Architects, including
RC3D, should incorporate sustainable design criteria into building specifications.
Choosing the correct wall system is part of good sustainable design. Today we are going to talk about green wall systems, their benefits and drawbacks.
There are two types of green walls: green façades and living walls.
Green walls are designed and engineered with a support structure, and can offer considerable cost savings to the homeowner. Green walls also reduce the urban heat island effect, and reduce energy consumption. Cities are cooler and quieter through shading, evaporative transpiration, and the absorption of sound by green walls.
Green façades are wall systems where climbing plants or cascading ground covers are trained to cover specially designed supporting structures. Plant materials can be rooted at the base of the structures, in intermediate planters, or on rooftops. Green façades can be attached to existing walls or built as freestanding structures.
Plant selection will impact the design of the supporting system. Denser, faster growing plants require a greater space between supports than less aggressive species, which allow for smaller intervals between supports.
Wall-mounted green façades can be flush with walls or set 3"-18" from the wall surface using mounting clips or "standoff" brackets. A waterproof membrane is not required. The depth of the trellis modules protects building surfaces by keeping plants from attaching directly to walls to prevent problems that could otherwise compromise a building's integrity.
Living walls (also called biowalls, "mur" vegetal, or vertical gardens) are composed of pre-vegetated panels (panels grown in greenhouses) or integrated fabric systems that are affixed to a structural wall or frame. Modular panels can be comprised of polypropylene plastic containers, geotextiles, irrigation, and growing medium and vegetation. This system can support a great diversity of plant species, including ground covers, ferns, low shrubs, perennial flowers, and edible plants. Living walls perform well in full sun, shade, and interior applications, and can be used in both tropical and temperate locations.
Due to the diversity and density of plant life, living walls require more intensive maintenance than green façades.
Installation of pre-grown panels requires a lead time of 6-12 months prior to delivery for plants to propagate and grow first as plugs and to fill in the panels. A waterproof membrane is required for installation on metal or wood frame structures. An automatic drip irrigation system is also required.
These are the main support structures types:
- Modular trellis systems-rigid lightweight panels are installed vertically as either wall-mounted or freestanding systems. They can be used on tall buildings in conjunction with intermediate planters or on rooftops. These planters may be required where the growth of climbing plants is physically restricted.
- Freestanding structures, such as green columns or canopy tree forms made of rigid panels, can be placed on either urban streets or rooftops where space is limited or weight is restricted. The panels can also be used in horizontal applications such as arbors or as shading devices over the upper level of a parking deck.
- Cable and rope wire systems consists of high-tensile steel cables, wire trellises, anchors, spacers, and supplementary equipment. Vertical and horizontal wires can be connected through cross clamps to form a flexible trellis system in various sizes and patterns. To cover large areas, stainless steel wire-rope nets can be supported on flexible or rigid frames.
Green walls contribute to several LEED credits when used in combination with other sustainable building elements. Green walls reduce the solar reflectance of a structure, thus reducing the urban heat island effect.
Green walls can be utilized as wastewater treatment media, and provide additional insulation and natural cooling. Properly designed green walls contribute to innovative wastewater or ventilation systems.
Green walls retain and slow down storm water runoff resulting in less erosion, and reduced heavy metals in our water ways. Green walls double the life expectancy of a roof membrane. Green walls add acoustical value. Green walls regulate a building's internal temperature. Green walls clean the air.
Green walls are aesthetically beautiful, sustainable, functional, and lower the energy costs of a building. They are costly and require some maintenance and upkeep, but are advantages more then make up for it.
Contact us to learn more about green walls and green building.
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