2014 11 13 TRADUZIONE SU TEMPLATE - people.unica.it

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ADVANCED TECHNOLOGY, QUALITY AND NATURAL MATERIALS

EFFICIENCY IN THE MEDITERRANEAN CLIMATE

Gian Piero Cossu1*, Gianraffaele Loddo

2, Daniela Ludoni

2, Marco Pittaluga

2 and

Eleonora Solinas2

1: Department of Civil Engineering, Environment and Architecture (DICAAR) Faculty of Engineering and Architecture

University of Cagliari

Via Marengo 2 - 09123 Cagliari (CA) - ITALY

e-mail: [email protected], web: http://www.unica.it

2: Department of Civil Engineering, Environment and Architecture (DICAAR)

Faculty of Engineering and Architecture

University of Cagliari Via Marengo 2 - 09123 Cagliari (CA) - ITALY

e-mail: [email protected], [email protected], [email protected], [email protected]

web: http://www.unica.it

Keywords: Sustainability, Tradition, Innovation, Hygrothermal performance

Abstract In the current building experience of the very technologically advanced part of the

planet, concept of Sustainability, has brought to more suitable solutions based on LCA managing

models, from material and component dimension to the accomplished built object. Nowadays,

buildings and dwellings have become dynamic and elaborate organisms. We are leaving behind

ourselves the Modern idea as Architecture as an energetic machine to move towards new

paradigms, new models based on local and energetic efficiency, innovation, costs attention and

resources utilization that might improve people life quality, even in the social dwelling size. To

achieve our purpose, we have taken environmental standards as project assumption in order to

get closer in the interactions between building as a complex system and as ecosystem. We can

apply the same sustainability assumptions in common practice and fast building-up procedures,

combining vary types of durability, reversibility, reliability even with self-construction building

procedure. As result of this way of thinking, the trial project, of a 35 sqm building module, starts.

Moreover, in this study, takes place the electrochromic (EC) glass experimentation, shifted from

continental to the mild Mediterranean climate. Studies started up in 2008 by a university and

professional research team and have been focus on compatibility condition of EC selective glass

with local materials production, answering to precise economical and environmental

requirements in a more cost/benefit awaked vision for social dwelling target. Local materials

supply, production quality, knowledge of the habitat and of the local building techniques as

brought to privilege poor materials as straw, wood, cork and wool. With these basis, the module

can fulfill different demands and functions, depending on the proper case, from the complex

building type can be suitable as social dwelling module as well. The aim of this abstract is to

show the development of the research project lead by Cagliari University DICAAR, merging the

results of the use of EC glass in mild climate, with high quality performance solutions for builder

company and local producers in order to test these solutions in vary of fields.

Gian Piero Cossu, Gianraffaele Loddo, Daniela Ludoni, Marco Pittaluga and Eleonora Solinas

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1. INTRODUCTION

"The problem of minimum housing is the basic minimum of space, air, light, heat

necessary for man to be free for the full development of its vital functions, a minimum

vivendi and not a modus moriendi" [1]. In this way, W. Gropius described in Frankfurt, in

1929, the minimum parameters required for an individual to be in complete harmony with

his accommodations. Since then, the evolution of the current housing has led to more

appropriate connotations: from functional space to place, combining art, aesthetics,

research and technological experimentation and the study of materials. In other words, the

concept of living creates the link between housing and user, including interior units and

person. Here, the evolution mainly concerns the continuously development where user

transforms and adapts the internal space in the direction of a more fitting and flexible way

of living. The house is the principal place of social and urban roots and starting point of

all relationships that can interweaving natural and urban environment, city and region.

The house is, at the same time, tangible necessity related to social welfare and social

integration, which provides evaluating index of the relationship between insufficient

financial resources and minimum needs of housing services. The housing problem is

involving more and more segments of population. It concerns different space and time

dimensions in relation to the various characteristics of the user, needs and types of residential

accommodations. In particular, attention is focused on those individuals that literature

indicates as the new poor. They are individuals who, despite having a spending power, have

difficulties in finding suitable housing. In spite of been out of the typical social housing

categories, because of the crisis effects generated in employment, economic and housing, also

in personal issues, they show a significant character of vulnerability. They have higher

availability than the poorest social classes, but do not offer guarantees to enter the housing

market with typical systems of financing and facilitation that refer to credit institutions. Only

recently and only in aware areas is getting more attention the today's changing conditions of

society, as understand the conditions of users access, or providing answers to homelessness.

