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Building and Environment 45 (2010) 2709e2722

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Building and Environment

journal homepage: www.elsevier .com/locate/bui ldenv

Understanding the climate sensitive architecture of Marikal, a village in Telanganaregion in Andhra Pradesh, India

Madhavi Indraganti*

Climarc, 6-3-581, B-203, Keshav Dale Apartments, Khairatabad, Hyderabad 500 004, India

a r t i c l e i n f o

Article history:Received 6 April 2010Received in revised form30 May 2010Accepted 31 May 2010

Keywords:Vernacular architectureBioclimatic designSustainabilityArchitecture of TelanganaHot-dry seasonMarikal

* Tel.: þ91 4023305233; mobile: þ9198666 76586,E-mail address: maindraganti@gmail.com.

0360-1323/$ e see front matter � 2010 Elsevier Ltd.doi:10.1016/j.buildenv.2010.05.030

a b s t r a c t

Architecture and climate are engaged in a happy marriage in any indigenously developed settlement. Wedocumented and analysed a vernacular settlement, Marikal in composite climatic region of A.P., as part ofa large development project. Marikal’s form and structure are a result of centuries of evolutionaryprocess and knowledge transfer, reflecting a set of varying physical and nonphysical determinant forcessuch as climate and geology, religion, socio-cultural values, economics, technology and administrativefactors. It is a closely knit fabric of small clusters of dwellings comprising of thick white walls, heavyroofs, small windows and narrow streets. Many house typologies are identified. The house plansessentially vary in size, shape and detailing, but not in their climate sensitivity. They are in great harmonywith the occupation/activities of the occupant. The occupants adaptively synchronize their activities withthe spatial environmental qualities of the space.

However, the ‘house form’ of Marikal is transforming due to social forces and the availability of electriccontrols in the recent decades. Once highly climate sensitive architecture and behavioural patterns areslowly getting metamorphosed into architecture and attitudes that are irreverent to climate and context.This study calls for a code of practice balancing modernization with the vernacular.

� 2010 Elsevier Ltd. All rights reserved.

1. Introduction

Traditionally, our buildings are regarded as our third skin,clothing the second, while the biological skin is considered the first.These three skins help us maintain the deep body temperature ataround 37 �C round the year in any geographical area. In theabsence of precise temperature control measures, the role of thesettlement/building design in mitigating the vagaries of wind andweather is extremely important in providing indoor comfort [1,2].As a result architecture and climate are found to be engaged ina happy marriage in any indigenously developed settlement.

Understanding of the traditional architecture in terms of heat-humidity, air movement and light with respect to the physicalenvironment provides vital lessons for the present designendeavours. The familiar elements of regional architectural styles(verandahs, balconies, courtyards, shutters and such) are created touse the sun for warmth and light and to create shade and breeze forcooling. Climatic design lessons can be learned and inspiration canbe sought by observation of the long tradition of vernaculararchitecture [3e5]. These are important especially in the context of

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energy concerns from all around the world [6], and the alarmingincrease in air conditioning usage in the recent years [7].

Building energy consumption in India is the highest among allAsia Pacific Partnership countries [8]. With lax bye laws andgrowing pressure from various interest groups, more and morebuildings in India are being designed in aluminum and glass, onlyto be air conditioned, least concerning about the climate or context.As a result, the buildings relinquish all their local character andwear the same skin be it in the desert of Rajasthan or in the hills ofHimalayas.

On the other hand, the traditional houses of Telangana region aretypical examples of buildings adapted to the composite climate. Theaim of this paper is to evaluate the vernacular settlement ofMarikal,in terms of its architectural typology and climate appropriateness ofvarious features of the building and the settlement. This papershows how a building environment working like living organism,which is inherently sustainable through the use of various biocli-matic concepts applied in its original construction, is tightly inte-grated with the living styles, landscape and has a little wastage ofresources. The following analysis is comprised of twomajor parts: 1)a study concerning the evolution of the built environment(morphological development, site planning, cluster planning,construction materials and techniques); and 2) typological analysisof specific vernacular dwelling types and their response to climate,

1 Tc¼ 0.514 Toþ 13.5.

M. Indraganti / Building and Environment 45 (2010) 2709e27222710

based on passive design principles that are responsible for thebioclimatic character of the settlement. The evaluation of thesettlement and houses is carried out keeping in mind the environ-mental elements such asheat, humidity, airmovement and light andthe general activity pattern of the residents.

2. Marikal: a vernacular settlement in Telanganaregion in A.P.

2.1. Location and history

Marikal (N16�360 and E77� 440), a small village in Telanganaregion is in the south-western part of Ranga Reddy district in thestate of Andhra Pradesh (A.P.) in India (Fig. 1a and b). It is about120 km south-west of Hyderabad, the state capital and is 22 kmfrom Mahboobnagar, a large town close by. It is located at about5 km from ‘Ananta Sagar’ a large dry land reserve forest.

