How to WATER your GREEN building A catalogue for designing green building envelopes with integrated watering systems
Carlos Chang Lara Maaike Kok Joey Wagemans
How to WATER your GREEN building
24th of November, 2015 2nd edition Delft University of Technology AR0533 Innovation and Sustainability Designer’s Manual 4th quarter, 2013/2014 Tutors: Eric van den Ham Marc OttelÊ & Peter Teeuw
Students: Carlos Chang Lara 4330773 Maaike Kok 4092724 Joey Wagemans 4076354
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Table of contents 1. Introduction
6
2. Water
12
3. Vertical green
20
4. Horizontal green
34
Notes
42
Literature
47
Figures
50
1.1 1.2 1.3 1.4
What to expect? How to read? Symbols greening systems Symbols watering systems
2.1. How much water? 2.2 Water quality 2.3 Nutrients 2.4 Collection techniques 2.5 Irrigation techniques 3.1 3.2 3.3 3.4 3.4 3.5
Rooted into the ground Rooted into a wall Rooted into potting soil LWS based on planter boxes LWS panel systems LWS felt system
4.1 Extensive 4.2 Intensive 4.3 Closed system
6 7 8 10 12 14 15 16 18
22 24 26 28 30 32
36 38 40
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1. Introduction Are you building a green facade? Or maybe a green roof? If yes, then which type of green roof/faรงade do you choose? Your choice determines the amount of water which is needed for irrigation. Moreover your choice immediately narrows the amount of irrigation systems applicable. As each different system has specific watering conditions and varying retention capacities. This manual offers you an array of possibilities on how to water your greening systems. It inspires you and gives suggestion of how to capture water from nature. Thereby saving your client a lot of water consumption.
1.1 What to expect?
First some basic knowledge about irrigation is provided. Such as how do you calculate the amount of water that is needed for your greening system? What factors are important to maintain the water quality? And what are the most important nutrients that plants need? Secondly a catalogue of some innovative water/rainwater collection-, storage- and irrigation systems are presented. These systems function as an inspiration, which could be adjusted to your personal watering needs. Finally, different greening systems are presented. By which the manual guides you in the selection of a greening systems. For each greening system recommendations are given or watering techniques that are most suitable or interesting.
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1.2 How to read?
The general layout of the catalogue is explained below. This format starts from chapter 3 and ends at chapter 4. You can easily recognize the properties of each systems by flipping through the pages. On the left side the green system properties can be identified. The blue icons on the right side illustrate the watering systems.
Numbers refer to Notes on page 42 for more indepth information. Icon is opague, meaning that the item is not applicable to the discussed system.
1
Opaque
Bright
Of every icons there are three varieties unless stated otherwise. For example, water retention of the substrate:
Low
Medium
High
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1.3 Symbols greening systems Investment costs
The investment costs are illustrated with this symbol. The price does not include the plants, since the price per plant can vary. The soil is included in the price.
Realization time
The realization time is the average time it takes to cover an ordinary facade or roof completely with plants.
Weight
The weight is the total weight of the system without the plants, but with the soil. The weight of the plants themselves can vary per plant species. This depends thuse very much on the design made.
System width
These symbols explain the thickness of the system itself: the thickness of the structure and the substrate. Plants and air cavity are not included. To calculate the total system width, the width of the air cavity, if present, should be added to this system width. The upper icon is used in the vertical green chapter. The lower icon is applied in the roof section.
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System height
Plant growth can be negatively influenced by wind and dessiccation. It also depends on the types of plants species that are applicable for the system. Only applicable for vertical green.
Air cavity
This symbol shows the air cavity between the vertical greening system and the outer wall of the building. Only applicable for vertical green.
Plant variety
Some systems can only hold few plant species, others can accommodate a high variety of species. This icon shows the plant variety that is possible for the system. Only applicable for green roofs.
Modularity
This icon shows if the system is modular or not. In some systems, the plants can be moved around and rearranged easily. If this is the case, the icon is highlighted, if not than than the symbol is opaque. Only applicable for green roofs.
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1.4 Symbols watering systems Investment costs
The investment costs for the irrigation system are illustrated with this symbol. Note however that some systems are able to earn back money by not using energy.
Maintenance
This icons shows the estimated amount of effort needed to maintain the irrigation system.
Energy
Does an irrigation need additional electricity or not? If it does this icon is shown. Some systems provide themselves with power, which means they don’t need additional electricity, than the icon is opague.
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Location of irrigation
Is the irrigation system positioned in the subsurface or on top of the surface? This icon shows where the irrigation system is located: in the substrate layer or above it.
Substrate water retention
This icon shows the capacity of the substrate to retain water.
Irrigation network
Is the water provided by a central irrigation system or not? This icon reflects wether the irrigation system provides water to a single plant or is part of a network that delivers water to multiple plants.
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2. Water 2.1 How much water?
Calculating the amount of water of your system is the first step you should take before determining your watering method. The amount of water you will need is determined by the green system you have chosen, the plants selected and the location of your system.
Where is your building?
The location of your building will determines the range of suitable plants and their resulting water consumption. Also, the rate of water evaporation varies with respect to location; this water loss can be considerably high in hot and dry areas.
What greening system do you choose?
Whether you choose a vertical greening system or green roof, your decision determines the amount of irrigation needed. There are systems which barely need any irrigation and greening systems which cannot do without. Keep this in mind while designing your greening system.
Which plants do you want to select?
Once your system is chosen the suitable plants can be selected. The important parameters when selecting your plants are location, green building system and amount of water available.
Estimate the water consumption!
Estimating the water capacity needed for your system, helps you to determine the size of a water storage tank. Which sometimes might be necessary to guarantee an all year round water supply. An example of the steps is presented in the calculations on the right.
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1.
Find the amount of water needed
Equation
Agreen * rirrigation =
Vneeded
Example
Felt layer system: Agreen = 30 m2 rirrigation = 3 L/day/m2 30 [m2] * 3 [L/day/m2] =
2.