This requires attention to current practices: it is not merely to provide a suitable housing

condition but to integrate these population groups with targeted actions in social and urban

audience. In summary, the intent is to use social housing as an instrument of flexibility, social

progress and link of our cities, identifying new settlement patterns to meet the latest demands

of integration. Most virtuous experiences of our Country concern temporary residences and

self-buildings. This last point brings attention to those social groups of the new poor, covering

the gap between traditional social housing and housing market.

2. SELF-BUILT SETTLEMENT MODELS AND SUSTAINABILITY

Design process, materials and components selection, technical and technological applications

require a careful assessment of the reference scope. Cost of construction, time of execution,

practicality and ease operations impose to carefully calibrate the possible solutions for

ensuring terms of convenience, expressed with a reduction of 30-40% of the total cost of

construction due to the absence of manpower. This contrasts with almost total lack of

competence of the self builder which necessarily requires assistance in the phases of design,

choice of materials, use of local building traditions techniques. The usual types of self-


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construction descended from the level of the technique, whole or partial, by the organization

of the users, the available technologies and techniques and from the site location. Mostly

common are terraced house from one to maximum three levels, or isolated and duplexes

houses. All types with characters of very flexibility of served spaces and service spaces,

depending on family evolution. This form of adaptation is the first footprint of the

sustainability of social housing homebuilt. Operating references across the Country are

concerned in techniques transfer from specialized workers of the tradition to self-builder

users. In fact, there is not yet a specialized field of industrialized building which follows with

interest these new self-constructions. The aim is a constructive process facilitated by adopting

technologies that have reduced structural complexity, in order to simply assembly and

connections, making the artifacts manageable and light, so to facilitate different phases of

execution. Considering differences between characteristics of the traditional construction site

and the simplified practices of the self-construction, attention moves towards specific factory

elements: vertical and horizontal closures and, therefore, housing as envelope and hisbearing

system. Taking inspiration from traditional building systems, for the vertical closures, blocks

are the best solution. These blocks have relevant thermo-mechanical resistance, supported by

thermo-insulating, and can be use as panels or with the function of formworks for concrete

lay. Moving toward more sophisticated system for our Country, the focus is directed towards

experimental skeletons carrying more by wood than steel. With reference to the prefabrication

of light and manageable components and subcomponents, the intent is, on one side, to

facilitate the practice, and on the other, to control the incidence of these products costs on the

final cost of the intervention. It will be desirable also the involvement of companies in the

production and marketing of products suitable specifically for self-construction. Talking about

partitions, is common to use the same blocks of external closures, even if reduced in thickness

and, without insulating layers. For horizontal closure is generally used a truss or a warp on

which the stratification of coverage is posed, with of a thermo-acoustic insulation and

waterproofing. The insulating materials in use are often rigid panel that facilitate assembly

operations. Systems, like electrical installation, require accurate design by professionals,

avoiding interference with the internal distribution and the functionality and flexibility of

spaces, channeling them with the aid of blocks systems.

Self-building involves even evaluations in terms of environmental impact, especially when

the self-build product represents an element of relationship between the spatial scale and that

one of the building component. Beyond the impact of building system on the resources

consumption yet available, focusing on buildings, or techniques with low environmental

impact and energy, would benefit the economies of operation and maintenance, with regard to

the full life cycle of the house. These aspects are also related to a targeted approach: the use of

local and traditional materials, such as clay, straw, bamboo, natural insulation, plaster of lime

and ecological paints. It is possible to involve the use of natural energy resources such as

solar, wind, heat from the ground, leading to a design totally directed to environment. The

concept of cycle based on natural processes can be applied here as a LCA approach from

concept of the homemade until his disposal, including recycling of discarded materials and

landfill disposal of those no longer in use. Even the evaluation of costs and impacts generated

by different and successive phases of the building process spans the whole cycle. The choice

of materials is set between the different available types: natural materials, minerals, synthetic