Anecdotal responses collected from the village elders of theRoyal clan during the survey revealed that, Marikal has about 600years of history. Both Muslim and Hindu feudal lords ruled Marikaltill the abolition of privy purses. Remnants of the past can be tracedin the walls of the mud fort at the center of the village and in thetemples and Dargahs in its vicinity. The village has agriculture,aqua-culture and petty vending supporting its basic economy. It hasover 2000 population (as per Census 2001) spread over an area of0.2 km2 of gently sloping terrain. It is not connected to any railwayline or major highways. As it is an interior village, the originalcharacter of the village is less disturbed by urbanization or overtcommercialization of land.

2.2. Data collection

The present analysis is based on the data collected duringa development study conducted by the author in this village during2006e2008. This study involved in depth data collection at variouslevels. The collected data is the outcome of an exhaustive house-hold survey and field work of the author, assisted by a team ofstudents of architecture. We have measured, sketched, observed,photographed, video-graphed buildings and interviewed inhabi-tants, local designers as well as public officers concerned with thevillage. In addition, we commissioned a professional surveyor toprepare the detailed village plan, as the village level detailed mapsare not available with the government. However, the large scaletopo-sheets of the region are procured from the Survey of India.This study is presented in the form of a documentary film [9], aspart of the large development project.

2.3. Climatic data

The Meteorological Department provided the climatic data ofMahboobnagar, as it is the nearest meteorological recording stationto Marikal. It has inland composite climate with four distinctseasons: Winter, summer monsoon and post monsoon. This regionhas hot-arid summers and slightly cool winters, and moderate tolight rainfall (Fig. 2). Air temperature reaches a mean maximum of40 �C and a mean minimum of 27 �C in May with a very highdiurnal range (12e15 K). The summer months have an averagetemperature of 31.3 �C, while the winter months have 25.3 �C. Theannual mean temperature is about 27.6 �C and the relativehumidity varies from 29% to 83%, while the rainfall totals 810 mmin a year.

2.3.1. Physiological objectivesSummer in Marikal is usually hot and dry (mean temperature

(To)¼ 31.3 �C, mean RH¼ 39.3%), with the period of greatest

discomfort being April to May, as the Humphreys’ comforttemperature [10] (Tc)1 exceeds the outdoor mean temperature (To)substantially (Fig. 2). Protection from conductive and radiant heatgain is thus necessary to avoid physiological discomfort in summer.Observable, the structure and built form of Marikal aptly respond tothis hot-dry season.

In the other months, especially in June and in winter, physio-logical discomfort is mitigated through clothing/activity adjust-ments and increased ventilation through the use of variouscontrols. Monsoon months are usually warm-humid (To¼ 27.5 �C,mean RH¼ 72.4%), with a mean monthly rainfall of 150 mmreceived from the southwest monsoon. Physiological discomfortdue to heat is not amajor problem in this season as the temperatureis below the skin temperature. This period is followed by north-west monsoon which receives very light spells. Winters are salu-brious although with moderate to low humidity.

2.4. Evaluation using Mahoney’s tables e recommendations

The climatic data are analysed using the Mahoney tables whichprovide preliminary design recommendations. They are groupedunder eight headings: layout, spacing, air movement, openings,walls, roofs, outdoor sleeping and rain protection [11]. Recom-mended specifications for Marikal are as under: 1) Layout: buil-dings oriented on North and South (long axis east-west) to reducesun exposure, with compact courtyard planning; 2) Spacing:compact planning with protection from hot and cold wind; 3) Airmovement: rooms double-banked with temporary means for airmovement; 4) Openings: very small openings, 10e20% of wall area;5) Walls: heavy external and internal walls; 6) Roofs: heavy roofsover 8 h time lag; 7) Outdoor sleeping: space for outdoor sleepingrequired; 8) Rain protection: rain protection not required.

Intriguing, the present settlement is found to be in completeagreement with Mahoney’s recommendations in all these aspectsmentioned above. A detailed analysis of its climate appropriatenessis presented below.

3. Climate appropriateness of the settlement

3.1. Landform and topography

Marikal is surrounded by about 15 natural lakes within a radiusof 3 km, all interconnected through natural flow of gravity. As this isa dry regionwith a little rainfall, the water table is usually very lowand the lakes are the prime source of water for human habitation,agriculture and aqua-culture. The early settlers exploited thecontour and slope of the landform to the fullest [2]. They estab-lished the village fort and the surrounding settlement at the centerof a shallow bowl shaped trough, formed by the local topography. Itis interesting to note that the lake next to the fort is at the lowestcontour, enabling it to retainwater even during prolonged droughts(see Fig. 3). Sadly, most of the lakes have dried now, excepting threelarge ones, due to poor maintenance.

Establishing the village at the bottom of a shallow trough hasother advantages in addition to having the highest water table forthe village inhabitants even in summer. As the country side isbarren, summer breezes are usually hot and add to the discomfort.Understandable, the settlement, thus developed at the bottom ofthe shallow valley retains the cold mass of air and remains pro-tected from hot breezes. The village has a gently sloping terrain,towards lakes in the south-east and has hugemasses of natural rockout crop towards the north-west (at a distance of 2 km).

