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How to cite this article: Sansen, M., Martinez, A., & Devillers, P. (2021). Mediterranean Morphologies in Hot Summer Conditions: Learning from France’s “Glorious Thirty” Holiday Housing. Journal of Contemporary Urban Affairs , 5 (1), 19-34. Journal of Contemporary Urban Affairs , 5 (1), 19-34. https://doi.org/10.25034/ijcua.2021.v5n1- 2
Journal of Contemporary Urban Affairs
2021 , Volume 5 , Number 1 , pages 19 – 34
Original scientific paper
Mediterranean Morphologies in Hot Summer
Conditions: Learning from France’s “Glorious
Thirty” Holiday Housing
*^1 M.Sc. Marjan Sansen , 2 Dr. Andrés Martínez , 3 Dr. Philippe Devillers
1,2 and 3 (^) Montpellier National School of Architecture, France (^1) Email: marjan.sansen@montpellier.archi.fr , 2 E mail: andres@andresmartinez.es (^3) Email: philippe.devillers@montpellier.archi.fr
ARTICLE INFO:
Article History: Received 5 May 2020 Accepted 7 June 2020 Available online 1 July 2020 Keywords: Morphology; Mediterranean; Environmental Assessment; Additive Architecture; Holiday Housing.
ABSTRACT
Climate change and rising temperatures lead to an air-conditioning
proliferation in the summertime of the Mediterranean regions. This study
links urban morphology to the microclimate. It claims that a lesson can be
drawn from holiday housing morphologies designed with an additive
approach during the “Glorious Thirty” French coastal development (1946-
75). It is based on a morphological analysis of four case studies, with on the
one hand re-drawing and site visiting, on the other hand, assessment of
environmental performance through key parameters: Absolute Rugosity,
Compactness Ratio, Building Density, Mineralization, Sky View Factor (SVF)
and Height/Width (H/W) Ratio. Compared to literature reference values of a
traditional courtyard morphology, the case studies are less compact and with
a lower H/W Ratio (higher SVF), but they are less mineral than a historic
medieval city centre. This research contributes to the search for semi-
collective alternatives (for example additive morphologies) to individual
housing in peri-urban areas, with high environmental performance in the
This article is an open access summertime.
article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license This article is published with open access at www.ijcua.com
JOURNAL OF CONTEMPORARY URBAN AFFAIRS (202 1 ), 5 ( 1 ), 19 - 34.
https://doi.org/10.25034/ijcua.2021.v5n1- 2 www.ijcua.com Copyright © 2020 Marjan Sansen, Andrés Martínez, Philippe Devillers.
1. Introduction The “Glorious Thirty” - 1946 to 1975, a depiction of the thirty years of economic boom and the beginning of paid holidays for everyone denotes when mass tourism was born, consequently providing a huge demand for holiday housing on the Mediterranean coast. It is a period of great excitement and experimentation leading to a “new” architecture occasioned by new technologies such as reinforced concrete, and by a reaction to the Modern Movement, the CIAM (Congrès International d’Architecture Moderne) and its * Corresponding Author: Montpellier National School of Architecture, France Email address: marjan.sansen@montpellier.archi.fr
functional city which is typified by standard mass housing and functional urban zoning (Duport, 2015). As a result, the Mediterranean Coast and this new program are used as an experimental laboratory by several avant- garde architects (some affiliated with Team X – the young generation of architects that organized the 10th CIAM congress). They intend to combine rational minimalist architecture (new technologies) with architecture in due consideration of the site and the environment (sun, wind, nature). They search for an architecture that repeats similar elements to facilitate construction and minimize costs and assemble housing types or units. This brings to the fore the concept of “ Additive architecture ” which, according to the words of Jørn Utzon (Lukovich, 2018 ) describes architectural projects based on growth patterns, through the assembly or addition of similar elements. Several of those avant-garde architects from the “Glorious Thirty” mention the use of vernacular (mountain) villages as references for