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materials do not necessarily obtained from the processing of petroleum products. The use of

Life Cycle Assessment shows that, in terms of overall sustainability, the use of certain

materials called natural, can generate an higher impact than a natural raw material of superior

performance even if not comparable. The experimental evaluation takes into account an

environmental indicator of reference: the embodied energy with to estimate the amount of

energy used to transform raw materials into building products. The process includes several

stages of production starting from raw material until the arrival at the site, without neglecting

the impact of operating costs and maintenance costs that increase the embodied energy in a

building. Following this method is possible to reconstruct an ecological assessment of a

product in relation to the different stages of the process. The character of warm temperate

climates of the Mediterranean, such as Sardinia, reflects the influence of the sea, with mild

winters and summers prolonged, attenuateing this mild climate proceeding inward. Local

building practices favored the traditional definition of housing types, using very thick walls

with high thermal inertia to ensure a summer cooling in relation to the zenithal inclination of

sun's rays. The forms of development of traditional building types and the use of more

consistent principles of bioclimatic allow to come to forms of construction and management,

in which the terms of sustainability are compared with the choices of self-construction.

Although aware that any further investigation, especially if experimental, in the field of

social, characterizes the approach to the planning and design of intervention, even before the

sustainability characters of the finished building product, the aim is to operate with a low

environmental and energy impact method. The dialogue with the context is the comparison

between performance of different types of materials and technologies. The comparison is

among materials requirements, including the selected technique and appropriate methods of

function distribution orientation of the environmental units and shading elements. These are

the basic and economic principles that self-building can assimilate, waiting for the diffusion

of a practice construction of low impact that can reduce the cost of green building products,

still too high to be suitable for everyone without distinction. Similar references check the

effectiveness of the use of prefabrication, reducing scraps of material, water consumption and

energy related to its production, namely ensuring flexibility of use and versatility of the

components, less weight and greater workability, with content management costs.

3. THE ART OF BUILDING DEPENDING ON THE MATERIAL

Architecture is the art of building in relation to the organization and performance of building

components and technologies provided by selected materials of the project. The emergence of

sustainability criteria still more shared in the practice of design, construction and

management, has allowed to spread more appropriate typological formal and technological

solutions. The method that often characterizes these solutions concerns a procedure that, from

the adoption of technical-constructive particulars, reaches for the image with a proportional

change of scale. The experimental research is managed, among factory elements, especially

the envelope, according to the most appropriate forms of technology integration related to

materials, types, construction methods and techniques of representation and processing. The

skin of the building is set up as part of a complex plant interactions. This methodology,

acquired in the building sector through appropriate forms of technology transfer, involves

different aspects of architectural experimentation. The development of this process adopts


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coherent systems based on traditional materials and innovative construction techniques of the

traditional site construction methods with low content of energy and environmental impact.

The methodological innovation concerns a building product not simply adhering to the design

performance, but more akin to the needs of the users, promoting their participation, involving

them in the structure process building up forms of self-building owned/assisted. The building

system that derives is configured on a reproducible prototype in terms of performance and

production, although not strictly standardized in series. This more full cohesion to complex

forms of environmental sustainability embraces further levels of building practice, involving

on-going quality and efficiency of materials and components of the project. Currently, the

most consistent project solutions tend to conform to a system of relations, more responsive to

the set of circumstances and contingencies, correspondences and connections of nature and

space. It does not seem, in fact, a case that buildings with traditional alternative materials, -

clay, straw, materials as recycled pallets, ... Relate to the expectations of the public. The

conflict affects building standard, usual and normal, in view of the quality of cultural

innovation and technology. Moreover, it involves the prerogatives of aesthetic architecture

highly stable and efficient, compared to the typical forms of traditional culture. It concerns

also the degree of performance and quality architectural purchased in the current balance

between resource consumption and regenerative processes of the environment, often peculiar

of the material cultures of the tradition, so as to make the major cost for the construction and

maintenance of the buildings. The input is revealed in the deepening of knowledge,

comparison of systems and alternative materials in terms of potential and benefits achieved

and high efficiency energy-environment. This alternative building form relates to the same

traditional construction, involving professionals and skilled workers, machinery and

materials, procedures, and sequences of construction.

