Background[edit | edit source]
The building of schools is a significant area of construction activity in many developing countries. School building can be organised as government or donor-supported programmes, or by NGOs and communities, and sometimes by parents themselves. In the former case the programme might comprise hundreds or even thousands of schools, while in the latter case there could be just one school to build, or usually a small number. Local authorities are sometimes also involved in the building of schools, usually in urban areas.
Schools can be considered as primary - catering for pupils up to the age of 10, 11 or 12, or secondary - for pupils within an age range of 10 to 19. Additionally there can be vocational training centres - generally for youths above about 14 years of age and sometimes also for adults, and in some cases schools can also function as community and meeting places, or be used for some form of adult learning, for example in literacy. Some rural schools, to which pupils have to travel considerable distances, can also have dormitories.
As well as the scale of a school construction project and the age range or function to which a school would be put being some significant factors to consider in the design and building of particular school buildings, there are also numerous other important factors including climatic conditions, disaster risk, cultural issues, available building materials and skills, terrain, ICTs and facilities for displays and demonstrations, and health and safety. Because the nature of some of these factors would vary from place to place it is not possible to define an ideal or optimum school building suitable for everywhere. Instead it is proposed in this brief to consider some issues, principles and case studies or examples to act as a guide for the development of a model for a particular location.
A school building can have a significant positive or negative effect towards fostering a productive learning environment. Classrooms that are dark, uncomfortable, crowded, noisy or where the teacher is a long way or at times hidden from the pupils can be a disincentive for pupils to learn or even to wish to continue with their studies. Design of schools from the viewpoint of the user is important to ensure that all or most of their needs are met.
Some Important Issues or Principles[edit | edit source]
Space - Schools differ from most domestic buildings in that classrooms need to accommodate comfortably as many as 30, and sometimes 40, pupils together with space for a teacher and possibly for storage, displays and equipment. One recommendation is to allow 1.3 m2 of space per pupil and an additional two metres between the first row of pupils desks and one of the walls for the teacher's desk, board and space to move. With 30 pupils such a classroom could have dimensions of 7 x 7 metres (or another combination of length and width giving the same overall area), amounting to nearly 50 m2 in area. It is in any case not recommended to have a classroom with an area of less than 40 m2, unless it is known that there will never be more than 20 pupils in the room.
A basic one or two classroom rural primary school would also require a private room or office for the teacher or teachers and a room for storage of materials and equipment. Rooms of about 10 m2 each would accommodate one or two teachers' own area and a room for storage. Additionally, if the school would also be used as a community meeting centre, one of the classrooms would need to be considerably larger than 40 m2, say 80 m2 to accommodate about 100 people either standing or seated in rows.
Secondary schools and vocational training centres would generally be considerably larger than primary schools and generally have at least several classrooms. Because pupils would be finishing lessons at more or less the same time, circulation of pupils and teachers would need to be considered. Larger schools can have classrooms positioned around a corridor or courtyard to facilitate circulation. Secondary schools, and larger primary schools, could need additional facilities, including a library, rooms for practical classes and workshops, an assembly hall, a head teacher's office and general office, changing or locker rooms and wardrobes, a sick room and possibly a dining room and dormitory.
A porch or verandah can be a particularly valuable addition to school to provide shading to the classrooms in hot weather and could also form an addition to the teaching, storage, meeting or display space.
Because classrooms and other rooms in schools are generally considerably larger than rooms in houses, this presents more of a challenge in the design and construction of the roof compared with housing. Although the same types of roof can generally be used as for housing, the larger scale and greater complexity of the roofs of school buildings can make the building of a school per unit area considerably greater than for a house. Additionally structural columns within rooms are generally not used in order not to restrict visibility. Roofs for school buildings are considered in more detail in a subsequent section.