Find the amount of collected water
Equation
AAR * Acollection - e =
Example
Average annual rainfall in the Netherlands: AAR = 700 mm/year/m2 Acollection = 30 m2 e = 15% 700 [mm/year/m2] * 30 [m2] * (1-0.15) =
3.
Vrain
17,9 m3/day
48 L/day
Find the size of the water tank
Equation
Vneeded + Vsubstrate - Vrain =
Example
Felt system: Vsubstrate = 0 L/day 90 [L/day] + 0 [L/day] - 48 [L/day] =
Where: Agreen rirrigation Vneeded AAR Acollection
90 L/day
= Surface area of the greening system = Irrigation rate necessary for the greening system = Amount of water needed by the greening system = Average Annual Rainfall = Surface area of the rainwater collector
Where: e Vrain Vsubstrate Vtank
Vtank 42 L/day
= Evaporation = Amount of water collected from rainfall = Amount of water retained by the substrate = Volume of the water tank
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2.2. Water quality
The quality of the water is important when irrigating your green system. Usually this is checked by taking a water sample and analyzing the state of several factors. Some of these factors are shown bellow:
Suspended Soils The dimension of the particles in water can provide an idea of the filtering process and amount of matter needed to be removed.
pH Should range 6.5 – 8. The level of pH determines the type of chemical reaction taking place in the water Fe When present in a soluble form Fe usually causes clogging problems, even wat very low concentrations. Iron particles can dissolve due to a temperature and pressure difference, an increase of pH or as a response to the presence of bacteria. Sulfides At low concentrations, sulfide bacteria can emerge creating possible clogging. Bacteria Keep the bacterial population under 10,000/ml. Above this limit the water will have to be treated. Oil Can be naturally present or can be a product of the degradation of plastic elements from the irrigation system. Oil can collect sand grains and other solids creating clogging problems.
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2.3. Nutrients
The plant nutrients have the form of salts dissolved in the water. Plants incorporate these salts through their roots by means of the osmotic pressure. Salinity can be measure by its electrical conductivity (mmho/cm) or the number of total dissolved soils (ppm). Where 1 mmho/cm is equivalent to 640 ppm. The optimum amount of salts varies widely depending on the plant type. B Small concentrations are essential for plant growth. However the threshold is very small and slightly higher concentrations can be toxic for the plants.
Cl Found in most water samples. This can be toxic for some plant types.
Ca / Mg Ca / Mg rich soils are exhibit good workability. Water retention is higher. NO3 Nitrate is not so common in natural waters. It contributes to the growing of the plant however; it can have unwanted effects on plant maturation and ripening. High nitrates levels may mean the excess on the use of fertilizers or the contamination due to sewage. HCO3 Can be present as Sodium, potassium, calcium and magnesium bicarbonates.
ClNa+ Na / K These are very soluble salts. Na/K rich soils exhibit poor properties for growing plants. When wet, Na/K is nearly impervious to water, when dry it is very difficult to remove.
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2.4. Collection techniques Main System
The main system belongs to the main municipal water supply. The main benefit is that the storage tank is no longer necessary. However, the system depends on the municipality and in some areas irrigation might be restricted to certain times a day.
Spontaneous rain
By selecting the right plants and their location it is possible to have the irrigation completely based on the precipitations without any further maintenance (i.e. climber plants). This depends on the annual rate of precipitation among other parameters.
Controlled rain
By collecting and storing rain water you can create a locally sustainable green system (i.e: no need of main water pipes). Also it is important to consider the reduced of rain run-off during the rainy season.
Water leaves
Industrial designer Sabrina Goldin in Buenos Aires, Argentina has developed a rainwater-harvesting system that can be integrated in almost any infrastructure “Gota Verde” (green drop). It is based on a plastic “collecting leaf” connected to a polypropylene tube which distributes the water from the leaf to the storage1.
Partial roof harvesting
Finding available horizontal surface area for rain water collection is usually a challenge. By extending the parapets of a building (and thus increasing the collection area) a “partial” roof harvesting can be
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made. From the collection the gutters can redirect the water from the parapets to the storage.
Rain pod
This is a collector-storage of rain water with the same properties of a rain barrel. Designed by David L’Hote the system can be sized according to the watering needs. It is an elevated tank, which uses gravity to deliver low pressure irrigation to specific areas of the green system2.
Inverted umbrella
This innovative sytem is based on a garden with a central inverted umbrella that collects rainwater. It directs the water to an underground storage that irrigates the garden throughout the summer3.
Condensation based
When availability of rainwater is scarce, a solution might be to extract water from the air. Air has the capacity to hold water depending on the physical conditions of the environment.
Fog collector
This system is based on the condensation of water by means of a mesh. For mesh, the main considerations that have to be taken into account, are: the size of the filaments, the size of the holes between the filaments and the surface coating on the filaments.
Ground condensation
This system, designed by Equilicua, is a small-scale alternative for a domestic greenhouse. It does not fulfill the watering requirements, but it offers a great water saving technique. It is mainly based on the condensation of the water vapor that evaporates from the soil. It also protects the base of the plant and its roots. For this reason the system works very well with young plants.
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2.5. Irrigation techniques Deep soak method
This is the most water efficient irrigation method at this moment. It supplies water with at low pressure deep below the surface. This insures that minimum evaporation (i.e: evaporation rate almost 0%) takes place and most of the water is taken by the plants. You can save up to 50% of water in comparison to traditional watering methods.
Drip irrigation
This is one of the most water-efficient methods for irrigation. It is based on the low pressure water supply through a hose with small holes distributed alongside the irrigation area. Initial costs and intallation are the main constraints for this system. However, once properly set the low maintenance and high efficacy make up for the costs
Weeping line
This is also a deep soak method. Similarly to the drip irrigation method, it consists on a low pressure water supply through a hose placed deep alongside the irrigation area. The main difference is that the material of the hose is uniformly porous, making the water to regularly “sweat� out of the hose. This is a very water-efficient system, as well.