morphologies. For instance, J. Aubert and A. Lefèvre were inspired by Kabyle mountain villages. G. Candilis specifically quotes Avilcar in Cappadocia, Turkey. Consequently, based on the knowledge of vernacular architecture and personal intuition, additive morphologies are designed specifically for the summer. Were they pursuing solely a non- monotonous image, by fear of mass production monotony? Or did they study the thermal functioning in the summer heat and apply their findings as design strategies? From the foregoing, the current study researches if the above morphologies are efficient in summer and how they react under hot summer conditions. This is because there is a nexus between urban morphology, urban microclimate, and energy use (Adolphe, 2001; Taleghani, et al., 2015). The reviewed literature, as a result, treats morphologic and geometric indicators to study this link (Adolphe, 2001). The current research, therefore, uses an integrative approach by simultaneously considering thermal and microclimatic functions, as in the case of Jamei, Rajagopalan, Seyedmahmoudian, and Jamei ( 2016 ) and Ratti, Raydan, and Steemers ( 2003 ). In this case, the retained indicators are Absolute Rugosity, Compactness Ratio, Building Density, Mineralization, Sky View Factor (SVF), and Height/Width Ratio. Further, many studies are based on what is known as “urban canyons”, or a symmetrical section of a certain length (Oke, 1988 ). Unlike the current study, they mainly focus on urban city centres. Although previous studies have been undertaken from a historic and an architectural point of view, their environmental functioning in the summertime is yet to be evaluated (technical and engineering point of view) hence a knowledge gap. The current research, therefore, focuses on this area since individual housing and sprawl are still prevailing in France’s Mediterranean region because up till today, new individual housing is still in demand. The current study broadly contributes to the search for semi-collective alternatives (for example, additive architecture) to individual housing in peri-urban areas. The hypothesis is that these additive residences have a positive environmental performance during hot summer conditions, thus providing a certain cooling effect. The specific objectives are to assess the environmental performance of four additive morphologies, to compare them, and finally to relate them with the results of the literature review. As this is done, the “urban canyon” approach, that evokes city centres is applied to peri-urban additive morphologies.
2. Materials and Methods Four case studies in Mediterranean France have been undertaken, all avant-garde manifestations of a reaction to the Modern Movement: additive architecture, designed with the environment. The case studies were re- drawn using Archicad software, based on cadaster plans, architects’ plans, and aerial pictures. This information was completed with on-site fieldwork. The drawings and 3D models were used for morphology analysis and parameter quantification. Comparison to research reference values allowed environmental assessment. To give a “complete” environmental assessment, there were parameters related to all four climatic aspects: wind, temperature, humidity, and solar radiation (Adolphe, 2001 ). Although street Orientation and Porosity are also key parameters, they were not examined in this paper since their method of quantification was not satisfactory. Rugosity describes how the wind is influenced by obstacles. “ The higher the rugosity , the
Table 1. Parameters and their expression used for the environmental assessment. Name Definition Units ref Absolute rugosity R (^) 𝑅 = 𝑉𝑏 𝐴𝑡 m (^) (Adolphe, 2001) Compactness Ratio Cf 𝐶𝑓 = 1 𝑉𝑏^ ∑^ 𝑆𝑒𝑖 𝑛 𝑖= 1
- (^) (Ratti et al., 2003) Building Density (^) 𝐵𝐷 = 𝐴𝑏 𝐴𝑡