4. TESTING TECHNIQUES AND ALTERNATIVE MATERIALS

In alternative to the current building standard, significant scope experiences involve the use of

wood, mostly in small elements, for its performance of bending and compression, for

workability, formability and ease assembly at low cost. The deepening of its characteristics

allows to give priority in the experimental phase, to the use of a balloon frame system, of

structural elements of reduced sections, allowing the easy construction of buildings of

contained dimensions. The interest in straw is motivated by inner properties of the material:

low environment impact, lightweight, insulating, availability, strong and durable, easily

workable. Although often associated with clay or adobe, straw bales plastered walls present a

risk of fire lower than wooden structures. Although these properties descend from building

materials packaging characteristics, the real issues concerns the effects on material generated

by water. The possible applications would favor products in panels or bales, reducing at this

early stage the use of unpackaged straw. At this point the problem concerns the quality

associated with the required standard for these panels and bales, also in terms of availability.

Among different systems, the initial analysis promotes a structural frame as construction

method, in which roofing is carried by a wood structure, while bales are filled between the

vertical elements of the supporting frame. This will overcome the risks associated with an

experimental technique, focusing on performance of material and building products. The

supporting frame also allows to achieve larger openings, without any conditionings in plan. In


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this experimental phase of self-built social housing, we take into account the obvious

disadvantage of lower practical experience, supporting more compatible solutions in terms of

ease of prefabrication and assembly of the building. The ability to manage appropriate

guidance and screens for large window openings, allows to introduce innovative building

solutions even in Mediterranean climate. Beyond the architectural symbolism, their

application is crucial for winter benefits and summer overheating. Appropriately selecting

type and orientation, the glass must ensure, together with the envelope, adequate levels of

efficiency according to local quality. Using the experience gained through innovative

applications of electrochromic material (EC) and in consideration of the construction

technologies applied to the building of the test rooms, one with a EC glass and the other with

conventional low-e, is expected to be achieved the objective of comparing the sustainability

and different optimal solutions of the organism on different stages of the construction process,

in terms of production, performance, durability, multi-functionality and recyclability [4], [5].

Paper and cardboard are the other materials chosen for experimental applications, although

their usage must be deepened in relation to self-building and with reference to the local

practices [6]. Although in use for the production of building elements and components like

panels, formwork, insulation and finishes, the study concerns the reference source variables,

because of the absence of official literature on the practice of self-construction in the social

context. The main innovations, especially in the use of waste paper highlighted by literature is

focused on blocks and panels bearing production and infill masonry elevation, as in the

student residence in Hale-USA, designed by G. Comstock, A. Holtz and A. Olds [2]. Here,

bales of corrugated cardboard that cannot be recycled, pressed and joined together, has led to

the construction of barns, sheds and houses for students. The cardboard is compacted into

bales from 750-1250 pounds, showing bearing capacity for foundations and for the vertical

closures. Finally, the pallet, used for support and handling industrial loads to be stored, has

been revisited to became basis form of the building organism. The experimentation sets a

variant of the frame system construction to be applied to the low-tech pallet frame whose

voids permit housing of the duct and canalizations. The study concerns laminated wood

performance on which to size pallet sections, according to different levels of usability of the

space. This allows to achieve significant results in terms of impact and durability, weight

reduction and cost, processing, simple particulars, ease and intuitive installation and

workability, and resulting in determining the commercial availability of the productive

element based certificate and above all of the elements of frame.

