Similarities Between Green Walls, Green Roofs and the Research That

Keeps Them Moving Forward By

Michael Furbish of Furbish Company, LLCMark Woolbright of Greenwall Ventures, LLC

Your eye goes right to the Green Wall in this picture, doesn't it.

Could you imagine a solid concrete wall here instead?

Annuals and perennials mixed for great aesthetics.

A 54 foot tall slope hidden in there by vegetation!

Green walls are easy on the eyes.

Hardy natives offer various growth habits that obscure the lines of an improved area while restoring needed habitat.

The right plant in the right place can have awesome results that last.

Green Wall 101• What constitutes a “green wall”?• Our intended definition of a green wall.• History of green walls starting in Europe and why.• Why has St. Louis been one of the only green walls

markets in the United States?• Other green wall markets in the United States.• Green walls are a conceptually different way to

manage grade changes.• Effects of regionalized product availability and no

consistent message or information portal.• Benefits and applications of green walls are similar to

green roofs but in need of published data.

This is Hardscape and it is everywhere. Can Green Walls begin to overtake them as the mainstream , rather than the niche?

Conventional retaining wall vs. Vegetated retaining wall

Hardscape vs. Landscape

ConventionalRetaining Wall

VegetatedRetaining Wall

Aesthetically attractive alternative to hardscape

The “big” questions!

• Why do you want it green?• How do you get it green fast?• How do you keep it green?• Does it require maintenance and if

so, is it intensive?• Does it have benefits beyond just

holding back an embankment?

Solid concrete walls are not as easy on the eyes.

Why Choose A Green Retaining Wall Over A Traditional Retaining Wall

A green retaining wall minimizes the impact of a needed structure while increasing “green space” lost in development.

 A green wall reduces the “Heat Island” effect by moderating fluctuations in temperatures at and near the structure day and night.

 A green wall is another stormwater management tool as they help reduce surface water runoff and filter pollutants from the water and air around it.

 A green wall can be a key component in a sustainable development plan and signifies an awareness of the need to make a difference.

 A green wall is cool on the eyes, reduces glare and may increase worker productivity as it fosters a greater sense of well-being.

•Green walls minimize the Impact of large structures.

A water treatment plant

An air filtration plant

A storm water management tool

An energy conservation tool

A low impact development tool

A capital savings tool

A habitat

A worker productivity tool

A public relations tool

A sales tool

A noise reduction tool

A Green Wall Is:

Green Walls start out pretty boringAnd end up pretty exciting.

Just planted with hardy vines and junipers.

Same wall after 3 years of growth.

Just planted with Sedum like a green roof would utilize.

Same wall after 2 years of growth.

Project Notes:

ConstructionPhase

The completed Reinforced Soil Slopes were dusted with Topsoil and spray seeded with hearty native plant material.

Completedproject the next year.

Project Notes:

The vegetation will requireNO maintenance and servesto minimize the impact ofthese large cost effective structures.

Roadway Slope Disappears into Habitat

Before After

Thermal Performance of BiowallsB. Retzlaff1, D. Gerstenecker1, L. Richter1, and M. Woolbright2

Southern Illinois University Edwardsville1, Green Wall Ventures2

ABSTRACT

Eighteen circular (7-foot diameter) green walls (donated by Hercules Manufacturing of St. Louis) have been located on the SIUE campus. The project is designed to evaluate the plant growth and performance of five Sedum species and one unplanted wall on north, south, east, and west wall aspects. In addition, the temperature of the wall, growing medium, and plant surfaces have been monitored on the same north, south, east, and west wall aspects. One of the Sedum species (' Bertrum Anderson') did not survive the first year of the study and we have replaced this species with mixed Sedum plugs. Walls planted with Sedum spurium and Sedum phedimus have approximately 75% growth media coverage after one year. Further, plant surface temperatures are less than wall block surface temperatures while the growing medium (Ameren Bottom Ash) has the greatest surface temperature. North and east wall aspects have the lowest afternoon surface temperatures - more than 25 degrees F lower than west and south aspects. Our data indicates that living wall systems have the potential to reduce the urban heat flux and that species selection may impact the thermal benefit.