- (^) (Adolphe, 2001; Tadi et al., 2017) Mineralization M (^) 𝑀 = 1 𝐴𝑡^ (𝐴𝑡^ −^ ∑^ 𝐴𝑢)^ % (^) (Adolphe, 2001) Ab Total area of the buildings’ footprints (m^2 ) At Total area of the selected site (m^2 ) Vb Total volume of the built area (m^3 ) Sei Envelope Surface of building i (m^2 ): façades plus roofs, without underground and adjacent walls Au Water and Vegetation Area 3. Case Study Presentation Occitanie’s coast, on the Westside, was characterized by mosquito infestations, winds and wine culture. It was a rough 180km strip of sand that thousands of tourists passed every year on their way to Spain or Italy (Figure 1). To transform the region from pass-through to stay- in, the French government initiated its development into a mass tourism destination. A comprehensive undertaking, called Mission Racine , named after the project’s coordinator, Pierre Racine, was consequently established for developing five villages and protected natural green zones between 1963 and 1983. The planning process went hand in hand with extensive sanitation, draining, and infrastructural works. The Chief Architect, Georges Candilis, designed one of the villages, Leucate-Barcarès and two of the case studies (Village Grec and Ginestou). Although they are private property, they are connected to and part of the urban network which is accessible to everyone. To date, most of the houses are secondary holiday houses, but some of them are inhabited all year round. Leucate has a temperate Mediterranean climate, with warm hot summers (33,8°C in June), temperate winters (-1°C in January), and strong North- West winds during the summer months. Figure 1 presents the location of the case studies. Figure 1. Case study location and photographs. (1): Village Grec in Leucate; (2): Ginestou in Leucate; (3): Gaou Benat in Bormes-les-Mimosas; and (4): Merlier in Ramatuelle
The Eastern part of the coast (PACA region) has a very different geography with rocky seashores and garrigue vegetation (scrubland). It has been developed mainly through private initiatives. The accent lay less on economic and low budget mass building. Currently, Gaou Benat and Merlier are two private residences, closed communities with a checkpoint at the entrance. Very few people live there all year round and the houses are mostly used as secondary residences (as holiday housing). PACA has a temperate Mediterranean climate as well, with warm hot summers (35°C in May) temperate winters (- 2,8°C in December), and strong NNW, SE, and SW winds during the summer months. All case studies, apart from the Ginestou, are labelled “Patrimoine du XXème siècle” (label of the Ministry of Culture and Communication for remarkable architecture in France) for their remarkable architectural value. Ginestou received the notion of “exceptional” architecture in a patrimony study of Leucate City. 3.1. Case Study 1: Village Grec, Leucate, 1968 Figure 2. Village Grec. Left: Ground floor with pedestrian street widths and SVF locations; Middle: first floor Right: schematic diagram of the assembled “T” units Bottom: Section A. Red line: mean building height; Blue line: Absolute Rugosity or mean urban canopy height 0 10 20 30m P 3,00 m esplanade 8 m shelter over courtyard sea 0 10 20 30m house : T-shaped unit placettes - squares P 0 10 20 30m 1 2 3 4 5 6 7 8 109 A 70,5 m 0 10 20m
have a ground floor. They are grouped by 10 or 12 in long blocks (except for two smaller blocks). Like in Village Grec, cars are parked in the parking lots by the residents, before they head to the village on foot. Pedestrian streets are 3m wide, except for two, which is 4.3m (Figure 3). Like in the Village Grec, hedges board both sides of the streets, although they are less high here. And in the same way, the original design foresaw large green spaces in the courtyards. Courtyard walls are between 1m and 2m high, often with perforated parts to let air pass, and vary from house to house. Besides those, the village has a quite monotonous and repetitive, almost boring, character. 3.3. Case Study 3 : Gaou Bénat in Bormes-les-Mimosas, 1958 Figure 4. Gaou Bénat: Left: Ground floor plan with pedestrian street widths, slope contour lines, and SVF locations Right : schematic diagram of the strip assembly of units on a slope Bottom: Section A. Red line: mean building height; Blue line: Absolute Rugosity or mean urban canopy height The main concern for this residential area was to preserve the existing landscape, to create an “ architecture of disappearance ” as the guardian poetically put it during fieldwork (Figure 4). This was Jean Aubert’s and André Lefèvre-Devaux’s challenge when they were called upon for the development of the Cap Bénat. The question was how to build without 65 m