5. GUIDELINES AND EXPERIMENTAL PROJECT

Studies have highlighted the need to reconsider the image of many of today's urban settings:

high density, significant impacts of complexes scattered throughout the territory, with major

settlements independent of the context. These identified degradation factors, related to the

physical settlement and management of the process and of the inner structures of social

housing, can be contrasted here preparing the design approach to social housing in line with

the frame of reference. The most coherent plan could be to coordinate an integrated public-

private partnerships service management, in which the public figure oversees and operates the

supervision of the impact generated by the residential system on the environment. Recent

refurbished urban areas, propose action on small buildings up to two / three levels. The two


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levels types are able to accommodate from two to four families, or barely more in relation to

the different typological users configuration and, therefore, of the accommodation. Admitting

to continue in the definition of distribution system based on the settlement of 20-28 units of

housing, with no abstract references to urban standards and the entire system of traditional

urbanism, the definition of the project must be commensurate to the actual housing users

needs to which action is taken. From the technical point of view and connections to the

experimental goals of comparing the level of sustainability of the organism optimal solutions

built on different stages of the complete construction process, the focus is on the design of the

envelope.

A box-shaped geometric form, also with extremes of seriality, set on a link pattern, preferably

constituted by quadrangular modules. This approach allows the display of each environmental

unit as part of a total body, allowing more flexibility in housing needs and internal connection

of the service areas. This allow adjustments in contraction or expansion to the physical

limitations of the typological model chosen, made dissociating/associating the modules to

represent an element of communication between the accommodation units. According to these

hypotheses, once developed the basic building module and designed the housing, the interior

of the box is configured to meet any performance features. Thus, is expected to keep under

constant control each built form and the same modules combination which constitute the core

and any possible form of further aggregation, according to the degrees of adaptation provided

in the design phase. From the structural point of view, the same conception of each building

base module, which provides the associated member of a more complex structure in which

each link to the other modules allows reciprocity of actions and stresses, are essential for

ensuring the stability of the whole organism. All this allows to achieve the essential

requirements of simplification of the phases of ideation, test equipment, production,

installation and maintenance of the building system, while ensuring ease of assembly and

disassembly, as well as flexibility in terms of mobility and aggregation, without involving the

ability to balance the whole structure, nor its adaptability to requirements however and always

complex variables. The accommodation is combined on a module repeated along an axis,

variously based on a modular design of elements in horizontal tunnel, plans to set up a prism

form whose envelope is characterized by flexibility, multi-functionality, modifiability and

reversibility, in adherence to the intent to prepare an action compatible with the

environmental context, as well as the intentions of the experimental research in progress. The

same experimental objectives are focused on terms of practicality and speed of

implementation, of a considerable degree of reversibility and durability, reliability and

quality, with the use of compatible forms of assisted self-construction. The development of

the experimental process allows to move from the form of self-built social housing to a model

consisting of a small architectural object. It is a homebuilt front office of 35 square meters,

with bearing frame of wood and straw-bale infill.

The intent is to build this temporary building in the green areas of the Faculty of Engineering

and Architecture of Cagliari, as a form of self assisted building by students, according to the

typical activities of educational workshops. Designed in the summer to accommodate an info

point for future students of the University, the front office is a starting point to define in detail

the chosen technology for the experimental comparison.

The selection of materials and techniques is directed towards infill bales of straw and a


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balloon-frame wood elements of small size [3]. Combining different environmental units

adequately insulated and glass selective, we take advantage of the results so far developed on

the contribution of the EC in the Mediterranean. The front office has a wooden frame with

infill of straw around the entire perimeter and an internal partition wall. The internal partition

adjacent to the toilet is of equipped type for the passage of ducts, in this initial phase coated

with plasterboard elements, in addition to the necessary finishing elements, indispensable in a

service. The cover chosen is a gable roof supported by trusses of laminated wood and a

secondary order made up of wood strips. The use of different materials for vapor barrier,

thermal and acoustic insulation and waterproofing allows comparison of the initial

performance of green building materials, with reference to local production. The gable roof is

made with a clay tiles ventilated roof. Thus, the finishing touches are designed in hydraulic

lime-based plaster, providing high breathability. In doing so, a strong social connotation of

sustainability is impressed on the project of building, including its link to traditions even not

proper of the place. The impact generated in terms of project costs and of energy and

environmental efficiency of the front office and, in particular, of its envelope, allow to take as

