard surfaces, where harvested water is available; aesthetics: plants look greener more of the time; and. The low voltage method is a survey technique that can be applied to green roof that are designed to enable this approach. T&G plywood and Link to this table. Drainage components typically include the following. One important item to design for is an increased structural load. Damage to a wall can arise from wind forces, plant load, cable tension, and human access. The following components are part of almost all green roofs. In most assemblies, a fabric is selected that will freely admit plant roots. Green Roof Infrastructure: Design and Installation 201. Designs green roof system components above roofing membrane. the green roof system and any needed structural reinforcement. Dead load on 18 Gage N-Deck is 85 psf and less than the126 psf allowed. My dead loads will be closer to 25 PSF for 2" of concrete if I used 150 lb/cu. sun and wind exposure, precipitation, proximity to and exposure associated with glass curtain walls); project goals: e.g. Roof Material Dead Load Table. A structural engineer’s advice is essential to ensure comprehensive design development, based on the building’s construction, condition and weight loading capacity. Worker safety anchoring systems may also be desired and/or required. Performance specifications typically include required physical and chemical properties of green roof components and the green roof system as a whole, as well as required performance goals. Exposure B. The dead load of a typical asphalt-shingled, wood-framed roof is about 15 pounds per square foot. (cubic feet) of water as determined according to ASTM E2397). The Triptych external green wall is designed for a dead load of 80kg/m2. §[C26-902.6] 27-561 Roof loads. A one-way concrete slab system with beams and girders was designed for a typical 30’-0” x 30’-0” bay with typical 24” x 24” columns. Consequently, Sedum-based extensive profiles may qualify as ‘fire breaks’ on otherwise intensive green roof projects. Once a roof is fully covered with vegetation, the vegetation typically protects soil from erosion. The weight of all landscaping materials shall be considered as dead load and shall be computed on the basis of saturation of the soil as determined in accordance with Section 3.1.4 of ASCE 7. The following table shows some of the pros and cons of some potential green roof vegetation installation techniques. Project budget will be crucial to inform project feasibility and design. For example: Provides electricity needed on the green roof for irrigation as well as anything else that required electricity on the roof. Maximum system dead load of ___psf (determined according to ASTM E 2397 – 05 and E 2399 – 05). Under the roof ballast or pavers, the assembly is typically the same as for the green roof. If winter aesthetics are of concern, be sure to include some species with winter interest. Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau e.V. For this reason there are few, if any, initial capital costs. per sq. Testing after all construction traffic on the roof is complete will detect whether or not any leaks developed between the time of the first leak detection test and the completion of all subsequent work on the roof. For a 16-foot rafter, this then results in a 352 lbs. This protection layer is a water-permeable, synthetic fiber material with good puncture resistance. Maintains the primary contractual relationship with both the prime design professional and general contractor. Cantor, S. L. 2008. Leak detection systems allow for pinpointing the exact location of leaks and can also detect small imperfections in the waterproofing. Getter et al. Examples range from geotechnical matting systems like Enkamat, to slope restraint systems, cable grids, and mechanically attached structural grids. Inadequate drainage can result, for example, in structural loading problems, major damage to the building, as well as problems with plant health. For an excellent AWC's Appendix A lists a variety of live and dead load combinations for floors, ceilings and rafters. Examples of performance goals are listed below. The primary reason for not providing design specifications is that each green roof is unique and needs to be designed considering the factors discussed in this article. Use span tables for progressively heavier loads until you find the limits of your floor. 1.2D + 1.0E + L + 0.2S When H loads are present, they shall have 6. Potential irrigation water sources include: While almost all green roofs will need water during the plant establishment period, extensive green roofs can be designed without permanent irrigation. Even with reinforcement, slopes should be limited. For retrofitting a green roof, wall or facade, it is important to establish early whether the installation will meet the existing structural capacity of the building, or whether this will be modified to support the installation. grants, review of shop drawings, and permits). Examples of optional green roof components are listed below. climate and microclimate (sun and wind exposure, precipitation, proximity to and reflection from glass curtain walls); type and condition of existing waterproofing, deck, and parapet if retrofit; building HVAC systems, including nature of intakes and exhausts onto the roof surface and presence of ondensate releases; potential impacts on vegetation; impact on potential building heating and cooling energy savings; water storage and supply (spigot and tap availability); opportunities for rainwater harvesting and storage; source of power if needed