P 16 m
0 10 20 30m 20 30m 3,00 to 3,20 m placette - square (10m) 1,45 to 1,80 m out of study area : forest path / car road sea view
stairs house 0 10 20 30m 3,00 to 3,20 m placette - square (10m) 1,45 to 1,80 m out of study area : forest path / car road sea view 1 2 3 4 5 6 stairs P P house A
being seen, using slope and vegetation. They developed a set of regulations (called the “Cahier des charges”), with sketches and text, based on views, integration into the slope (maximum height 4.5m) and intimacy between houses. Besides, the regulations stipulate climatological aspects, like the positioning of courtyards between the house and the slope for wind and heat protection; or the troglodyte-like covering of roof terraces with earth and vegetation for coolness. The study area (sector G1 or the “Hamlet of the Minotaure”) was designed and built to illustrate those regulations to promote sales. It was the first of six hamlets and the most experimental one. Later on, parcels were sold and constructed individually. Until now, every construction has to correspond to the “Cahier des Charges” and to be approved by a congregation of architects. 36 houses are carefully positioned into the slope (Figure 4). They are oriented East and South-East, towards the Eastern sea view, and only have a ground floor, often stacked at different levels and partially underground, so that views are not hidden by neighbouring units. Houses are juxtaposed, following contour lines, parallel to the slope, and forming a strip. Most of the houses are offset of the road, but enclosure walls, containing terraces and yards, border the streets. Car parking is situated on the West along the main road that follows the contour line of the slope and that leads cars through the village. Secondary and smaller pedestrian roads or stairs radiate from here. The village centre is a “placette” or square. This results in an irregular, loose and very green tissue, attached to an irregular street network. 3.4. Case Study 4: Merlier in Ramatuelle, 1958- 1965 Figure 5. Merlier. Left: ground floor: partial underground units, public pedestrian space in black Right: first-floor plan: pedestrian street widths and SVF locations Bottom left: schematic diagram of the grid assembly of units on a slope; Bottom right: Section A. Red line: mean building height; Blue line: Absolute Rugosity or mean urban canopy height Merlier’s challenge was to create holiday housing respectful of the environment that could serve as an example of other vacation developments. These were the main concerns of the private landowner, Simone Volterra. Site visit and observation led to the idea to locate Merlier and four other villages in the hills’ folds and creases so that they would not be visible in 0 10 20 30m 0 10 20 30m 2,7 to 3,20 m placette - square > 5m 1,9 to 2,3 m out of study area :forest path / car road sea view P stairs P 1 2 3 4 65 7 8 9 other: 3,7m and 4,65m ground floor : public space buildings' first floor A 0 10 20 30m 2,7 to 3,20 m placette - square > 5m 1,9 to 2,3 m out of study area :forest path / car road sea view stairs P 1 2 3 4 65 7 8 9 other: 3,7m and 4,65m ground floor : public space buildings' first floor A 141 m 33 m P P 0 10 20 30m
M.Sc. Marjan Sansen, Dr. Andres Martinez, Dr. Philippe Devillers 28 4.1 Absolute Rugosity R (Table 2 ) The higher R, the more wind speed is reduced due to the morphology. Merlier has the highest R, meaning wind will be slowed down more. Gaou Benat has the lowest R, so the wind will be less impacted. 4.2 Compactness Ratio Cf (Table 2 ) Merlier stands out with the lowest value (0.64), which is rather surprising since it does not look compact at all with its large cantilever overhangs. They are largely exposed to climatological elements; the grid assembly causes different street widths and thus units are only partially aligned, increasing the envelope area even more. The low value can be explained by the slope and the presence of partially underground ground floors and walls. Besides, adjacent houses have common walls on the ground floor. The first floor, on the contrary, has little common walls. The other three case studies have similar values, for very different reasons. Ginestou has some adjacent walls and no first floor. Village Grec has more adjacent walls on the ground floor, but a very irregular layout on the first floor (with very few adjacent walls). Gaou Benat has few adjacent, but several underground walls, due to regulation proscriptions (courtyards between houses for intimacy, and between slope and houses). 