Fig. 1. (a): India map showing the five climatic zones (Source: the National Building Code, 2005); (b): Political map of the State of Andhra Pradesh, indicating Marikal in RangaReddy district (a red dot in the box). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

M. Indraganti / Building and Environment 45 (2010) 2709e2722 2711

Fig. 2. The climate chart of Marikal showing the summary of outdoor environmental data recorded during 2007e2008, indicating the four seasons, and the Humphreys’ comforttemperature. (Basic source: The Meteorological Department, India).

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3.2. Morphological development

The morphological development of the settlement is under-stood to have taken place in about four stages based on the dataprovided by the families living around the fort for many genera-tions and other visual observations of the author.

The village has developed along the Bazaar Street and slowlyspreaded in the south-west direction as the bus route to Mah-boobnagar town was laid. The built form evolved perfectlyresponding to the elements of climate and other functionalrequirements. The older buildings are compact and are relativelysmaller compared to their recent counterparts.

Fig. 3. The topography sheet of Marikal and the surrounding area showing the interconnetowards the village from all sides, forming a shallow trough while enabling higher ground w(For interpretation of the references to colour in this figure legend, the reader is referred t

As shown in Fig. 4 e Phase-I, fort in the center was first estab-lished in close proximity to a lake, which is now dry and defunct.The houses adjacent to the fort are occupied by either the rulingclass or by the people serving the ruling class. These are mostlyLingayats’, Brahmins’, potters’, carpenters’ andweavers’ houses. Thefort street has become a prominent bazaar street in the secondphase and many shop houses of the merchant class, Reddy andother communities evolved along the fort street. It is interesting tonote that the Bazaar street still holds a weekly street fair (santa)every Tuesday, which is a major economic activity in the village [9].

Like many other natural settlements, the growth started aroundthe fort and spread linearly along the main Bazaar Street. With the

cted lakes (contour interval: 5 m; lakes are marked in blue). The terrain gently slopesater table and protection from hot breezes. (Source for the map: The Survey of India).

o the web version of this article.)

Fig. 4. Morphological development of Marikal: the settlement spreading around the fort and the Bazaar Street in I and II phases and along the second main road in III and IV phases.

M. Indraganti / Building and Environment 45 (2010) 2709e2722 2713

introduction of the motorable road connecting Mahboobnagartown, the second main road has come into prominence, whiledensification of the village interior continued.

Modern structures have begun to appear along the road, witha lot of commercial activity spilling on to the road. In the recentdecades, new housing colonies for the weaker sections are deve-loped along the second main road as seen in the fourth phase. Assouth-west part of the village hasmainly un-irrigated dry lands, thevillage expansion is found to be taking place in this direction. Thefort wall and one Burj (sentry post) of the fort now exist and are inruins. Fig. 5 presents the architectural character of the settlement,the site plan and a panoramic view of the remnants of the fort ina snap shot [12].

3.3. Form and site planning of the settlement

Dense clusters of small and compact tenements configuredorganically along the narrow streets and alleys form a major part ofthe settlement. As explained in Section 2.3.1, protection from drysummer is found to be the primordial consideration in the deve-lopment of form and the site planning of Marikal. It has developedin response to sun, orientation, air movement and topography asa tightly knit fabric of small housing clusters. Fascinating, thestructural form of the settlement is similar to the settlements inother hot-dry areas as observed by Koenigsberger et al. [11], Rattiet al. [13], and Saleh [2].

The villagers showed immense ingenuity in laying the streets.None of the streets in the older settlement are along the EeWaxis,except a few done in the recent times. The streets are laid along theNWeSE and NEeSW directions, while most of the buildings havetheir longer axes facing the north.

As Marikal is a dry area with very little green cover and poormonsoon, shading of horizontal surface of the streets is essential foravoiding discomfort glare, ground reflection and heat gain, to enableeasy movement of people, walking barefoot sometimes [13]. Nar-rower streets also reduce the daylight component from direct solarradiation in the streets and building interiors, which is quite high.

As a result, the sky view factor is also maintained low, which ishighly beneficial in hot-dry weather, also as observed by others[2,13] and it may limit the long wave loss at night. However, highdiurnal ranges (w15 K) usually observed in summer accelerateconductive and convective heat loss from the building at night andcompensate for the slow long wave loss due to lower sky factor.

3.4. Cluster planning

The cluster open space is regarded as a vital design element inachieving occupant comfort in Marikal. Simple residential clus-ters formed by inward looking houses are found here, which aresometimes enclosed too. These are enclosed by high compoundwalls (1.5e3.7 m high) in mud or brick construction, witha double shuttered door and a tiled sunshade laid over stonewall-plates.