Siting - A level site is more suitable than a sloping one as with a sloping site considerably more ground clearance would be required to ensure that the floors of the classrooms are reasonably level. Also the design of the school on sloping ground would also be more complex with possibly the need to connect rooms by ramps or stairs. The site chosen would need to be well drained and not subject to flooding or the risk that debris is brought down into the school grounds after heavy rains. Tall trees can provide useful shading in hot weather, but if the area is at risk from very high winds and storms then it would be better to site the school away from trees which can fall or shed branches. For young children a busy main road nearby can be a hazard, as can a river, pond or well. A fence around the school grounds can be useful to keep animals out or to discourage young children from wandering off.
Cost - Reducing costs can be a high priority in building schools as, if this is a community project, community members who might be relatively poor, would want to keep the contributions they make to building the school to a level they can afford, and in government or donor funded programmes reducing the cost per school can enable more schools to be built. However, it is important to take into consideration not just the cost of building the school itself, but also the cost of maintaining it over its entire period of use. A cheaply built school could turn out to be a false bargain if subsequently there are defects to be put right, materials and components need to be replaced after a relatively short time, and there is a continuous need to undertake repairs and rehabilitation. A school should also not be built so cheaply that it produces discomfort for the users, for example with too few openings or windows that the rooms are too dark, or built with very light materials that heat up quickly in the hot weather and make it uncomfortably hot in the classrooms, or with a flimsy roof that lets in water when it rains.
Community Participation - Engaging local people, especially parents, in dialogue about the layout and facilities at the proposed school is important for the school to meet the needs of the local community and be looked after and cared for. In some cases local people might also be interested to contribute towards the cost of additional facilities if these were to be provided. For practical and cost reasons it might not always be possible to build and equip a school in exactly the way local people would like, in which case a compromise would need to be reached, but at least it is important to discuss the school with local people. One decision to consider is whether the school will only be used for the education of children or whether there would also be facilities for the community to meet and, possibly, also a resource centre for facilitating local development needs. Local people can also offer more practical help such as undertaking of some of the building work. However, if they agree to do this, such help has not to be taken for granted and some form of modest payment or the offer of some additional facilities for the school might need to be provided. When the school building is completed the occasion can be marked by some sort of cultural event to which all local people are invited. If the school is then handed over to the local community some arrangements would need to have been made for upkeep and maintenance. Even if the school building is the responsibility of an NGO, local authority or government education department, the local community can still make some contribution towards the running and upkeep of the school.
Lighting - Many rural schools rely on natural lighting for illumination in the classrooms as the schools are either not connected to electricity supplies, or the use of electricity for lighting is expensive and this would significantly add to the cost of running the schools. Glass is sometimes used in the windows, but this adds a considerable expense and if the hot sun shines directly through the glass this can make the classrooms very hot. With windows that can be swung open to let in ventilation, this can present an accident risk to young children, and safer options for windows that can be opened fully are more expensive. A cheaper option is to use no glass but to have wooden or metal shutters that are closed when the school is empty or when it is raining heavily. If the shutters are closed due to rain then it would be too dark to read or write in the class, so either artificial lighting would need to be provided, or the school closed for the day when a storm is due. In India and some other countries brick jallis have been used to create opening to let in light and ventilation in the wall. Because the opening between the bricks are relatively small in size they would be effective for excluding water from rain except when it is very heavy and driven onto the wall by a strong wind.
Recommended minimum illumination levels in schools are 130 lux in general classrooms and offices, 200 lux in laboratories and 300 lux in areas used for drawing, crafts and sewing. While it would rarely be possible to have access to a light meter to check on these light levels it can be assumed that in a normal sized classroom it would need at least two, and preferably three, window openings of at least 1500 x 1200 mm, or openings of other sizes with equivalent area, to achieve the 130 lux level in tropical areas for sunny or lightly overcast conditions. It is better, for more even illumination, for the classroom to have two or more external walls each with a window, rather than having all the windows in one of the walls. Long narrow rooms with openings at only one end, which in any case are less practicable as functioning classrooms, would need a greater area of openings than suggested above as light levels would fall off noticeably at the far end of the room. Jalis, such as that shown above would need about 1½ more area of openings in total than for conventional windows as a part of the opening in a jali is effectively cut off from admitting light. It is preferable to arrange the classroom to avoid the teacher or pupils having to face the sun directly, or reflected and causing glare from some surfaces such as boards.