SIUE PROJECT MATERIALS AND METHODS

Green Wall Setup – 3 replicates of 6 Green Walls each planted with one of four Sedum species, one with no plants (the control wall), and one with mixed Sedum plug in a completely randomized design. (Fig. 1)Green Wall Species - Sedum immergrunchen, Sedum kamshaticum, Sedum phedimus, and Sedum spurium The mixed Sedum species wall included S. spurium, S. sexangulare, S. cauticola, S. kamshaticum, and S. album Green Wall Medium - Bottom Ash mixed with composted pinebark donated by Ameren UE (Retzlaff et al., 2008)Green Wall Blocks - Donated by Hercules Manufacturing of St. Louis (Retzlaff et al., 2008)Project monitoring – wall surface temperatures on the north, south, east, and west aspects were taken monthly for 8 months. We began in September of 2008 and concluded in April 2009. An infrared thermometer was used to collect temperatures at the same time each afternoon. A one way ANOVA for a completely randomized design was used to test for differences between treatments. A Tukey’s post-hoc test was then used to rank differences at an alpha level of 0.05 (Proc GLM, SAS version 9.1)

SIUE PROJECT CONCLUSIONS

Average green wall surface temperatures are not statistically different in October or April (Fig. 1, 2).The North aspect stayed significantly cooler than the South aspect in April and October (Fig. 4,6; Fig. 5,7).Planted biowalls have a lower growth medium temperature than unplanted walls in October 2008.

Green Wall Temperatures 04/03/09

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INTRODUCTION

Green (living) walls may be used to help cool cities and reduce the Urban Heat Island Effect. When the plants of a green wall grow to maximum coverage, their shade and evaporation should help to reduce the amount of heat that would have been absorbed by the wall material. Evaluation of the biowalls planted at SIUE is needed to determine which plant species provide the greatest thermal benefits. This study evaluated the surface temperatures of 4 different Sedum species walls, a mixed Sedum species wall, and a control wall with no plant species. Our hypothesis was that planted walls would have lower surface temperatures than unplanted walls.

DISCUSSION

Significantly different temperatures for the control walls and species planted walls are a desirable outcome for living wall systems. The plant and medium can act together as a thermal unit that provide a cooling layer to building material (Sidwell et al., 2008). The study of these thermal environments are to determine how great the benefits in temperature reduction are per plant species throughout changing atmospheric temperatures. This study helps to promote the idea that green walls can reduce the effects of the Urban heat Island caused by development. The coverage of a plant has a direct correlation with the temperature of the medium and block it is placed in. The greater the coverage of the species the lower the temperatures the medium and block should be. The dark surface of the medium heats up, but with maximum growth, the plant should provide shade and reduce the amount of heat absorbed. The coverage and maximum growth can influence the temperature, and help provide optimal thermal benefits (Koehler et al., 2006). The ability of the living wall to collect rainwater and the process of evaporation are also factors that may lead to cooling of the building material (Koehler et al.,2006). More studies are needed to determine how great an influence biowalls can have on the surrounding thermal environment.

Fig. 2 Fig. 3

Mean temperatures of the plants, medium, and blocks per species in the months of October, 2008 and April, 2009).

Fig. 4 Fig. 5Mean temperatures of the plant species, growth medium, and blocks per species from the South aspect for the months of October and April.

Fig. 6 Fig. 7Mean average temperatures of the plants, medium, and block per species from the North aspect fort he months of October and April. (Medium with different grouping letters are statistically different from one another)

Fig. 1

Green Wall Temperatures on South Aspect 10/30/08

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REFERENCES:Sidwell, A., Gibbs-Alley, J., Forrester, K., Jost, V., Luckett, K., Morgan, S., Yan, T., Noble, B., and Retzlaff, W.,2008. Evaluation of the thermal Benefits of Green Roof Systems.Koehler, Dr. Manfred, 2006. Living Wall Systems- A View Back and Some VisionsRetzlaff, W., J. Middleton, M. Woolbright, V. Jost, S. Morgan, and K. Luckett. 2008. Evaluating the performance of the Ecoworks living wall system. Proceedings Sixth Annual Greening Rooftops for Sustainable Communities Conference, Awards, and Trade Show (available www.greenroofs.org).,Baltimore, MD.

Green Wall Temperatures on North Aspect 10/30/08

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RESULTS

How about a simple, space efficient urban garden.

Unlike green roofs, the media is “in the face” and greatly “behind the face.” This fact presents the greatest challenge in design but the greatest benefits to site development and the environment once good laboratory data is published..

Site water runoff

Site water runoff for capture in slope backfill zone

18 test walls are being set up at the SIUe field site so Dr. Bill can start “killing” plants for our first trial series.

Before the plants are added to the study walls.

Dr. Retzlaff hard at work planting the walls.

The next season with growth and a view of one of the controls walls that was not planted.

Spring in Atlanta, GA. test trial wall.

Summer in the same wall! Trials like this make it easy to identify the species that give thermal cover.

Thank you for attending our presentation!