Kancha classroom concept
School Mis primeras Letras (My first letters) Puembo / Ecuador

Puembo: location and origin of the project

Puembo is a small town located East of Quito, Ecuador. With a population of 18.000 inhabitants, Puembo’s economy was originally based on agriculture and stockbreeding, but recently shifted towards the industrial flower production: as a result, greenhouses have flourished and dwellings have been built on former rural areas, soon becoming the suburb of Quito. The current population is a mix of people with farming and urban backgrounds.

The school ‘My first letters’ therefore welcomes children with mixed origins. It is a primary school with two levels made of 52 pupils aged 3 and 4. The 3 teachers are in charge of education as well as administrative duties. The school is also a meeting place for the people in charge of San Jose de Puembo.
The creation of a new class for 5-year old children would fulfil two major needs: on one hand, it would save parents from driving out of district using public transport or private cars. On the other hand, it would allow children to stay in the same place until they are 6.

Key words: Mutation, melting pot, urbanization.

Concept Kancha classroom and cross cultural housing

‘The childhood is the time of awareness of ourselves and discovery as unique entities ' Clare Cooper Marcus

The existing school building is made of classrooms aligned on a narrow strip of land, lacking in unity and identity. First we propose to design a room that could be an exact answer for the school and at the same time a prototype that could be adapted to the other schools of the region. Second, the architectural project would visually materialize the cross-cultural local environment, which is today invisible in the architectural and urban landscape. Third we want these two issues to be addressed in a sustainable project.

In that purpose we develop with the teachers a project of ' master classroom ', defining the school’s identity and unity. The project is actually a modern version of the original Quechuan concept of kanchas, meaning “surrounding walls”. The internal space made of intimate patios (images i 02), reminds us of Puembo’s former spatial organization (Puento in Quechua).

This master classroom enables a new level of circulation between spaces by defining the pedestrian entry on the East, and a North-South axis of communication with the other rooms. As an introduction to the public space, an interior street embodies the learning space and acts as a gallery or a scenario for the school cultural performances. The space in front of the classroom is a reinterpretation of the original countryside houses or haciendas (image i 01), which corridors were used as viewing points protected from bad weather.

Next to the classroom is a functional area dedicated to toilets compliant with the Ecuadorian regulation. This area could also be used as a warehouse or a cellar, with a ventilation and bioclimatic fonction.

Key words: Kancha Classroom, cross cultural architecture, envelope, gallery.

In situ-tech and sustainable poiesis

Geographic and bioclimatic context

Puembo (Lat. 0 ° 11 ' S Long. 78 ° 20 ' W) is located at more than 2500 m high, and offers a moderate sub-humid climate (with some semi-dry areas). The annual temperatures range from 10 to 23 ° C. The prevailing winds come from the North and the North-East (image i 03), rainfall 800 -1000 mm year.

We have chosen a project able to address 3 aspects of sustainability: first the enhanced use and recycling of local building techniques using natural materials with a low ecological impact and a high storage capacity of CO2. Second, the priority given to thermal comfort in the classrooms with a proper insulation and a natural ventilation system. Third, a simple and compact design enabling improved energetic performance and an implementation on par with the local know-how.

In situ-tech or loci-tech

This project is not about low or high-tech. We call it “in situ-tech”, i.e. an attempt to promote again the local sustainable construction techniques. Called Bahareque or Quincha, this method used in the Andean zone is a wet loam infill technique in skeleton structures combining optimal antiseismic and insulation properties. It is actually a mix of mud and tick cut straw (30 cm : l 0.1 W/m°C, thermal resistance 3.0 m ². ° C/W and a U coefficient of 0.33 W/m ². ° C). The use of wood as a local resource also involves recycling some by-products: for example, the school area is currently delimited by an unexpected wall of pallets donated by manufacturers. We are thinking of reusing the existing pallets (or future donations from the flower industry) to build the brise soleils: the project measurements are therefore based on the pallet standard size (1.20 x 1.00 m). The entire wood of a buiding could stock up to 15 tons of CO2.

School time and thermal comfort

Given Puembo's moderate temperatures and in order to ensure a 20°C thermal comfort, the classroom needs to be insulated from the excess of solar heating between 11 am and 1 pm (90 °) and to benefit from geothermal heating from 3 pm (also between 6 and 10 am). Beside the mud and straw walls, an insulated and sealed soil will be created with a light screed made of concrete and pumice stones (l: 0.2 W/m°C). There are plenty of this stones in the region and they can be collected manually. The major openings located in the western part of the complex would act as a thermal veranda; with a calorific storage coming from the screed (the complex would have a thermal resistance of 1.5 m ². ° C/W and a U coefficient of 0.67 W/m ². ° C). The same system would be used for the interior walls of the school as no heating system is currently used. To follow the local regulation on insulation, openings have been designed in the windows and the wood panels. The building location creates a natural barrier against the prevailing winds from the N and NE.

The roof is made of a galvanized iron sheet, the only material to keep energy, being easily available and of better quality than fibrocement. The roof has been separated from the classroom to create a permeable and ventilated vacuum. A higher structure has been added to work as a chimney or a draught for the toilets during high temperature period. The straw used for the walls will also protect the ceiling (25 cm thickness) and will undergo a lime plaster treatment to avoid rodents and water infiltration.

Another strong point of the renovation work is the reinjection of air inside the room, a crucial point for the health of the pupils: on the Western façade, a vegetal wall made of local plants will purify the air of VOC (the selection of plants is based on researches from Dr B.C. Wolverton).

This project is more than a technical or technological statement: it represents a global, cultural and even political approach in a continent where nature has always played a major role. It aims at creating (poiesis) a sustainable concept for countries like Ecuador by using nature not only as a raw material but also as a cosmological principle.

Key words: recycling of techniques and materials, natural Materials, sustainable poiesis.

Location