for irrigation or installation; elevations of existing or planned parapets, door thresholds, sills of curtain walls; building code and insurance requirements; and. Review of proposed design to ensure that it meets municipal requirements. Construction observation and administration. No potential phytotoxicity shall be introduced through any of the temporary or permanent green roof materials or installation methods. Snodgrass. If irrigation does not use harvested water, not irrigating will be advantageous to lower water use and costs. For example, Appendix A indicates that one type of clay tile roof system has a live load value of 20 psf and a dead load value of 15 psf. Individuals passing the accreditation program requirements is trained in the following areas and therefore has a comprehensive understanding of all aspects of green roofs. The second most common conservative assumption found in the industry is to assume that the green roof is a soil load rather than a dead load. It is often part of the drainage panel. The uniform design live load in unoccupied landscaped areas on roofs shall be 20 psf (0.958 kN/m 2). Once vegetation is mature, introducing water from as low as feasible in the growing medium typically also results in the most resilient plants, as it draws plant roots to grow deeper. The growing and drainage media for the intensive beds and planters was also provided by SkyGarden. Normal standard for floors - depends - deck floor - attic floor, primary living area - sleeping room - lots of choices. Drainage capacity must also account for vertical sheet flow from adjacent facades or tall parapets. They are the designer of a scheme or plan. See the section on Cost-benefit considerations for green roofs. Plants exposed to seasonal moisture variations may be more resilient. W.W.Norton, NY. The ANSI/SPRI VF-1 External Fire Design Standard for Vegetative Roofs provides guidance for minimizing the risk of fire on green roofs, including recommendations for location and width of vegetation free zones for fire safety. The University of Melbourne’s demonstration green roof is designed for use by visitors and staff. Landscape Architects are responsible for the design of the natural environment similar to the way architects are responsible for the design of a building or structure. per sq. When using waterproofing membranes that are root resistant, such as, for example, PVC, TPO and EPDM membranes, a separate root barrier may not be needed. Popular Pages Pole Framing Post Connection Post Embedment Post Frame Foundations Rafter Installation Pole Barn Roof Weights Roof Styles Truss Bracing Trusses. Kits for All Purpose Buildings. A cost estimator calculates how much the green roof will cost during construction and during a determined maintenance period. This initial project budget should be updated at strategic points during the design process. Hanover ® Roof Pavers work hand in hand with Green Roof assemblies to provide environmental benefits while creating aesthetically appealing rooftops and plaza gardens. Reference Wind Pressure at 20' = 16.4 psf (0.5) = 8.2 psf: Dead Load (north roof) 12.0 psf : Dead Load (south roof) 2.0 psf : Structure: Our frame sections were welded locally from 2x3 inch tubular steel and 2 inch angle steel. As a Green Roofs in Sustainable Landscape Design. Maximum system dead load of ___psf (determined according to ASTM E 2397 – 05 and E 2399 – 05). Remember, these loads are distributed uniformly over the entire surface of the roof. reduce fire risk associated with air intakes or proximity to flammable materials and equipment; provide access for roof maintenance related issues; provide enhanced flow path toward drains out scuppers for runoff sheeting off walls and parapets; and. 0.9D + 1.0E effect, or 0.9 when resisting the load when permanent. Photo by Andrew Wutke. Check when there is evidence of a leak that needs to be located. Reviews the distribution of material and equipment during construction. Green roof shall have a Rational runoff coefficient of "x", for storms with durations of X hours and return frequency of X years. The Importance of preserving an option for post-construction leak surveys will, however, influence the green roof design. When plants with vigorous roots are selected, an additional root barrier layer is often installed above root resistant membranes. controllers are available that time irrigation based on weather forecast and predicted evaporation rates, e.g. Therefore, a typical roof with 24-inch rafter spacing and rafters that weight 2 PLF would have a dead load of 10 x (24/12) + 2 = 22 PLF before the solar equipment was added. The frame was then sent off to be galvanized in the Boston area. I.e. Some projects will not need all these steps, some projects may need additional steps, and the order may need to be changed for some projects. Evaluates suitability of existing waterproofing for green roof. Wind or surface runoff erosion protection, Amenities: for example, walkways, gathering areas, site furniture, water features, lighting, interpretive materials, other structural elements such as trellises and arbors. Consult with a roofing consultant or other qualified professional to design the waterproofing assembly for a new roof, or to evaluate an existing roof on which the green roof will be installed. 