Surface watering
This is probably the most traditional irrigation technique. It is based on supplying water throughout the ground surface which means some evaporation will take place. It requires a lot of attention and might be time consuming.
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Watering can
Irrigation by watering can gives you more control over the plants that need watering. It delivers the water more gently than traditional hoses and some sprinklers. The main drawback is that the irrigation takes more time and effort.
Watering hose
The watering hose is one of the most ineffective irrigation systems. It can be equipped with a watering wand to decrease the amount of used water and increase the accuracy of the irrigation.
Sprinklers
The amount of effort is reduced with the automated sprinkler system. However they are one of the most wasteful systems. Sprinklers can be greatly optimized when automated, and different emitters might change the water consumption and the reach of the irrigated area.
Hybrid system
Airdrop irrigation
The Airdrop is a hybrid system because it combines a water collection technique together with a storage tank and an integrated irrigation method. The collection is based on air condensation powered by a turbine and the irrigation is based on a similar technique as the weeping line powered by a pump. The turbine and the pump are powered by a solar pv system. This is a fully integrated and sustainable system.
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3. Use in vertical green “Vertical green is the result of greening surfaces with plants, either rooted into the ground, in the wall material itself or in planter boxes attached to the wall in order to cover buildings with vegetation.�4 The picture below shows the classification according to literature for the different greening systems. As this manual focusses on irrigation. The different vertical greening systems are clustered according to their watering needs, one can see the index of this chapter in the picture on the right page.
Vertical greening systems Vertical greening systems Rooted into the ground Rooted into the ground Direct Direct
Rooted in artificial substrates and potting soil mixtures Rooted in artificial substrates and potting soil mixtures
Indirect Indirect
Direct Direct
Indirect Indirect
Green facades Green facades
1 1 2 2 3 3 4 4 5 5 6 6 7 7
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Living wall systems Living wall systems
1
2
3
4
5
6
7
8
9
10
11
12
13
1
2
3
4
5
6
7
8
9
10
11
12
13
Direct, Self climbers Direct, Self climbers Indirect, Self climbers
8
Indirect, climbers Indirect, Self Climbers that need a supporting system Indirect, Climbers that need a supporting system Direct, Self climbers
9 10 10 11
Direct, climbers Direct, Self Natural wall vegetation Direct, Natural wall Direct, Artificial wallvegetation vegetation
12 13
Indirect, Indirect, LWS LWS based based on on foam mineral wool Indirect, wool Indirect, LWS LWS based based on on mineral felt layers
13
Indirect, LWS based on felt layers
Direct, Artificial wall vegetation Indirect, Self climbers Indirect, Self climbers
8 9
11 12
Indirect, climbers that need a supporting system Indirect, climbers that a supporting system Indirect, Artificial wallneed vegetation Indirect, wall Indirect, Artificial LWS based onvegetation planter boxes Indirect, Indirect, LWS LWS based based on on planter foam boxes
Vertical greening systems Classification of the chapter Rooted into the ground
1
2
3
Rooted into a wall
5
6
9
p. 22
p. 24
LWS planter boxes
LWS panel systems
10
p. 28
11
12
p. 30
Rooted into potting soil
4
7
p. 26
8
LWS felt system
13
p. 32
21
1
3.1. Rooted into the ground
This type of green facades uses climbers, rooted in the soil at the base of the faรงade, to cover a faรงade. There are two systems:
2
- -
Direct, by which plants (areal roots and suckers) are growing straight against a wall; Indirect, where plants (areal roots, suckers, twining climbers, tendril- and scrambling climbers ) grow against a supporting structure positioned in front of a wall. Such as: timber battens, trellis work, steel cables or wire rope nets5.
Design tips 3
4
Plant the climbers by digging a pit for the roots and cover these with 30cm topping soil5.
Position plant min. 40cm from a facade5.
It is cost saving in comparison to wall stucco6, as the plants preserve the underlying wall against UV-radiation, moisture and temperature differences7.
A cavity between structure and climbers increases the effect of summer cooling and winter insulation5.
5
6
22
Check the wall conditions. Wall surface should not show any cracks or gaps. In addition the binding materials of the wall should be durable5.
Problems and risks
If the wall surface is in good condition, that is no caps, fractures or deteriorated binding materials, no damage will be caused to the wall7. However, plants can find their way inside a building by means of apertures (e.g. roof)5. Therefore plants need to be pruned every now and then. In addition the binding materials can deteriorate by the roots of the climbers. Thus, the binding materials should be restored if necessary. Also the supporting system can get detached from the wall5. Lastly, self-climbers can collapse by their own weight. To reach such heights the use of a supporting system is advised.
Airdrop
Designed by Edward Linacre, the airdrop system combines collection, storage and irrigation all in one. It is based on an air intake which allows humid air to condensate by the colder temperature of the soil. This water is stored in an underground tank and finally distributed by means of a semipermeable hose8.
The airdrop system uses an air turbine to ensure the necessary airflow, and a pump to distribute the water through the roots. These power-consuming parts are powered by means of a solar panel and a connected battery. This system produces all the energy it consumes8. The airdrop is also equipped with an LCD screen that helps monitoring the tank water levels., the pressure strength, the solar battery life and the system health9. Even though this system has been designed for farming purposes, it can be adapted for the rooted into the ground green wall system. This would be especially helpful in places where the avilability of water is limited, such as desert environments.
Figure 1. Airdrop system
Figure 2. With vertical green
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3.2. Rooted into a wall
There are two systems that root directly into a wall: Natural wall vegetation and Artificial wall vegetation. The difference between the eco systems is that for natural wall vegetation no human intervention is involved, while for artificial grown vegetation, plant growth is stimulated. 8
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Design tips
Use lime mortar or another fast disintegrating binding material, as plant growth flourishes by the disintegration of binding material10,11. Present day mortars are more durable and less suitable to facilitate plant growth.
Gaps and fractures facilitate plant growth11.
A slope makes it easier for sediments to settle11.
Tops and bases of walls are more likely to support plant growth, since those areas are more likely to have sediment deposition11. 10
Avoid thin walls (<30cm), especially free standing11.