The central cluster open space is also used for night timesleeping and for day time resting when shaded. The mud floorsurface of the cluster open space is usually treated in cow-dung, toavoid overheating and glare due to the ground reflection. Moreimportantly, this finish cools faster, and enables better utilization ofthe space during the day, after the sun moves away, especiallywhen people walk barefoot, or sit on the ground performingvarious activities. Rijal et al. [14] also observed lower surfacetemperatures and found better performance in mud floors.

The size and organisation of a dwelling unit around the clusteropen space varied significantly depending on the socio-economicclass of the occupant. For example, in clusters belonging to theupper classes the houses are much larger (Fig. 6) compared to thelower classes (Fig. 7). However, in lower class houses, many acti-vities like sitting, bathing, cooking, etc. also spill into the commoncluster open space.

The central open space is utilised for various outdoor activitiesdepending on the occupation of the household. For example: infishermen’s cluster (Fig. 7), the cluster open space used forrepairing the fishing nets, while in farming communities, it is alsoused for drying the farm produce, etc.

Fig. 5. (A) Bazaar Street. (B) Fishermen’s cluster. (C) A typical shop house. (D) Cluster of the lower economic class. (E) Typical Brahmin and weaver’s cluster. (F) Remnants of the fortwall located in the center of the village. (G) Site plan of Marikal.

M. Indraganti / Building and Environment 45 (2010) 2709e27222714

More importantly, the cluster open space is shared and main-tained commonly by all the households of the cluster. It is also usedfor performing marriages. Interestingly, in the shop-house clustersaround the fort area, the open space faces the Bazaar Street,enabling the shops to spread the merchandise into the open spaceduring the weekly fair. As a result, the bazaars have naturallyemerged along the well treaded path, comprising of the shophouses, and other multi storied houses, while retaining the originalcharacter of a rural habitat.

The clusters thus formed by the very organisation of thesetenements are found to be at human scale resonating the feeling ofthe neighbourhood. Children play here in safety, while women andmen engage themselves in active interaction. As shown in Fig. 6,enclosed/semi enclosed courtyards and smaller clusters organizedthemselves organically to form large clusters, forming a hierarchyof open spaces from private to semi-public to public open space.

3.5. Streets, alleys and courtyards

Most of the semi-public open spaces and alleys are alwaysshaded. This offered the closely knit structures good protectionfrom direct solar radiation, which is substantial in the absence ofcloud cover, through mutual shading. The alleys between thebuildings are quite narrow (w900 mm) and are usually treated incow-dung (Fig. 8). The streets connecting the clusters in the oldersettlement are also narrow (w3e4.5 m). Major streets aredeveloped along the NWeSE direction following the naturalslope of the terrain. This allowed natural gravity flow in the openstreet sewers.

Interestingly, the cultural practice of sprinkling water in theopen spaces every morning also enhances the thermal comfort ofthe outdoors. Narrow streets also protect the semi outdoorspaces from hot breezes. In addition, they also trap the cool massof air within them. As it is a dry climate, enhanced air movementin summer, only causes physiological discomfort and convectiveheat gain.

Small internal courtyards are found in a few large dwellings.Their size is very small compared to the building height,providing ample diffused daylight into the interior. These areused primarily for outdoor activities like scullery, sitting, clean-ing pulses, fish-net repair, yarn dyeing, timber craft, etc.,requiring shaded work space with ample daylight. Therefore,these are mostly found in fishermen’s, weaver’s and carpenter’shouses. These spaces are also used for drying of pulses, clothesand storage of water. Trees or other plant material is seldomfound in these internal courtyards, and are often paved in stoneto accommodate the activities mentioned above.

3.6. Construction methods and materials

Hard building stone like granite (k-value¼ 2.92 W/m K) slate(k-value¼ 1.53 W/mK), hard bricks (k-value¼ 1.47 W/mK) andtimber are available aplenty in and around the settlement. Asa result, locally available materials and construction methods areused in all the buildings. However, due to the migration of‘Vaddera’ the local stone cutter community, stone walls and roofsare being replaced by brick and tiles/concrete for the last 10years. Lime and mud are used as binding material in stone and

Fig. 6. Typical large cluster formed out of the enclosed courtyard houses/clusters occupied by Brahmins off the Bazaar Street.

M. Indraganti / Building and Environment 45 (2010) 2709e2722 2715

brick masonry. In the recent years cement is mostly used. Mudmixed with some local water proofing admixtures (jaggery andkarakkai, a small nut) is also used extensively in walls, roofs andfor flooring as well.

Most of the houses are single storied constructions with anoblong built form having an aspect ratio of 1:1.5 or more and tiledroofs with gentle slope. Interesting, all the houses have low plinths(200e400 mm), to offer protection from the hot breezes blowingfrom the hot exterior and bright daylight (Fig. 8B) in addition tolimit the heat gain. Assumable, protection from rain water pene-tration was not found to be important, as the rainfall is low and thestreet/sewers are laid along the slope of the terrain. Interesting,the roofs do not feature any eaves gutters to collect rainwater fromthe roofs.