4.3 Building Density - Mineralization M (Table 2 ) Gaou Benat stands out for its low densities (17%) and its low mineralization (59%), compared to the case studies in Leucate. All four have different kinds of green. Gaou Benat is a natural green site, with some houses and streets carefully integrated and a low Building Density. Green is omnipresent and intermingled with the buildings. Village Grec and Ginestou are the opposite: a mineral site, with green carefully integrated. The result is small-scale green (like lace), due to a high Building Density and small units. All streets are boarded with hedges and shifted or missing units are green spaces. Ginestou has a high number of green courtyards (private green). Merlier, at last, combines both: natural green surroundings, and small-scale green within the grid (planters on all terraces and courtyards are part of the initial design). 4.4 SVF and H/W (Table 3 and Figure 6) Although the photographic method does not cover the entire residence, it clearly shows different tendencies or characters for every residence. Table 3. A selection of SVF, in increasing order. The fish-eye photographs are in the direction of the street (North up). The dotted line on the sections shows the visible element on the fisheye photograph, which is used for H/W. The first value of the covered passage is not considered for further interpretation. **Location and street width Section SVF (from low to high) H/W Gaou Benat
3,20 m** A covered passage under house 0,
**Merlier
2,00 m** Stairs between two buildings 0,
320 210 450 225 200 320 145 140 165 100 58 7 37 0 200 48 1 23 3 courtyard
JOURNAL OF CONTEMPORARY URBAN AFFAIRS, 5 ( 1 ), 19-34/ 2021
**Merlier
2,30 m** Stairs between two buildings 0,
**Village Grec
4,50 m** Between an access courtyard and an offset unit 0,
**Village grec
3,00 m** Between a unit with a terrace on the first floor – a unit with a first floor (^) 0,
**Ginestou
3,00 m** Between two units of same height 1. **Gaou benat
4,50 m** Between hedge and terrace wall - Main car and pedestrian street
230 58 7 37 0 200 48 1 23 3 courtyard 300 450 155 300 265 580 228 180 courtyard courtyard courtyard 300 450 250 160 155 300 265 580 228 180 courtyard courtyard courtyard 300 300 320 175 200 320 155 courtyard 320 21 0 450 22 5 200 320 145 16 5 14 0 100 0, 0, 69
of 1.85 (Village Grec number 6 – Table 3 ) can have a higher SVF (0.39) than a section with a low courtyard wall and H/W 1.53 (Village Grec number 7 – Table 3 ): SVF 0.29, because of the hedges. Trees also have a large impact on SVF. The vegetation might be part of the residence’s public areas or part of the private courtyards. The smallest SVF of the Merlier (0,10) illustrates the latter with private vegetation from the neighbouring courtyard covering the passage. 4.5. Comparaison (Figure 7) It is not possible to point out one residence and label it the “best environmental performance” in hot summer conditions since the link between morphology and microclimate is too complex. It is possible though to compare their parameters and to indicate the residences that are more likeable to have a positive effect in hot summer conditions concerning these parameters (the lower the values, the better, except for the H/W Ratio). Figure 7. Case study comparison. The residences with the most positive effect in hot summer conditions are the ones with the lower values. Gaou Benat stands out because the wind has fewer obstructions (low Absolute Rugosity) and it’s greener (low mineralization). Merlier stands out because it has the lowest Compactness Ratio. Gaou Benat stands out because the wind has fewer obstructions and it’s greener (low mineralization). Merlier stands out because it has the lowest Compactness Ratio, the lowest SVF and the highest H/W Ratio.