Use binding materials with a low pH (6-8)7.
Problems and risks
Natural wall vegetation can cause damage to a faรงade. However, this is only applicable for higher plants that are only able to settle on a wall where cracks or gaps are already present11. It can take a very long time for them to appear (in average conditions more than 40 years11). The type of wall is important in the amount of damage: walls with binding materials with a low durability (e.g. lime) are more susceptible for deterioration. In concrete, cracks can develop further by higher plants, but natural wall vegetation will not easily grow on smooth concrete. The rule of thumb is; the less fractures or gaps, the less likely it is for high wall vegetation to be able to grow and thus cause damage.
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Rain
In the case of rooted into the wall systems, the substrate layer is often brittle and permeable and the irrigation is very limited. Moreover, in the case where a wall is the substrate layer, its structural integrity takes precendence before any irrigation or planting method.
Itâ&#x20AC;&#x2122;s for these reasons that the rooted into the wall systems usually have no designed irrigation. This system is quite spontaneous. They rely on precipitations, moisture levels in the air and the pH of the wall. In order to understand the optimum water conditions we use acrocarpous moss rooted into the wall as an example.
Acrocarpous mosses initial watering scheme
The first stages of the moss growth, after transplanting, are the most crucial. Therefore, hand watering is recommended during the first 5 months, after which the moss should grow fully independently12.
Tips
1st month 3rd month 4th month 5th month 2nd month
Best time to water is water every water once water twice water daily early in the morning, 3 days a week a month before dawn. High levels of chloramine or sulfur in the water can hinder the moss growth13.
Troubleshooting
If the moss is turning dark and there is a reduction in height then the moss is having too much water. The watering scheme should then be interrupted13. Figure 3. Acrocarpous moss
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11
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3.3. Rooted into potting soil
The vertical greening systems that are rooted in artificial substrates and potting soil mixtures need some kind of irrigation and the addition of nutrients, whereas rooted into the ground do not. This chapter is divided in green façades and Living Wall Systems (LWS). LWS are different from green façades as they can be developed into modular systems. Next to that the plants are not only rooted at the base of the wall, but rooted in a substrate distributed equally along the entire wall surface.
Green facades 13
Green facades can be applicated both direct as indirect. The difference is that the plants are rooted into pots at each floor level and not only at the base.
Design tips
14
5
It is cost saving in comparison to wall stucco6, as the plants preserve the underlying wall against UV-radiation, moisture and temperature differences7.
A cavity between structure and climbers increases the effect of summer cooling and winter insulation5.
Check the wall conditions. The wall surface should not show any cracks or gaps. Also, the binding materials present on the wall should be durable5.
Problems and risks
6
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Another problem might be that plants can find their way inside a building by means of apertures5, just like in the “Rooted into the Ground” system. Other problems and risks it shares with this system is the binding materials being able to deteriorate by the roots of the climbers. Therefore the binding materials should be checked regularly and if necessary be restored. A final problem that can occur is the detachment of the supporting system from the wall by the weight of the plants5.
Ground Condensation
Evaporation is the main problem of water loss any irrigation system has. In order to reduce such evaporation it is proposed to capture the water vapor from the ground. This is what the Econo domestic greenhouse does.
The Econo greenhouse is based on a plastic material made of polypropylene of 0.5 mm thickness. The idea is to collect water by means of ground water evaporation during the hot days and air condensation during the cool evenings14. Given the greenhouse effect this method offers, it provides a great opportunity to young plants (helps germination) and limits the risks of freezing. It also offers protection to the roots14.
Figure 4. Econo system
This system however is NOT water independent. It must be used as an addition to an existing irrigation technique. Nevertheless this system saves approximatelly 50% of the water consumed, depending in the local climate surrounding the system.
Econo Greenhouse system
Evaporation
Condensation
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15
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3.4. LWS planter boxes
This system is a modular system that contains planter boxes on the entire surface of the wall. Next to that Living Wall Systems are suitable for a wider range of species than green facades, therefore the function of the vegetated wall system can be addressed better10. This means the vegetated wall system can focus on e.g. air filterting, noise reducting, appeal by the choice of plants. Per square meter around 30 plants can be implemented10. The life expectancy of this system is over 50 years7.
Design tips 17
Can be used outdoors and indoors10.
If designing a wall with flowering plants, it is wise to combine them with evergreens in order to have an appealing vertical greening system all year round5.
Problems and risks 18
19
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A larger plant variety needs more attention, as for each specific plant the conditions have to be met. Plants can die (in winter) and have to be replaced10. This can affect the appearance of the green faรงade and replacement is difficult.
Fog Collector
The technology behind the fog collector is based on the condensation of water vapor in the air. This is trickled by the temperature difference between the collector and the air temperature. If the fog collectorâ&#x20AC;&#x2122;s temperature is bellow the dew temperature then condensation will occur.
Todayâ&#x20AC;&#x2122;s fog collectors are made out of a polypropylene or polyethilene mesh. The size of the voids are designed in such a way that once the water is condensed and trapped, the water droplets reach a certain size and drip15. Inspired by the Stenocara beetleâ&#x20AC;&#x2122;s capacity to collect water from air, the system is based on a combination of hydrophilic and hydrophobic materials that allow water collection and directs the dripping paths and modes15. When the planter boxes are part of a modular system, irrigation is usually more difficult. For this reason automated irrigation such as an automated drip line irrigation system is recommended.
Figure 5. Fog collectors Proposed arrangement for the fog collector in LWS - Planter boxes Fog Collector Planter boxes
Water Tank Main water supply
Figure 6. With planter boxes
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20
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3.5. LWS panel systems
This Living Wall System is based on panels of mineral wool and foam. The panels are usually already grown with plants. This makes them easy to install and creates an effect directly. The foam offers a pH neutral growing substrate and is therefore suitable for a wide range of plants10. As an example for panel systems, Fytowall (foam based) and Wallflore (mineral wool based) are discussed here. The Fytowall can accommodate 22-25 plants per square meter, the Wallflore can house 27 per square meter10.