3.6.1. Walls and roofsThe requirement of high thermal mass to maintain higher time

lag to provide capacitative insulation was well understood by thelocal builders. Therefore, the walls and roofs are very thick, mostlyin stone, brick or in mud and slates or tiles respectively.

Houses of the well-to-do are in dressed stone masonry(450e600 mm thick) while the houses of the middle class are builtin brick/mud walls, sometimes reinforced with reed (Fig. 11). Thewalls in the houses of the poorer communities and temporaryenclosures for bathing are sometimes built in reed. Stone is alsoused in the bottom courses (up to about 600 mm high) or in the

entire ground floor while brick/mud is used in the upper part of thewall or in the upper floor. Although the sub soil is hard, this practiceoffered extra protection from subsidence.

Mud walls are usually built in courses 450 mm high. Local mudis thoroughly mixed with water and straw, kneaded and is usuallyreinforced with reeds. Granite posts (100�100 mm) are also usedin between (at 1500 mm c/c), for lateral strengthening of the wall.Mud walls are usually finished fine and are typically whitewashed.

Stone lintels (slate) over the ventilators, windows and doors areusually provided. The sunshades are either very small or arecompletely avoided sometimes. On the other hand, a small tin sheetawing is fixed to the wall to cover the window, or alternately, theslate lintel extended a little beyond the wall forming a sunshade.Most of the doors have sunshades in tiles with mud infill fixed toa wooden bracket, which are sometimes decorated. Provision ofwider sunshades to openings is not found necessary as (1) thewindow sill height is high, (2) shading is provided by the buildingopposite (3) thewindows are very small fixed to thickwalls, leavingdeep reveals (4) and the rainfall is low.

Mezzanine floors in large dwellings are built as wooden joistedfloors and are usually boarded in local timber. Upper floors in largehouses are built in ‘Madras Terrace’ (flat terracotta tile and limeflooring over wooden joisted floor). The timber for joists variedfrom fine teak wood to local country wood. Staircases are usually instone/brick masonry.

Fig. 7. Fishermen’s cluster formed by a veranda house, single and double roomed tenements. Smaller enclosed semi-private open spaces spilling into much larger central courtforming a hierarchy of open spaces.

M. Indraganti / Building and Environment 45 (2010) 2709e27222716

The wall interiors are mostly plastered in mortar (mud/lime)and are lime washed. This improved the internally reflectedcomponent of the room giving soft tonal differences of light inthe interior. The upper floors usually have very few internal

Fig. 8. Hierarchy of networks. (A) Major village arterial road. (B) Partially shaded sub-arteriadwellings and clusters.

partition walls, which are either in mud or brick. Ground floorsare usually covered in rough finished slate slabs, as slate iseasily procured from quarries nearby (for example: quarry atShahbad).

l roads passing through/joining the clusters. (C) Fully shaded narrow alleys connecting

Fig. 9. Wall construction. (A) Double storied house ‘gadde’ built in stone with very few openings. (B) Mud wall construction in tiers of 450 mm height. (C) Brick walls in mud mortarwith alternating stretcher and header courses and brick on edge course at the top and bottom of the wall adding lateral resistance. (D) Courses of stone masonry at the bottom of thebrick wall in mud mortar. (E) Remnants of the fort wall (900 mm thick) in mud mortar. (F) Lime plastered stone walled house, white washed.

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The roofs are most often single pitched (slope <30�), supportedon wooden trusses and rafters. The gable walls are plain and oftenhave a small ventilator near the ridge. Many varieties of localtimbers are used for roof trusses, which are built by the localcarpenter community. Thick stone wall-plates received the rooftrusses, which are often supported on the courses of ‘brick on edge’(Fig. 9c). These ‘brick on edge’ courses, through spring action,provided resistance against lateral thrust, often found in wallssupporting the sloped roofs. They are also provided at the bottom ofthe walls for a similar function.

In order to increase the heat capacity of the roof, tiled roofs arealways provided with mud in fills (w200 mm thick) laid over reedmatting, which is fixed to the wooden purlins (Fig. 12A and B). In

Fig. 10. (A) View of the roof. (B) Sectional details of the roof: (1) overlapping pot tiles laid toforming the soffit, (4) tie beam of the country wood roofing truss, (5) stone wall plate at theused in the houses of the poor. (D, E) Small orifices/roof lights, in the flat roof to allow hotwood truss. (H) Madras Terrace in teak wood joists and boarding having a metal grilled sk

a fewhouses, overlapping layers of slate is also used for roofing. Stoneslabs are laid to a very gentle slope on wooden purlins and battens.

As the peak hourly rainfall is very low (w28e40 mm/h) and therainy days are very few (w15 days in the peak monsoon month),lower roof slopes are found to be giving adequate protection fromrain. The triangular space of the roof is sometimes used for storage,without any finely finished false ceiling. Therefore, higher volumeof air is available for circulation, while hot air is accumulated nearthe ceiling and exited from the ventilators provided at a muchhigher level than the occupant’s body level.