Services and Infrastructure - When funds for school building are very limited there can be an inclination not to provide a dedicated water supply and sanitation services, but such provision is very important and could only be omitted in exceptional circumstances, e.g. if it intended to provided services at a later, but not very far-off, date. Nevertheless there are still numerous schools throughout the world, generally very small schools in rural areas, without dedicated water and sanitation provision. If public water supplies and latrines are located close to a school then this situation is acceptable. If not, then high priority needs to be given to installing these facilities within the school grounds or close by.
If water reticulation is available then this would need to be extended to the school and a water tap provided. If this is not available nearby than consideration would need to be given to sinking a well or, preferably, a borehole at or near the school. A well is sometimes preferred for water supply in remote rural areas because it can be dug out by hand, whereas a borehole needs to be drilled out mechanically and an engineer with a drill would need to be hired for this. However, if a well is used it would still be preferable to have the top covered and a suitable manual pump inserted, rather than having an open well and using some form of winch and bucket, where there is a risk that, particularly, young children can fall in. Shallow wells or ponds would rarely be suitable as they would be likely to become dry when there is no rain, and the water can more easily become contaminated by human and animal wastes.
Advantage can also be taken of the greater roof area of school buildings compared with domestic buildings, but only if the roof is sloping, to collect rainwater. Guttering and a rainwater collection tank would not add greatly to the cost of a school but would provide the significant benefit of allowing the demand for water from school pupils to be partially met. The collected water from the tank would be suitable for washing, but a simple sand filter would need to be used if the water would also be use for drinking. For further information on collecting water from roof run-offs see the Well Fact sheet on Domestic Rainwater Harvesting although dealing with domestic situations, they could also be applied to schools. Safe access to a latrine or, more likely in urban areas, a flush toilet, is essential for a school to function effectively. If children are unable to relieve themselves during school time they would be likely to be poorer learners, and if they do so behind vegetation, they would be more likely to be attacked by insects and animals, or be at risk of getting diseases and infections. Girls, whose education is in any case is often curtailed in favour of boys, would be particularly disadvantaged if no latrines or toilets were available, as they would prefer to be better concealed than boys when relieving themselves so that they would go further away putting themselves at greater risk or be prepared to put up with greater discomfort than boys to the disadvantage of their education.
To avoid unpleasant smells it would probably be best to site a latrine at least 30 metres away from the school building, and downwind of the prevailing wind. The latrine needs to be properly constructed and a proven design such as the Ventilated Improved Pit Latrine (VIP) developed by the Blair Research Institute in Zimbabwe used to avoid smells and diseases, and flies and other insects getting into the latrine. If there is rock below ground, or if there is a high water table the traditional latrine pit - which goes down several metres into the ground, might not be suitable, so the latrine would need to be built above ground, for example as a concrete box type chamber. This option could, however, be more costly than the conventional below ground latrine.
Further information on water and sanitation for schools and in general can be found here - for the WELL Fact Sheet on School Sanitation and Hygiene Education; and technical briefs produced by WELL on specific topics, click here.
An electricity supply for schools is becoming increasingly important, especially for secondary schools, even in rural areas, with the increasing use of computers and audio-visual media in schools. A separate dedicated power supply from an oil-fired generator would usually be an expensive option, so an important consideration in the siting of a secondary or even a large primary school would be on whether it can be connected easily to the electricity grid. If this is not possible and a generator too expensive, some other options could be possible, but each one by themselves would be unlikely to meet all the electricity requirements for a school. These options would include the use of solar power for computers and radios, the solar lantern for lighting, paraffin or kerosene lamps for lighting - although increasing risk of fire and possibly poisoning, and use of biogas for lighting, although again not an especially safe option.