Design tips 21
Can be used outdoors and indoors10.
If designing a wall with flowering plants, it is wise to combine them with evergreens in order to have an appealing vertical greening system all year round5.
Problems and risks 22
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The same problems appear as with LWS planter boxes.The larger variation of plant requires more attention due to the specific conditions that have to be met for certain plants. Also, replacement of dead plants is needed and might be difficult.
Most Living Wall Systems use the drip irrigation technique. This is because a great surface area can be covered and maintenance costs are reduced considerably. The low pressure flow allows for the irrigation tubes to be smaller.
Drip Line Drip irrigation works on a daily base with an operating pressure of 4 - 6o psi. The system has a great irrigation uniformity and energy savings potential16. This system usually have the irrigation elements integrated in the structure. It can can be controlled by digital sensoring. This consists of monitoring the water pressure at different stages of the system and responding to such demands through a microcontroller. Automated commercial drip irrigation systems offer reliable results, but initial costs are higher16.
Vegetation Layer
Figure 7. Drip line
Irrigation System
Structure
Typical drip line system scheme Usually the nutrient injection is performed directly in the water tank.
Water Source
This can be a low pressure filter. The filter reduces the chances of clogging.
Filter
Pump
The pump is the most energy intensive element. Optimizing this will greatly contribute to the energy savings.
Green wall
Control System and Check Valve
Figure 8. System scheme
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24
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3.6. LWS felt systems
The Felt layer system is built out of different layer of fabrics. In the felt pockets are made to insert the plants with some soil. Twentyfive plants per m2 can be housed by the felt system10. In comparison to other systems the life expectancy is, with 10 years, relatively short7. The system also needs continuous watering of about 3 litres water per m2 per day, in order to keep the felt wet10.
Design tips
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Can be used outdoors and indoors10.
Use only plants with short roots. The pockets have limited growth space10.
Lithophytes and epiphytes are plants which are best suited for the system17.
If designing a wall with flowering plants, it is wise to combine them with evergreens in order to have an appealing vertical greening system all year round7.
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Problems and risks
Pockets can get torn and the substrate might degrade, if so panels have to be replaced10. Furthermore, this system shares the same problems and risks as the other LWS systems, meaning more attention to the plants is required when the plant variation is higher and dead plants should be replaced.
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Weeping Line
The weeping line is basically an alternative to the drip irrigation system. The main difference is that while the drip irrigation system uses an emiter, the weeping line relies on the semi-permeable material of the hose. This way the water is distributed all along the hose.
It is already a widely used system for garden irrigation and has proved to deliver a good uniform irrigation pattern and contributes to the energy and water savings. The hose material of a typical flat soaker hose is nylon-coated PVC mesh (see image 10)18. Most of the regular soaker hoses are up to 70% made of recycled rubber and up to 30% of recycled polyethylene products19. Most living wall systems already available in the market use some form of drip irrigation. The Fytowall and the Wallflore systems are examples of irrigation integrated LWS. The amount and frequency of the irrigation is crucial for the success of the system. Weeping lines can be intalled within the felt pockets to allow the system to be fully integral. Weeping line Felt pocket
Tip: During winter, the irrigation system has to be dried in order to avoid the damage of the pipes from freezing.
Figure 9. Weeping line
Figure 10. Weeping line
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4. Use in green roofs This chapter will briefly explain the structural built up of a green roof in layers.
1. Plants, vegetation layer
This is the top layer, which consists of the actual vegetation.
2. Substrate layer
Next is the substrate layer which holds the soil. The thickness of the soil is dependent for what plants should appear on the green roof. It is important that the soil holds all the ingredients for plants; water, air and minerals. If plants are not fully grown yet, one can cover this layer with an erosion layer to prevent the soil from eroding.
3. Filter layer
This layer prevent small particles from the substrate to pass through to the drainage layer. This could clog the drainage system.
4. Drainage layer and water retention layer
This layer is used to buffer water and to drain surplus water. The drainage layer is a sloped layer with suitable pore voids so it moves excess water to the gutters or roof drains. The water retention layers is an optional layer and consists of sheets with cups or recesses on their surface that can hold water. This water can be used by the plants again in more dry periods.
5. Protection layer
The protection layer ensures that the roots of the plants arenâ&#x20AC;&#x2122;t able to work their way to the insulation, because this layer shouldnâ&#x20AC;&#x2122;t be penetrated by the roots.
6. The roof deck
This part of the roof is what can be found in most regular roofs. There is the structural part of the roof, mostly made from concrete or steel plates. This is covered by either the insulation or the waterproofing layer, sometimes with an addition damp-proof membrane beneath the insulation.
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1
2 3 4
5
6
Figure 11. Green roof layers
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4.1. Extensive green roofs
Green roofs can be divided into extensive and intensive green roofs. Extensive roofs are cheap, light and need almost no maintenance. Intensive roofs are expensive, heavy and need a lot of maintenance, but allow for more and bigger plants. One shouldnâ&#x20AC;&#x2122;t see this is a black and white division, but more as two ends of a spectrum. It is possible to build a semi-intensive green roof20,21,22,23.
Design tips
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Plants for extensive green roofs include sedums and other succulents, flowering herbs and various types of grasses and mosses.
Smaller plants require less soil which means less weight. This is why extensive green roofs are commonly used for existing roofs20.
Extensive green roofs are also ideal for sloped roofs, since it has small plants that are strongly rooted.
The plant material can easily be applied by placing pre- vegated mats or blankets, which can be done really fast.
Problems and risks
On roofs steeper than 12 degrees supplemental measures will be required to prevent sliding instability. One should also keep in mind that in the case of a leak a whole pre-vegateted mat should be removed to reach the leak.
Figure 12. Extensive green roof
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Capillary Layer The capillary layer works very simple. When it rains, the substrate will store the rainwater (up to 3 liters/m² per 10 mm depth of substrate24. Once the substrate is saturated, the excess water sinks to the capillary layer, which permits excess water to move to the outlets.