On the other hand, flat roofs often have small orifices andopenings (w600� 600 mm maximum) to facilitate hot air exit(Fig. 10 D,E, and H). These are found to be adaptively closed with

slope, (2) mud mortar infill, (3) reed mat batting on the battens fixed to wooden rafterssoffit of the eaves, (6) supporting brick/stone wall. (C) Reed and thatch wall and roofingair exit, often covered during the day. (F) Stone roof over wooden rafters. (G) Countryy light, used in the houses of the affluent. (I) Slate roofing over wooden roof trusses.

M. Indraganti / Building and Environment 45 (2010) 2709e27222718

a thick stone slab during the day when the outside is hotter thanthe interior in summer. As propounded by Nicol [15], passivebuildings need active participants to maintain comfortable condi-tions inside.

3.6.2. Openings, colour and textureThe nature of the openings in Marikal purely emanated from the

climatological requirement. Windows are either very small or arecompletely absent in some of the smaller houses. Small ventilatorshigh on the gable wall are provided instead (Fig. 11A). They provideexternally and internally reflected, diffused daylight to the interior.Themetal grills or RCC jalis fitted to the ventilators eliminatedmostof the bright externally reflected light.

The window size varied from 0.09 to 0.54 m2. This offeredimmense protection from the radiant heat gain, hot air drafts, andpainful glare. Thus, most of the light in the indoors is soft internallyreflected and diffused light.

The deep reveals of the windows are splayed as shown inFig. 11C, to provide contrast grading [[11], pp. 145]. This eliminatesstrong luminance contrast between the view and the windowsurround. In addition, splayed sills also reflect the light rays to thewall opposite, adding richly to the internally reflected component.It is important to note that the soffits of the ceilings are retained inthe natural colour of timber and are not painted white. Sometimesthey are very dark owing to greying of timber.

The fundamental function of a window is to provide naturalventilation, light and views depending on the activity being per-formed inside the room. Most of the dwelling units in Marikal areused for storage, cooking and sleeping. Sometimes the occupants alsocooked in the open yard outside the house. As a result, the activitiesrequiring ample daylight take place in the shaded part of the exterior,for example: on the gatchu (a sitting platform) outside the house.

Fascinating, some of the interior rooms (kitchens and sleepingrooms) are also provided with operable sky-lights for higher illumi-nation.Theseare closedwitha stoneslabadaptivelyby theoccupants,during the overheated part of the day (Figs. 10D, E, and H and 11D).

Heavy double leaved wooden ledged battened doors(1050� 2100 mm or smaller) with decorated jambs are usuallyused as main entrance doors in Marikal. These are usually paintedin blue or green or ochre. Similar doors are also used in thecompound walls of the cluster enclosures as well (Fig. 11F).Interestingly, thick panels (25e35 mm thick) formed the doorshutters, protecting from convective heat gain. In the shop houses,

Fig. 11. Details of openings: (A) Very small or no openings. (B) Small tin sheet awnings attbedroom. (E) Door details. (F) Compound wall door.

the door shutter leaves are of detachable type, to enable easymovement of customers and goods. Larger windows are mostoften fixed to the compound walls of the courtyards to facilitateair movement (Fig. 11).

The external and internal walls are all predominantly whitewashed. Importantly, the users have painted the street side wallswhite, while leaving the walls facing the narrower alleys unpaintedwhen high expenditure on painting is not permissible (Fig. 11A).Painting the walls white reduces the radiant heat gain significantly.To provide for the necessary visual relief, more so in the absence ofgreen plant material, the doors and windows are usually painted inbright colours. As the windows are very small, painting the inte-riors white, allowed good internal reflection and resulted in higherlevels of indoor illumination. Ceiling soffits are seldom treated andare left bare.

4. Typologies of houses

The dwelling units are analysed based on the aspects of layout,plan configuration, occupant’s sociological classification vis-à-visactivity, construction materials used, etc. The analysis is presentedin Table 1. Marikal has a highly evolved vernacular architecturalstyle in its plan form and structure, making use of the locallyavailable material and craftsmanship.

The house plans essentially varied in quality of detailing but notin fundamental functioning of the building. A single room house ofa lower class family gently transforms itself in to a six roombungalow of a Reddy or Lingayat family, without compromising onany of its basic functional or climatological essentials, like smallopenings, courtyards, lowplinths, thick shutters, shadedopen/semi-outdoor spaces, light wells/roof lights, etc. as shown in Table 1.

The plan form was found to be in great harmony with theoccupation/activities of the occupant. For example, the weaver’shouses are found to have a long hall (w15 m long), overlookingonto a small indoor court to accommodate the hand loom andweaving of two saris at once. This space is devoid of any externalopenings as they would permit dust. However, the indoor courtsmaintain the high illumination levels without sharp contrasts,necessary for precision weaving. Unfortunately, the weavers’community has migrated completely a few generations earlier, dueto the dwindling local patronage.

Houses of the upper caste families are two storied, largertenements facing the fort street. These have small internal courts

ached. (C) Splayed sill to the window and deep reveals. (D) Sky light to light kitchen/

Table 1Typologies of houses found in Marikal.

