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Score - Sustainable Construction in Rural and Fragile Areas for Energy efficiency

Guidelines for Integrated territorial Planning:
Microclimatic and environmental control through vegetation

The following guidelines come from a deep analysis of case studies, norms and regulations, in relation to the local level. This analysis is summarized in a card that can be downloaded in Italian language.

Vegetation can be an effective tool for the control of environmental and microclimatic conditions of indoor and outdoor space, thanks to the many systems available on the market; these allows to combine nature and urban fabric and to retrofit under functional and aesthetic aspects the building envelope, thanks to the integration of green façades and roofs. Green roofs are commonly classified in: intensive, semi-intensive and extensive solutions, which have different uses, stratigraphy and vegetation; for every type of green roof substrate thickness (given by the plant species used), maintenance needed, system weight, microclimatic benefits obtainable, influence on architectural aesthetic, costs, and use are different. Starting from a simple disposition of climbing plants at the base of the façade, several systems are available for vertical green. These are made by supporting structures for the growth of climbing plants or planter boxes placed at several heights with a shading function; others provide the possibility to cultivate species naturally not suitable for growing on vertical surfaces, thanks to the disposition of pre-vegetated panels, defined as living wall systems. Greening the building envelope allows to create better microclimatic and environmental conditions, reducing also the effects of climate changes. The integration of green façades and roofs at the building scale entails a reduction of resources due to a possible improvement of the building envelope thermal behaviour (cooling capacity, insulation, thermal mass); at a larger scale vegetation allows to mitigate the urban heat island phenomenon, which is responsible of dis-comfort situations and consequently of high energy consumption for air-conditioning, relevant aspect in the Mediterranean climate. Vegetation contributes to an air quality improvement, with respect to fine dust and pollutant gases (CO2, NO2, and SO2) absorption, with positive effects also on the quality of indoor environments. The integration of vegetation can offer the opportunity to improve also the aesthetic of buildings, besides the functional aspects, with also possible positive social implications. Green façades and roofs can provide a renewed aesthetic to buildings characterized by important state of decay and, at least in part, reduce the visual impact in high quality landscapes, besides improve the building envelope performances, the functional characteristics, and the environmental conditions.
The difficulty of building integration of vertical and horizontal greening systems depends on several factors; considering the environmental and microclimatic benefits described, it is recommended the overtaking of these difficulties, which is often not very complex. These difficulties can be caused by a restricted diffusion of greening systems (and by the resulting preconception with respect to maintenance and economic burden), by insufficient clearness of the local regulations on the microclimatic and environmental benefits obtainable and on the plants species parameters of choice. The reduced diffusion of this technology is also due to the absence of economic supporting programs or specific regulation aimed to support a wider diffusion in urban areas. Finally, integration difficulties connected to a more or less adaptability to pre-existing buildings can be noticed.
The diffusion in the local context of retrofit interventions with vegetation for the environmental and microclimatic control, considering the weakness defined, could be implemented thanks to the following actions:

 Indication for the Bio-construction Action Plan

 Pursuant to the guidelines written above, here are synthetically reported the criteria/examples for pilot projects to be financed in MED territory, in relation with the specific treated theme. These criteria/examples, together with the ones resulting from all the themes of eco-construction tool matrix, will make up a Bio-construction Action Plan for each partner countries.

Possible criteria for MED bio–housing quality certificate

Usually the certification tools provided by the main organizations don’t directly consider vertical or horizontal greening systems. In any case under many headings (and relative points) it is considered that the integration of vegetation, as it happens for LEED Italia and Itaca Protocol, the Italian version of “Green Building Challenge” (made by a network of 25 countries), which are two of the most diffused and known Italian rating systems. For example, with the Itaca Protocol, the integration of vegetation (green roofs and ground treatment with vegetation in the vicinity of the building) can be considered for the calculation of only two standards. In the part regarding the environmental burden the performance indicator of the urban heat island criterion (category:  environmental impact) is calculated with the relation between shaded or greened surfaces and the total surface of the intervention parcel (external area + roofs); in the same rating field also the criterion related to the ground permeability is calculated considering the presence of vegetation in the project area, even if, for this parameters, roofs are not taken into account. Also, inside LEED, vertical greening systems are not mentioned, but green roofs are considered for several parameters regarding the intervention site sustainability. Green roofs and vegetation on the ground can be considered for the site development (habitat protection and restoration, open space maximization), for the qualitative and quantitative rainwater management, and for the mitigation of urban heat island.
The effects of vegetation on the building microclimate are several; these could be considered in certification systems. Some of the effects are still not quantified, however it is believed that more space could be given to greening systems and especially to vertical green (which is not mentioned in any of the examples given) for the many advantages that these systems offer. 

Case studies

The case studies relative to “Microclimatic and environmental control through vegetation” are given inside the card that can be downloaded from the SCORE web site in Italian language.

Download PDF (Italian language)