Extensive green roofs usually donâ&#x20AC;&#x2122;t need a permanent irrigation system, since they make optimal use of the capillary layer or drainage layer. Most systems can work purely on rainwater and are ideal for low maintenance stormwater management. The bigger your plants, the more need for a regulated irrigation system.
Figure 13. Rainy situation
On sunny days, the substrate dries out due to evaporation and plant usage. The water stored in the capillary layer diffuses back up into the substrate for the plants to use.
Figure 14. Sunny situation
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4.2. Intensive green roofs
The counterpart of the extensive green roof is the intensive green roof. A green roof being more intensive means itâ&#x20AC;&#x2122;s more expensive, it has more weight and it needs more maintenance than an extensive green roof20,21,22,23.
Design tips
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The big advantage of an intensive green roof is the fact that it offers a bigger variety of plants. In extreme cases, intensive green roofs can also hold bushes and trees20.
Trees can offer shade for the building, which helps for cooler buildings in warm climates. The biodiversity also increases25.
Intensive green roofs can also give the opportunity for small ponds, pergolas and playing grounds.
Problems and risks
Intensive green roofs need a thick layer of soil of more than 180 mm, which means the structure should be calculated for more weight. When placing trees, it should be noted that these should be connected to the structure. Otherwise the trees might tip due to the wind load. The structure should be calculated for this extra bending moment caused by the wind.
Figure 15. Intensive green roof
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Intensive green roofs offer a great opportunity to use the rain pod system due to its thicker substrate layer and the availability of vertical space to place a rain collector.
Rain Pod As the water level inside of the rain pod decreases, so does the irrigation pressure. This may become a problem whenever the pressure falls bellow 10 psi26. A rainwater collector does NOT have to look like a bargage bin. The rain pods can come in different sizes. They can fold in case of wind or snow.
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Figure 16. Rain pods
Tip: The gravity feed drip irrigation works best when the water pressure is 15 to 30 psi26. Rain Pod
Vegetation Layer
Rain Pod
Valve
Substrate Roof Structure
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4.3. Closed system
The closed system offers a container for plants or a single tree to be placed in. It can be simply nothing more than a set of plant boxes. The main advantage of this system is that the containers can be moved around. When the roof has a leak somewhere beneath a container, one can simply move the container to reach the leak. One can also easily change the arrangement of plant boxes when a new design is needed27.
Design tips
The closed system offers a bigger variety of plants. In extreme cases, planter boxes can also hold bushes and trees.
The containers are often made out of concrete, stainless steel or copper. Almost every material can be used, but one should consider the durability of the material, since it will be left on a rooftop where it could suffer from rain, hail, snow and high winds. The material should also not be poisonous to plants, so containers made from lead cannot be used.
Problems and risks
It might however be a good idea to connect the containers to the structure. When a container would hold a tree, it might tip over due to high winds. When designing a green roof with closed systems itâ&#x20AC;&#x2122;s important to take this into account, but make sure the containers are still able to be moved around (for example by connecting the container to the structure using simple bolts), otherwise you lose the main benefit of using this system.
Figure 17. Closed system
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Green roof systems offer a great opportunity to integrate a rain water collection system with the planting technique. Pots could use a large surface area, so they won’t tip over. This same area could be used for rainwater collection.
Closed collector
Figure 18. Collecting rainwater with a closed system The main advantage of the system seen in the above image isn’t only that the potted tree doesn’t have to be watered. The tree is also not able to tip without being connected to the construction. This means it can easily be moved around. When creating a system like this it is however important that there’s also a drainage pipe so excess water can find it’s way out.
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Notes 1
Investment costs: Direct system, rooted into the ground = € 0,- per m2 Indirect system, rooted into the ground7 ≈ € 10-30,- per m2
2
Realization time: More than 30 years; depends on the plant type used10.
3
Weight: Direct system, rooted into the ground = 0 kg/m2 Indirect system, rooted into the ground7 ≈ 1,6 kg/m2 Weight of indirect system is an estimation of a stainless steel mesh, it might differ a little for other type of meshes/battens.
4
System width: Direct system, rooted into the ground = 0 mm Indirect system, rooted into the ground7 ≈ 5-10 mm
5
System height is max. 30 meter5,7.
6
Air cavity: For an indirect system an air cavity between 40-60 mm is ideal7. No air cavity is included in the design of a direct system, however an air layer will emerge between the climber and the wall.
7
Investment costs: Natural wall vegetation Artificial wall vegetation
= € 0,- per m2 ≈ € 100,- per m2
Costs for artificial wall vegetation is based on prices of Growcrete (Betonindustrie de Veluwe b.v.), data retrieved from Marc Ottelé, 2014. The price might differ for other artificial systems.
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8
Realization time: The time span for higher plants to appear is much longer for natural vegetated walls than for artificial vegetated walls. For natural vegetated walls, higher plant growth can take between 40-80 years11. Thereby no wall maintenance and/ or cleaning should be undertaken11. The ideal wall age for natural wall vegetation to flourish lies between 100-500 years. Walls older than 500 years show decrease in biodiversity, due domination of a few species11. For artificial wall vegetation on the other hand it takes only 1-2 years for higher plants to grow7.
9
Weight: Natural wall vegetation Artificial wall vegetation
= 0 kg/m2 ≈ 70 kg/m2
Weight for artificial wall vegetation is based on Growcrete panels (Betonindustrie de Veluwe b.v.), data retrieved from Marc Ottelé, 2014. The weight might differ for other artificial wall vegetation systems. 10
System width: Natural wall vegetation Artificial wall vegetation7
= 0 mm ≈ 160 mm
With for artificial wall vegetation is based on Growcrete panels (Betonindustrie de Veluwe b.v.). Which exist of a 80 mm thick porous layer and a 80 mm thick structural layer. The width might differ for other artificial systems. 11
Investment costs: Direct system, rooted into potting soil7 ≈ € 15-35,- per m2 Indirect system, rooted into potting soil7 ≈ € 25-65,- per m2 This does not include plant costs of circa €10,- to 15,- per m2 (plant costs retrieved from Marc, Ottelé, 2014).