(continued on next page)

M. Indraganti / Building and Environment 45 (2010) 2709e2722 2719

Legends: L: Living; D e Dining; K e Kitchen; Ha e Hall; B e Bed room; ST e Store; SH e Shop; Toi: Ver e Verandah; Gatchu e Sitting Platform; Toilet e Toi; BA e Bath;Co e Open Court.

Table 2A comparative analysis of the thermal properties of traditional and modernwall and roof construction typical in Marikal, showing the traditional construction having superiorthermal properties than the latter.

Function Description of thecross section

Overallthickness(m)

Surface conductance Thermal properties of the layers U-value(W/m2 K)

Heatcapacity(kJ/m3 K)

Outdoor(W/m2 K)

Indoor(W/m2 K)

Layer-1 Layer-2 Layer-3

L (m) k-value(W/mK)

L (m) k-value(W/mK)

L (m) k-value(W/mK)

Brick wall(external)

0.230 m Thick brick wall with0.018 m thick external and0.012 m internal cement plaster

0.26 13.18 8.12 0.018 0.721 0.23 0.84 0.012 0.721 1.94 1360

Mud wall(external)

0.450 m Thick mud wall with0.025 m thick lime plaster onboth sides

0.45 7.78 8.12 0.025 0.73 0.45 1.25 0.025 0.73 1.47 2050

Externalmasonry wall

0.600 m Thick granite stonemasonry wall (unplastered)

0.6 7.78 8.12 e e 0.6 2.92 e e 2.19 2132

Concrete roof 0.2 m Thick concrete roof with0.012 m thick soffit plaster

0.212 22.7 9.48 e e 0.2 1.274 0.012 0.721 3.09 168

Tiled roof 0.01 m Thick tile roof 0.25 mthick over mud infill, laid over0.006 m thick bamboo/reedmatting

0.266 22.7 9.48 0.01 0.84 0.25 1.25 0.006 0.14 2.47 2050

Slate roof Two layers of 0.012 m thickoverlapping slate stone slabswith 0.008 m thick cavity

0.024 22.7 9.48 0.012 1.53 0.008 0.026 0.012 1.53 2.11 2212.5

U e value¼ overall transmittance of the section; k-value¼ thermal conductivity of the layer; L¼ thickness of the layer; traditional walls are considered sheltered, whilemodern walls are assumed to have normal exposure for estimating surface conductance; values in bold¼ traditional construction.

Table 1 (continued).

M. Indraganti / Building and Environment 45 (2010) 2709e27222720

Fig. 12. Climate responsive architecture getting transformed into concrete roofed light weight buildings irreverent to local climate and context.

M. Indraganti / Building and Environment 45 (2010) 2709e2722 2721

sometimes or roof lights to light the interior rooms. A small oblongcentral open terrace, flanked by two bed rooms on both the sides isthe most striking and important element of the upper floors. As thewidth is small, this space remains shaded most of the time and ismainly used for many outdoor activities and sleeping at night(Table 1). This court also features a small metal grilled roof light tolight the interior living areas in the lower floors.

On the other hand, houses of fishermen, potters, etc. (verandahhouses) have small covered verandahs which are primarily used formany activities requiring ample daylight, as explained in Section3.5. The shop houses on the fort area have large doors and shadedverandahs to accommodate the selling activity.

5. Behavioural adaptation

User’s behavioural adaptation is found to be essential forachieving thermal comfort in passive buildings [16]. The author hasobserved several behavioural adaptive actions the occupants haveunder taken in her many field study visits throughout the year.Important adaptation methods observed are ‘clothing adaptation,moving to a shaded outdoor area during the period of discomfort,closing the roof lights/windows/doors, staying away from hot areas,and adaptively synchronizing the activities with the spatial environ-mental qualities’, etc. For example, the occupants have used well litsemi outdoor areas for jobs that require higher illumination. Theyare found to adaptively balance the activities with the environ-mental characteristicsof various spacesof thedwellingunit/outdoorareas. Similar observation is also made by Rijal and Yoshida [17].

In addition, special ‘Pandiri’ (a four pillared verandah) erected inthe front yard, temporarily using fresh green leaves during theweddings in summer is retained by the occupants even after theweddings. This ‘Pandiri’ formed a shaded vestibule in front of themain door, giving the necessary thermal relief in summer.

6. Present day scenario

The prototype houses mentioned in Table 1 are the outcome ofgenerations of evolutionary process and indigenous knowledgetransfer. These are designed to perform well even without the useof any electrical controls like ceiling fans, air conditioners andheaters. However, with the availability of electricity and ceilingfans, in the last few decades, the ‘house form’ of Marikal hasundergone rapid changes.

Large thermalmass of the houses is being given a go by, to enablefaster construction and to save space. The walls now are usually230 mm thick or slender brick walls in mud or cement mortar. Theroofs are either in RCC (150 mm thick), without any capacitative

insulation on the top, or galvanized iron sheets or asbestos sheets ifthe occupant cannot afford the former (Refer Table 2).