Except for cases where the school serves a very localised area and children can go home for meals, it is likely that a meal would need to be provided at some time during the school day. In small schools, this could be done simply under some form of gazebo structure where the cooking would be done. The open sides of this structure would allow the smoke from cooking to escape. If cooking is carried out indoors it would be important to ensure that an adequate flue is installed and maintained to allow smoke to be removed. Larger schools and colleges would need a dedicated institutional kitchen to be included in the school design. Another Technical Brief from Practical Action's Technical Enquiry Service provides further details on stoves for institutional and commercial kitchens.
In high mountain areas or in developing regions in the far North or South, space heating would be a necessity for all or part of the year. For this purpose various types of stoves to burn oil or wood / biomass are available on the market. However, in cold climates the availability of wood or other biomass for fuel could be very limited. Larger buildings would need a dedicated oil, coal, wood or biomass or waste briquette fired boiler and a hot water distribution system to heat radiators.
Building Materials - A wide range of building material options can be used for low cost school construction. The main factor in the choice would depend on what is locally available or produced in the area and the relative cost of the materials available locally. Cost and availability of materials varies from place to place, so what is cheap and available in one area might not be so in another. Climate is another important factor determining material choice and building design. Whereas, for example, the use of earthen-based flat roofs as well as earth-based arches, vaults and domes would be completely suitable for relatively dry climates, these constructions would be less suitable in wetter climates unless they would be built and finished by highly skilled labour. It also needs to be noted that in areas with night frosts, or with very high daytime temperatures, a more massive type of construction would be better for reducing the effect of temperature change as a more heavy building heats up and cools down slower than a light one. This would imply the use of more massive materials such as rammed earth, stabilised earth blocks, or ashlar stone or rubble for walls and clay or concrete tiles or thatch for roofs, rather than a lightweight walling materials such as ferrocement or timber panels, or galvanised corrugated iron sheets for roofs. Although researchers and designers have sometimes devised innovative designs and use of materials for building, generally to reduce costs, make more use of waste materials, or to make more efficient use of space, there would also be greater risks with aiming to use particularly innovative or experimental materials and techniques. It would generally usually be better to choose materials which have already been well proven, and particularly if they are also well known about and used in the local area. Some relatively common materials used for construction are described briefly below, though they would not all be suitable for use in every case.
Walls[edit | edit source]
- Stone - rough hewn (rubble) or worked smooth (ashlar) blocks; the former being cheaper to produce while much less mortar is needed with the latter if they are well-finished • Stabilised soil blocks - now a proven low cost technology, especially in areas where soil of low shrinkage - which requires less use of costly stabiliser, is available locally • Rammed earth or pisé - a low cost material, though stabiliser might need to be added to control cracking, but labour-intensive and heavy to work with. The earth wall is built up between shutters or formwork that are progressively moved up the wall as construction proceeds. Use of internal and external plastering preferred with rammed earth buildings to reduce the need for maintenance, which is otherwise high, and the harbouring of insects and other pests.
- Fired clay bricks - requires a higher level of skill for laying than the larger blocks, also in some cases field bricks might be warped and of variable size, so relatively large quantities of mortar are required
- Concrete blocks - usually hollow rather than completely solid blocks are used as this allows some saving on the material for the blockmaker with the same level of structural
- stability as solid blocks. Blocks can be used structural or loadbearing, or used for infill. The strength and durability requirements of blocks for structural use need to be considerably higher than those for infill
- Precast concrete panels - panels are inserted within a structural frame and bolted with each other and the frame. Panels contain steel reinforcement, which increases the cost. However costs can be reduced by mass fabrication, so the application of pre-fabrication would be likely to be most relevant to very large building programmes with many identical or modular constructions. Prefabricated components do not require high levels of skill to erect, and erection can be relatively fast so having a low labour requirement - rarely a priority in many developing countries.