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12
Realization time: 2-3 years; depends on the plant type used10. Realization time is much shorter than for plants rooted into the ground, since it is assumed that plants are placed on each floor level. This is needed as plants in artificial ground have a limited growth (both height and width) due to the little root space available10.
13
Weight: Direct system, rooted into potting soil7 ≈ 7,4 kg/m2 Indirect system, rooted into potting soil7 ≈ 9 kg/m2 Weight includes HDPE planter box and potting soil, based on LWS planter box system. The LWS weights circa 88,8 kg/m2. Assuming 12 planter boxes per floor, result in 7,4 kg/m2 for one planter box per floor. Weight of indirect system is an estimation of a stainless steel mesh, it might differ a little for other type of meshes/battens.
14
System width: Direct system, rooted into potting soil ≈ 400 mm Indirect system, rooted into potting soil ≈ 400 mm Based on a planter box of 400 mm, needed to supply enough space for the climber roots. This size can differ off course depending on the plant type used.
15
Investment costs: LWS planter boxes7
≈ € 300 - 575,- per m2
This does not include plant costs of circa €25,- to 100,- per m2 (plant costs retrieved from Marc, Ottelé, 2014). 16
Realization time: Less than 1 year; depending on the plant type used10.
17
Weight: LWS planter boxes10 Depending on soil mixture used.
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≈ 25-40 kg/m2
18
System width: LWS planter boxes10
19
Air cavity: Most common for such a system is an air cavity between 40-50 mm7,10. Often the air layer is not ventilated for optimum insulation. Ideally an air cavity between 40-60 mm is wanted7.
20
Investment costs: LWS panel system, foam based7
= 200 mm
≈ € 650 - 1175,- per m2
This does not include plant costs of circa €25,- to 100,- per m2 (plant costs retrieved from Marc, Ottelé, 2014). 21
Weight: LWS panel system, foam based10 ≈ 88 kg/m2 LWS panel system, mineral wool based ≈ 15-50 kg/m2 Weight for the LWS foam panels are based on the Fytowall. Weight for the LWS mineral wool panels are based on the Wallflore system. The weight might off course differ for other LWS panel systems
22
System width: LWS panel system, foam based10 ≈ 140 mm LWS panel system, mineral wool based ≈ 80-125 mm Width for the LWS foam panels are based on the Fytowall. Width for the LWS mineral wool panels are based on the Wallflore system.
23
Air cavity: LWS panel system, foam based10 ≈ 50 mm LWS panel system, mineral wool based ≈ 45 mm Air cavity for the LWS foam panels are based on the Fytowall. Air cavity for the LWS mineral wool panels are based on the Wallflore system. Often the air layer is not ventilated for optimum insulation. Ideally an air cavity between 40-60 mm is wanted7.
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24
Investment costs: LWS felt system7
≈ € 250 - 725,- per m2
This does not include plant costs of circa €25,- to 100,- per m2 (plant costs retrieved from Marc, Ottelé, 2014). 25
Weight: LWS felt system10
≈ 90 kg/m2
26
System width: LWS felt system7 ≈ 20 mm
27
Air cavity: LWS felt system10 ≈ 50 mm Often the air layer is not ventilated for optimum insulation. Ideally an air cavity between 40-60 mm is wanted7. Weight: Extensive green roofs20
≈ 75-120 kg/m²
System thickness: Extensive green roofs20
≈ 75-130 mm
Weight: Intensive green roofs20
≈ 200-400 kg/m²
31
System thickness: Intensive green roofs20
≈ 180-600 mm
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Location of the irrigation: Even though the rain pod is placed above ground, all the pipes are placed below ground.
28
29
30
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Literature 1. Goldin, S. (2012). ‘Recolector de Lluvia “Gota Verde” / Eco-Logico’ Ch. 5, Canal de la Ciudad, Youtube Video, on website: https://www.youtube.com/watch?v=NaplncBBJWg. Consulted 23th of June, 2014. 2. Hartsfield, J. (2008). Rain Pod: Interesting...but is it usefull? http://www.greenfab-media.com/living-green/122/rain-podinterestingbut-is-it-useful. Consulted 24th of June, 2014. 3. Green Cube (2006). Chelsea Flower Show: Anna’s Sanctuary in the Shade. http://www.greencubelandscapes.co.uk/portfolio/ portfoliochelsea06.html. Consulted 24th of June, 2014. 4. Ottelé, M. (2011). The Green Building Envelope: Vertical Greening: TU Delft, p. 16. 5. Johnston, J., & Newton, J. (1993). Building green: A guide to using plants on roofs, walls and pavements. London: Ecology Unit. 6. Köhler, M. (2008). Green facades—a view back and some visions. Urban Ecosystems, 11(4), 423-436. doi: 10.1007/s11252-0080063-x. 7. Ottelé, M. (2011). The Green Building Envelope: Vertical Greening: TU Delft. 8. Varias, L. (2011). AirDrop Irrigation System Makes Water Appear out of Thin Air, Charges Nothing for the trick. http:// technabob.com/blog/2011/11/09/airdrop-irrigation-system/. Consulted 24th of June, 2014. 9. Prettejohn, S. (2011). Edward Linacre Airdrop Irrigation Australia. http://www.ecocitizenaustralia.com.au/edward-linacreairdrop-irrigation-australia/. Consulted 24th of June, 2014.
