Green walls: Difference between revisions

Living Walls are defined as vegetation that grows directly onto a building's facade or vegetation that is grown on a separate structural system that can be freestanding or attached to the wall. They can also be called green walls, green facades, bio walls, and vertical vegetation. Green or living walls are an emerging technology that integrate vegetation into the built environment.

What are Living Walls?

• Living walls are vertically oriented gardens usually climbing a wall of a building or structure. Living walls have been used for centuries in Europe; whether this was an intentional use of living walls or a natural process of local fauna overtaking an available medium probably depended on your class and knowledge.Today Living walls are re-entering the spotlight as an environmentally friendly way to reduce energy costs and bring nature back in to the human landscape.

• Living walls are a relatively untapped art and architecture medium.Growing plants become a dynamic and evolving artwork that requires periodic upkeep.

• Living walls can be purely decorative, produce food or medicinal plants in small areas, provide energy savings through reduced heat absorption and even improve the quality of indoor air.

Why build living walls?

Benefits of living walls include

• Lowering energy consumption and greenhouse gas emissions
• Reduction of Urban Heat Island Effect (UHI)
• Increasing the thermal performance of buildings(lowering energy costs)
• Improvement of Indoor Air Quality (IAQ)
• Reduction of Noise Pollution
• Increasing urban biodiversity and urban food production
• Improvement of health and well-being.^[1]

Health benefits

According to the U.S. EPA, Indoor air quality can sometimes be much worse than the outdoor air quality of the most polluted cities. Constant exposure to poor air quality can cause asthma, irritation, and a myriad of other health problems. Poor indoor air quality is often due to poor ventilation and off gassing of Volatile Organic Compounds from carpets, paints, upholstery, insulation,and countless other common products. Remedies for poor air on a small scale is limited to opening windows and fans while large scale systems often use HVAC systems. Living walls can be used on any scale to improve the indoor air quality.

Living Walls provide health benefits on both the physical and psychological levels. The plants using co2 and circulating the air in the room remove VOC's from the ambient air. This reduces negative health impacts associated with VOC's and poor indoor air. On a psychological level, plants can provide a calming effect on a room as well as increase worker efficiency. Quantifying a psychological benefit from plants in a persons space is somewhat difficult. However, qualitative reports of general improvement in mood and calmness are common in measuring effects of plants on human psychology.

Living walls can improve air quality through the photosynthesizing; absorbing CO2 and emitting oxygen.

Energy savings

Exterior walls Reduces heat island effect- The suns energy that used to reflect and radiate heat off of buildings is now absorbed by the growing plants. Reduces indoor cooling needs and costs- Shading from the plants on an exterior wall can decrease the temperature inside the building. Lower temperatures indoors reduce the need for air conditioning.

Noise reduction

Living walls absorb sound waves reducing city noise.

Reduces Storm Water Runoff

Soil absorbs rain, reducing runoff.

Protects the Building

• Absorbs acid rain, keeping it off the building.
• Protects against ultra violet rays.
• Reduces temperature change, which reduced expansion and contraction of building materials.

Creates Habitat

Creates Habitat for microorganisms, insects, and birds.

Application/Uses

How do living walls improve indoor air quality?

Air quality is improved by a biological process called biofilration. Air can be forced past the plants and the soil medium containing microbes that actually removes VOC's, dust and dirt particles from the air. The pollutants from the air are absorbed into a liquid phases and consumed by the microbes. The microbes use the pollutants as an energy source and degraded them to carbon dioxide and water. The air is then pumped through the traditional HVAC system and is redistributed in to the building. An estimated 65% to 90% of VOC's have been removed using biofiltration.

How do Living Walls reduces cooling costs?

Shading from the plants on a sunlight wall reduces the amount of direct light hitting the structure. The energy absorbed by the plants is converted in to sugars through photosynthesis instead of reflecting and radiating most of the energy (heat) striking the wall.

Indoor living walls can also reduce cooling/heating costs. Traditional HVAC systems must, by code, replace a certain amount of indoor air with fresh outdoor air every hour. While this is being accomplished the outdoor air must be heated/cooled to the desired indoor temperature. With an indoor living wall system the same air is used over and over again. The air is filtered by the living wall and maintains its temperature, eliminating the need to heating and/or cool outdoor air.

Design

How are Living walls made?

Any plant requires a type of growing medium. Some plants require a lot of medium in order to flourish, other plants need very little. The first element to building a living wall is the physical structure of the wall. Plants need water and moist soil, two things not commonly found anywhere near drywall. Some method of retaining the drip from plants and soil is a good first step.

• build the medium, a rectangle with little cubbies at slight upward angles.
• For a home:
• For a large scale HVAC inter-tied system:

Types of Living Walls

Living walls to choose from:

• The panel system are a pre-planted system that you can buy from a company such as from panel specialists at ELT Living Wall Systems.^[2] Once purchased you can either install the panels yourself or have an expert install it for you onto an existing wall indoors or outdoors along with an irrigation system.
• In Felt Systems plants are fitted into felt pockets of growing medium and then attached to a waterproofed backing which is then connected to the building behind. An example of a felt system is Patrick Blanc’s Vertical Garden which is composed of a metal frame, a thin PVC sheet, and a felt polyamode layer which is attached to the PVC.
• Finally, Container/Trellis System consist of that are grown in containers which climb onto trellises. Irrigation drip lines are put in place to control the watering and feeding of the plants.^[1]

What is the scale of a living wall?

• Living walls can be adapted to almost any size

a photo gallery of living walls

• Examples of large scale

• Examples of small scale, household size

Maintenance

If you consider living walls before the buildings construction occurs you can greatly reduce maintenance costs. Once the initial panels are in place living walls require little maintenance. They are designed so that their upkeep is about the same as a landscaped garden. Most important to the upkeep of living walls are their irrigation systems. Living walls are basically hydroponic systems where water and nutrients are fed to the wall through some means of mechanical irrigation. Some living wall systems are designed to collect rain water and/or reuse gray water.^[1]

The panels sold by ELT are designed to allow the water to flow from cell to cell within the panel and from panel to panel within the wall. The water flows internally within the panels. The water flows from the top grooves in each panel, through the subsequent grooves, until it reaches to bottom of the panel where it drips out from the drainage channels and into the panel below. Irrigation systems are designed with automatic timers for ease of use.^[3]

Types of Plants to use

The plants you choose for your living wall vary greatly. Depending on the amount of sunlight available, the space available and also the different places on your living wall (and different exposure to water) and whether your living wall is indoors or outdoors. There are many choices to choose from. There are also many vegetables that have been grown successfully in living walls.^[4]

Concerns

• Moisture must be controlled to avoid mold growth.
• Plants will attract insects.
• Must be careful to choose plants that won't release excessive pollen.
• Plants must be maintained. Including, trimming, watering, replanting, and washing.

Notes

See also

• Living roofs

External links

• Green Roofs? How About Green Walls! - EcoGeek, Wednesday, 17 October 2007.

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