1607.11.2.3 Green Roofs Where roofs utilize a green roof system and are not intended for human occupancy, the uniform design live load in the area covered by the green roof shall be 20 psf (0.958 kN/m 2). Designed by Gimmeblogs The extensive green roof assembly weighs 17 psf when fully saturated. Curbs or borders are also sometimes used to provide a firebreak or protection from wind uplift (Green Roofs for Healthy Cities and The Cardinal Group, 2006). Conducts energy modeling analysis to reduce HVAC requirements. A typical value for the roofing material itself is 10 PSF. Link to this table. - Gable • Raised Center Aisle / Monitor • … Examples include the following. Minimum system dead load of ___psf (pounds per square foot) (determined according to ASTM E 2397 – 05 and E 2399 – 05). Material Weight, psf Shingles: ... Dead load of roof of wood shingle construction = 10 lbs. Leak detection of green roof assemblies that incorporate root-barriers is very challenging, if not impossible in most instances. The surface of the vegetation free zones can consist, for example, of roof ballast or pavers. High voltage methods cannot be used in wet environments and therefore are useful only as constructon-phase quality control approach. Section 3.2. Water holding capacity affects how much water the growing medium can hold. Paper work associated with the green roof (e.g. General characteristics of extensive and intensive green roofs (adapted from Green Roofs for Healthy Cities and the Cardinal Group, 2006). For those designing the vegetated roof, the extra dead load of mineral fiber can increase costs for structural elements overall in the roof, the walls or columns supporting it, and the foundation. 2007; Van Woert et al., 2005). 2004. Unlike the low voltage method, however, these systems can provide real-time on-demand information about the waterproofing status and alarm owners if a problem is detected. Paper work associated with the green roof (grants, review of shop drawings, permits, etc). While not all extensive green roofs require permanent irrigation, almost all green roofs require irrigation during the establishment period (unless adequate rainfall occurs), often several times a day. Several types of leak detection systems are available, including high and low voltage surface surveys and built-in time-domain reflectometer (TDR) sensors. Other issues to consider are discussed in the section on construction sequencing. 2006. ANSI/SPRI RP-14 Wind Design Standard for Vegetative Roofing Systems provides guidance for minimizing risk of wind uplift on green roofs, including recommendations for location and width of vegetation free zones in areas of the roof particularly vulnerable to wind uplift and scour. Monitors construction compliance with plans and specifications. 0.9D + 1.0W a load factor of 1.6 when adding to load 7. An engineered slope stability analysis should be performed for green roofs with slopes above 2:12 (10 degrees). Other key elements of green roof specifications typically include, but are not limited to the following: This page was last edited on 13 April 2020, at 12:40. The University of Melbourne’s demonstration green roof is designed for use by visitors and staff. ft. portland cement with no gypsum or fillers (heaviest scenario I would envision). can be programmed to not irrigate for set length of time before rain is predicted. Water retention layers are available in a range of water holding capacities, typically between 0.06 gal/ft2 and 0.16 gal/ft2. Structural engineers use the solar panel roof load calculator to come up with the correct load capacity of the roof material. Determines the condition of the roof membrane and provides recommendations regarding roof repairs, in existing structures. Portions of the green roof above and below 6 inches, with a minimum of 25% of green roof area above or below 6 inches, Varies, but generally lower than for intensive green roofs, Varies, but generally higher than for extensive green roofs, More growing medium and more vigorous plant growth provides marginally greater stormwater volume benefits, Quick, 1-2 years depending on species, plug size, and initial planting density, Allows for most flexible and controlled planting design; can be added to green roofs started from cuttings or to pre-grown mats to increase species diversity, Small pieces of sedums that are spread across or mixed into growing medium, Less control over final look than with plugs, Longer than plugs or cuttings – typically 2-5 years depending on species, Less control over final look than with plugs; seed cannot be allowed to dry out until germinated; more bare soil can result in higher weed pressure; need more erosion protection during establishment since soil is bare; only a limited number of species can germinate from seed on a green roof, Plants delivered to the site pre-grown into an erosion control mat with growing medium, Instant erosion protection if fully vegetated; precise plant composition difficult to predict; less control over final look; less species diversity possible than with plugs, can be combined with plugs to increase species diversity, Plastic, metal, or degradable trays filled with growing medium and delivered to site pre-grown, Allow for greater precision of design, some may require frequent plant replacement due to edge effect; some trays may retain heat and cause soil to dry out faster, negatively affecting plant health. The values for dead loads in Table 3.2 are for commonly used materials and … Planting during extremely hot weather, above 90o F degrees or so, generally has long term negative impacts on plant health and should be avoided. ft. when used for storage only) Dead load of attic floor, not floored = 10 lbs. An independent roofing professional who provides information pertaining to the roof membrane, waterproofing, and determines what system would be best suited to the roof.