5. Discussions and conclusions The obtained Absolute Rugosity R values (0.54 to 1.47), are lower than the reference value of the historical city centre of Toulouse: 7.1 (Adolphe, 2001 ). This makes sense since historical centres have several floors. They can be compared though to the reference value of 0.8 for a suburban area of Toulouse, with a majority of individual houses (Adolphe, 2001). This value alone is not very representative of the subtle design strategies that have been implemented in the residences to favour air movement: brick-on-the-side-walls and courtyard walls with openings for air movement, balconies with offset walls to let air pass… Further study will add other values, like porosity, roughness length, street orientation and main wind directions. The obtained Compactness Ratio Cf values (0.64 to 0.77) are higher than reference values of 0.584 for a traditional courtyard morphology (like central Marrakech with 9m high houses) (Ratti et al., 2003). They are also higher than 0.404 for more modern urban morphologies ( floors, 9m high, pedestrian streets without cars). If we would imagine an individual house with the same volume as a Merlier unit, with two floors and a rectangular floor plan of 8 x 10m, the compacity ratio would be 0.61. Again, the obtained values are higher. For the same volume as the Ginestou, with a single 0 0, 0, 0, 0, 1 1, 1, 1, Absolute Rugosity Compactness Ratio Cf Building Density Mineralization M Village Grec Ginestou Gaou Benat Merlier
rectangular floor of 6 x 9m, the compacity ratio would be 0.87. This individual house with one floor would be less compact than the additive grouped housing. So, the additive case studies are not compact at all. High Compactness Ratios mean a large envelope surface in direct contact with environmental conditions. Low compacity means less heat loss in wintertime and less heat gain in the summertime. So, in general, low compacity is favoured. This was also the hypothesis used for this study. But is low compacity always better? Ratti et al. (2003) claim that higher compacity, in warm climates, can also mean a higher wall mass, that can function as a heat sink. This means that, when combined with inert walls and high diurnal temperature swings (large temperature difference between day and night), high compacity can have a positive effect, according to this research. Further research will point out whether there are other conditions where a high Compactness Ratio has positive effects. The obtained H/W values are higher than Oke’s reference values for a mid-latitude city with 45° latitude, like for example Avignon or Lyon (Oke, 1988 ). Leucate is at 42,85°. He mentions theoretical values 0.4 as a lower limit, to allow solar access and 0.60 - 0.65 as a high limit for wind protection and shade. The measured case study values go from 0.66 – 2.08, which is higher. This means the additive residences are more adapted to hot summer conditions than theoretical mid-latitude morphologies. The measured SVF values (0.10 to 0.69) are higher than Ratti’s reference values of 0.13 for a traditional courtyard morphology (like central Marrakech with houses of 9m high) (Ratti et al., 2003 ), except for one measure in Merlier. They’re also higher than more modern urban morphologies (3 floors, 9m high, pedestrian streets without cars): 0.23, except for three measures in the Merlier. This means that the street proportions of these additive residences are more open to the sky than the traditional vernacular morphology of Marrakech. This Moroccan city centre is known for its narrow streets, which are well shaded during the day, and cool slowly at night when temperatures drop. When we make abstraction of vegetation, the additive residences’ streets are thus less adapted to hot summer conditions than Marrakech. We should keep in mind, though, that the architects’ reference was vernacular villages and not vernacular urban city centres. Compared to Adolphe’s reference values of 95% Mineralization (Adolphe, 2001 ) for Toulouse’s medieval city centre, the measured values are 22 - 36% less mineralized, or the additive morphologies are greener than historical city centres. The interpretation of results depends on the reference values. This study compared obtained values to reference values of urban canyons, that have a symmetrical section for a certain length. Many previous studies narrowly focus on (often vernacular) urban centres. Consequently, the current study compared the results to available reference values of urban centers that have a certain thermal functioning in high temperatures. Further research will need to be undertaken to explore whether there are other thermal ways of functioning, for example for village centres or green palmeraies with sparse housing. This research focused on an environmental assessment of additive holiday housing from the “Glorious Thirty” in France, with an integrative approach. Four neighbourhoods were analyzed and compared to each other, as well as to the results of the literature review. Although the residences have been studied before, from a historic and architectural point of view, their environmental functioning in the summertime has not yet been evaluated. This research, therefore, contributes to the search for semi-collective alternatives of individual housing in peri-urban areas. Acknowledgement The authors wish to acknowledge the financial funding provided by FEDER (Fond Européen de Développement Régional) – Région Occitanie for the research project “OEHM - Optimisation Energétique de l’Habitat Méditerranéen”. Conflict of interests The authors declare no conflict of interest. References Adolphe, L. (2001). A Simplified Model of Urban Morphology: Application to an Analysis of the Environmental Performance of Cities. Environment and Planning B: Planning and Design, 28 (2), 183-
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