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10. Mir, M. A. (2011). Green facades and building structures. (Master thesis), Delft University of Technology, Delft. 11. Francis, R. A. (2011). Wall ecology: A frontier for urban biodiversity and ecological engineering. Progress in Physical Geography, 35(1), 43-63. doi: 10.1177/0309133310385166 12. Hill, C. (2011). Capillary Thread-Moss Bryum Capillare. http://wildedinburgh.tumblr.com/post/4062512002/capillarythread-moss-bryum-capillare-calton. Consulted 24th of June, 2014. 13. Moss & Stone Gardens (2014). How-To Grow Moss: Watering Mosses. http://www.mossandstonegardens.com/blog/how-togrow-moss/. Consulted 24th of June, 2014. 14. Econo (2008). What is it? http://www.equilicua.com/media/ ftp/equilicua-econo-booklet_en.pdf. Consulted 24th of June, 2014. 15. Cho, R. (2011). The Fog Collectors: Harvesting Water From Thin Air. Consulted 24th of June, 2014. 16. Bisconer, I. (2011). Toro Micro-Irrigation Ownerâ&#x20AC;&#x2122;s Manual (2nd ed.).Introduction. (pp. 4, 10) California, CA: El Cajon. 17. Baerends, L., & Boschman, B. (2014). How to design green highrises; Designers manual for vegetation on highrise facades in the Netherlands. Delft University of Technology. Delft. 18. Gardenerâ&#x20AC;&#x2122;s Supply Company (2014). Flat Soaker Hose. http:// demandware.edgesuite.net/sits_pod10/dw/image/v2/AABF_ PRD/on/demandware.static/Sites-Gardeners-Site/Sites-GSC_ Products/default/v1403523582081/Products/37-904.jpg?sw=840. Consulted 24th of June, 2014. .
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19. PRWEB (2014). Mr. Drip is offering three, 100ft Soaker Hoses to celebrate Earth Day 2013. http://www.prweb.com/ releases/2013/4/prweb10597338.htm. Consulted 24th of June, 2014 20. Breuning, J. (2014). Green Roof Types. Modern Green Roof Technology. http://www.greenrooftechnology.com/green-rooftypes/. Consulted 16th of March, 2014 21. Plant Connection Inc. (2014). Green Roofs: Extensive vs. Intensive. http://myplantconnection.com/green-roofs-vs.php Consulted 16th of March, 2014 22. Green Roof Plan. (2012). Intensive vs Extensive Green Roofs: Whatâ&#x20AC;&#x2122;s the difference? Consulted 16th of March, 2014. 23. Zimmerman, G. (2008). Extensive Or Intensive? Green Roofs Explained. Green roofs 101. Consulted 16th of March, 2014. 24. Alumasc Exterior Building Products LTD. (2007). ZinCo Green Roof Systems. In Alumasc Exterior Building Products LTD (Ed.). St Helens, United Kingdom. Consulted 20th of June, 2014. 25. Akbari, H. (2002). Shade trees reduce building energy use and CO2 emissions from power plants. Environmental pollution, 116, S119-S126. Consulted 16th of March, 2014. 26. Drip Irrigation (2008). Gravity Feed Drip Irrigation. http:// www.dripirrigation.ca/HowTo_Gravity.asp. Consulted 24th of June, 2014. 27. Hunter, E. H., & Hunter, M. K. (1978). The indoor garden: design, construction, and furnishing: Wiley. Consulted 16th of March, 2014.
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Figures Figure 1. Varias, L. (2011). AirDrop Irrigation System Makes Water Appear out of Thin Air, Charges Nothing for the trick. http:// technabob.com/blog/2011/11/09/airdrop-irrigation-system/. Consulted 24th of June, 2014. Figure 3. Hill, C. (2011). Capillary Thread-Moss Bryum Capillare. http://wildedinburgh.tumblr.com/post/4062512002/ capillary-thread-moss-bryum-capillare-calton. Consulted 24th of June, 2014. Figure 4. Econo (2008). What is it? http://www.equilicua. com/media/ftp/equilicua-econo-booklet_en.pdf. Consulted 24th of June, 2014. Figure 5. Lummerich, A. (2009). Fog Catchers Bring Water to Parched Villages. http://news.nationalgeographic.com/ news/2009/07/090709-fog-catchers-peru-water-missions/#. Consulted 24th of June, 2014. Figure 7. Kisan (2010). Drip Irrigation System. http://www. kisangroup.com/products/irrigation-system/drip-irrigation.php. Consulted 24th of June, 2014. Figure 8. Fipps, G., Dainello, F. (2014). Vegetable Resources: Chapter V: Irrigation. https://aggie-horticulture.tamu.edu/ vegetable/guides/texas-vegetable-growers-handbook/chapter-virrigation/. Consulted 24th of June, 2014. Figure 9. Crabapple LandscapeExperts (2014). Tips for Back Yard Sustainability + Water Conservation. http:// crabapplelandscapexperts.blogspot.nl/2013/05/tips-for-backyard-sustainability-water.html. Consulted 24th of June, 2014.
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Figure 10. Gardenerâ&#x20AC;&#x2122;s Supply Company (2014). Flat Soaker Hose. http://demandware.edgesuite.net/sits_pod10/dw/image/ v2/AABF_PRD/on/demandware.static/Sites-Gardeners-Site/ Sites-GSC_Products/default/v1403523582081/Products/37-904. jpg?sw=840. Consulted 24th of June, 2014. Figure 16. Montyâ&#x20AC;&#x2122;s Plant & Soil Products (2010). Rain Barrel, Tomatoes, and Herbs. http://mymontys.com/wordpress/wpcontent/uploads/2010/08/2-25-rainwater.jpg. Consulted 24th of June, 2014. Figure 18. Voeten, J. G. W. F. (2014). Benefits and Functions of Urban Green SHFT Smart Innovative Concepts. Consulted 16th of March, 2014.
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Are you an architect/designer looking at different watering techniques for your new green building design? If yes, then, this manual is for you! This document is intended to be used as a catalogue of watering techniques used in a green building system. The need for new innovatives sustainable solutions has helped promote the use of green building features. However, is a green roof really more sustainable? Among all the great benefits stands the fact that you need to feed it and maintain it. Improper maintenance and wasteful techniques can end up making your green system not only unsustainable but also more expensive. Water is the main resource green systems use for their development. This is the reason why the way we provide water to the system is fundamental for the sustainability and net costs of the overall green system.