reference the results on detailed surveys that will be acquired with the experimental

instruments by researchers. In order to ensure of self-building specifications and initially

evaluate the impact generated by chosen materials in the different phases of the building

process, attention is directed in advance of a vertical front office wall, treating it as an

experimental test of the whole. The foundation is a concrete curb perimeter of which is placed

a strip of bricks to ensure discontinuity between the foundation and straw, contained between

two currents in wood. The bearing structure of the closure is of two pillars and a beam made

of solid wood, connected to each other and with the other elements with plates and steel

angle. The infill of the lining of the pillars guarantees housing plant. Straw bales are held in

place by staples fixed to the columns and the beam above. The experimental processing

continues today with the passage from the operations sheets for the construction phases to the

simulation results with computer codes in dynamic regime to the more consistent definition of

executive intervention, planned to coincide with warmer weather (April 2015) and on the

availability and operational phases of university laboratories.

6. CONCLUSIONS

In the early steps of experimental research in progress, for the purposes and results of the

project we will achieve, the current evaluation experience motivates the interest in science

and technology, for the interest of those partners in research and same user to whom it is

directed the current analysis. Considering the contribution of multiple skills and potential of

the project implementation is easy to understand the results of an architectural practice and

building more adherent to the environment and the user. In terms of achieving reduced

environmental impact and energy efficiency of the common areas of the Mediterranean, it is

convinced that the experimental conditions will influence the course of the social housing as a

practice always more sustainable.


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Monthly average of May 2014 Humid. Rel. T room Rad. Glob.

Season: spring (%) (°C) µW/cm2

Low-E room 47,25 22,53 516,40

EC room 55,10 20,53 138,83

Table 1. The experimentation on the EC windows, conducted in the year 2013, has allowed the cataloguing

and later the analysis of all data, presented and published to the international conferences [4], [5]. Detected data show the EC thermal energy behaviour, that allows a significant consumption saving for the air

conditioning of interiors. Testing, continue during the year 2014, which we report, in the table, data

referred to the month of May, is in line with the results obtained the last year. Projecting data for the

summer period, which will after published, it’s possible to confirm the great thermal features of the EC

glass. Concluding EC glazing perform the best chance in today’s technological, among glass components

for the building envelope. His chose and use is closely related to the economic purposes about the type of

building design.

Figure 1. Student residence in Hale-USA, designed by G. Comstock, A. Holtz and A. Olds [2].

Figure 2. Axonometric view of the front office. Featured parts of the roof and the internal distribution of the

units.


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Figure 3. Details of the experimental infill straw bale: to the left, the particular della'attacco to the foundation; to

the right, the engagement of the straw bales to the upper beam.

REFERENCES

[1] C. Aymonino (by), " The house rational - Acts of Congress C.I.A.M. 1929-1930",

Marsilio Editor, Padua, Italy, 1971, Polis vol. 10, p. 108.

[2] J. M. Giagnoni, "Rural Studio: Corrugated Cardboard Pod" Materia International

Architectural Review, vol. 42, pp. 36-43, 2003.

[3] P. Lacinski, M. Bergeron, "Serious Straw Bale. A home construction guide for all

climates", Chelsea Green Publishing Company, White River Junction, Vermont,

2000.

[4] M. Pittaluga, G. Loddo, D. Ludoni, G. P. Cossu, "Performance and properties testing

of electrochromic glazing in Mediterranean climate", in Proceedings of 39th

International Association for Housing Science, Milan, Italy, September 17-20,

2013.

[5] G. Loddo, D. Ludoni, M. Pittaluga, G. P. Cossu, "Application of sustainable

technologies in the future of historic buildings: electrochromic glass", in Proceedings

of 4th

International Conference on Heritage and Sustainable Development, Barcelos,

Portugal, July 22-25, 2014.

[6] A. Rogora, D. Lo Bartolo, "Build Alternative. Materials and alternative techniques for

sustainable architecture", Wolters Kluwer, Milan, Italy, 2013.

2014 11 13 TRADUZIONE SU TEMPLATE - people.unica.it

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