With the availability of ceiling fans, most of the activities, oncebeing performed in the semi-outdoors, like cleaning the grain,resting, reading, etc. in the traditional houses are now being per-formed indoors. As a result, the window sizes are becoming muchlarger allowing more light and radiation. Unfortunately, as Marikalis in the non-priority areas of Ranga Reddy district, electric poweravailability is limited (5e8 h/day), more so in summer. Much asexpected, people living in concrete roofed houses, express higherthermal discomfort.

Moreover, the villagers attach a tag of higher social status andmodernity to a concrete roof house (locally called “Chatt illu”) thanto a tiled vernacular house, influenced by many an imported urbanimagery. Surprisingly, boys having concrete roofed houses are givenhigher priority in marriages too.

As a consequence, the local prototypes are getting replaced bya modern architectural idiom, relying on the use of electricalcontrols for comfort. The cozy clusters at human scale are gettingmetamorphosed into isolated villas as shown in Fig. 12. Once highlyclimate sensitive architecture and behavioural patterns are slowlygetting transformed into architecture and attitudes that are irrev-erent to climate and customs. Similar concern is expressed byUpadhyay et al. [18] and Hanaoka et al. [19]. Due to the reducedpatronage, the local roofing craft is at the verge of extinction. Thelocal potter community is now job-shifting tomake other objects ofhigher commercial value. As a result, a dwindling ‘supply-demand’relationship is observed. Providing thermal comfort, the primaryfunction of our third skin (the building) is thus found to bediminishing, as buildings become lighter.

As we seek a fine balance between modernization and tradi-tional values, the success of traditional settlements holds valuablelessons for urban designers, architects and administrators. Conti-nuity of tradition needs planning, design regulations and guidelinesas well as the establishment of a code of practice to govern andcontrol the proper implications of immutables, regardless ofwhether the technology is newor traditional [2]. Only then the newarchitecture we produce remains deeply rooted in local climate,context and customs.

7. Conclusions

Architecture and climate form an inseparable bond in anytraditional shelter form. Learning them in detail helps designersplan sustainable settlements in future, especially in the wake ofthe present energy debate. The vernacular settlement of Marikal,in the composite climatic zone in Ranga Reddy district of AndhraPradesh has been studied and documented as part of a large

M. Indraganti / Building and Environment 45 (2010) 2709e27222722

development study. The data has been analysed keeping in mindthe aspects of architectural typology and the climate appropri-ateness of various features of the building and the settlement.Following are the conclusions:

1. The architecture of Marikal is found to be highly climatesensitive, reflecting a set of varying physical and nonphysicaldeterminant forces such as climate and geology, religion, socialvalues, economics, technology and administrative factors, alllinked to one another.

2. The settlement and buildings in Marikal are designed keepingin mind the hot-arid summer season. Marikal has evolved asa natural settlement at the bottom of a shallow trough formedby the local topography. This ensures adequate ground waterlevel and protection from the hot breezes during droughts andhot summers.

3. Small dense clusters of small and compact tenementsconfigured organically along the narrow streets and alleysform a major part of the settlement, shielding the buildingwalls and ground from direct solar radiation and intensediscomfort glare.

4. The building fabric is very thick, with high thermal mass (Table2). It has thick white walls, heavy roofs and small windows,incorporating locally available methods and materials likestone, brick, mud and wood.

5. Many house typologies are identified. The house plans essen-tially vary in size, shape and quality of detailing, but not in theirclimate sensitivity. They are in great harmony with the occu-pation/activities of the occupant. The occupants adaptivelysynchronize their activities with the spatial environmentalqualities of the space.

6. However, for the last few decades, the built form, architectureand people’s attitudes in Marikal are undergoing a visibletransformation owing to socio-economic influences and theavailability of electric controls for comfort. In addition, villagersassociate higher social value to concrete houses due to theimported urban imagery and consider them aspirational,despite experiencing higher thermal discomfort in them.

7. Once highly climate appropriate architecture and behaviouralpatterns in Marikal are slowly getting metamorphosed intoarchitecture and attitudes that are irreverent to climate andcontext.

Acknowledgements

This work was facilitated by a grant from American TeluguAssociation, Naperville, Illinois and Telugu Society of America Inc.through a sponsorship from Murali S Chanduri and Swarna SChanduri, Claremont, California, at the request of SKCV Children’sTrust, Vijayawada. I sincerely thank the sponsors and JandhyalaShankar of SKCVC for the support.

I am grateful to Krishnachari, Narasimha Reddy and all thevillagers of Marikal for their cooperation. I would like to thankBobby Karlapudy and Wilson for their support in exploratory andPhysical land surveys and my students, Ashwin, Amol, Shravan,Vaahini, Raghu and others for their involvement in the docu-mentation and Ravi for his panoramic views. I would like tofondly acknowledge the help rendered by my daughters Lahari,Millie and husband Prasad VS Indraganti during the prolongedresearch.

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