- Ferrocement - generally made by covering a steel wire-based mesh or framework on either side with cement mortar. Costs are saved by using chicken wire rather than more conventional steel reinforcement, and the walls of low rise buildings can be quite thin - only a few centimetres across. Ferrocement buildings also require labour-intensive construction, and the construction techniques are not difficult to learn. However, many do not like the appearance of ferrocement buildings and they certainly look quite different from conventional constructions. They also heat up and cool down quickly with changing temperature, and there are some doubts about their long-term durability in places where severe climate can be experienced.
- Timber and bamboo - can be used where this is plentiful supply. Strong bamboo species are a particularly versatile low cost construction material. However, bamboo and many timber species decay relatively quickly in the climates where they are found unless they are treated with preservatives, and there are no completely safe preservatives, though some are less hazardous than others. Also, some preservatives have limited effect on termites and other wood-boring insects, against which special and more costly precautions need to be taken.
Rooves[edit | edit source]
Note that the options for good roof construction materials are generally more limited than for wall construction materials, and the materials that offer better performance are generally higher in cost.
- Grass, reed or palm leaf thatch - a low cost option in rural areas, though it needs to be noted that good thatching material is getting in short supply in some places. However, despite its low cost thatch is generally an inferior roofing material as it can harbour insects and other pests, can be a fire risk, needs to be made up skilfully to offer reasonable performance, and deteriorates rapidly in a tropical climate due to the effects of weather and insect attack. If the roof needs to be renewed every few years than a thatch can prove to be a false economy, despite its low initial cost, compared to other roofing materials. A reasonable ceiling below the thatch roof can significantly improve safety and the learning environment, but would add to the cost. • Galvanised corrugated iron - this is widely used as a low cost roofing material in developing countries, particularly in Africa. However, this material has a number of limitations including that in humid conditions it corrodes and might have a lifetime of only 5 - 10 years. Also, it has rapid heat gain, so the indoor space underneath can become uncomfortably hot quite quickly during the day, and heavy rain on the roof is very noisy, making it difficult for children to hear each other and the teacher. With the thickest gauge of sheets, or ones that are specially coated, these problems would not be so great but their costs would be very much greater than for the standard sheets. Again a ceiling would produce significant improvements, especially in giving better acoustics.
- Asbestos cement - the use of corrugated asbestos cement sheets in buildings has been banned in most Western countries, due to the lung cancer risk from asbestos, but these sheets continue to be produced and used for building in some developing countries. Although the risk from asbestos cement is primarily to fabricators and builders using this material, rather than building users, as children's health is involved it is strongly advised not to use asbestos cements boards and sheets in school buildings. In some Western countries safer alternative cement-based boards and sheets are produced, generally based on using cellulose fibre for reinforcement. However, it is not known whether any of these materials are yet produced in developing countries.
- Micro concrete roofing (MCR) tiles - MCR technology is now well-established in a number of countries and small complete production plants can be bought for as little as £1000, so for a programme building a number of schools in an area it could be practicable to obtain such a plant to produce tiles for all the schools. MCR tiles and semi-sheets are relatively durable if well made and offer some protection from thermal gain and the noise of heavy rain or hail falling on the roof. Compared with some other materials such as galvanised corrugated iron the roof is heavier, so a more complicated and expensive roof structure is required, and the installation of the tiles is more complicated so a level of skill is required. These additional costs, however, can be offset against the greater durability of MCR tiles.
- Fired clay tiles - the use of these tiles is now somewhat limited and generally confined to areas where they are produced. Whereas a number of types of clay can be used for fired clay bricks, only a relatively few clay deposits have the necessary characteristics for the production of satisfactory fired tiles, so the availability of these tiles is by no means widespread. A number of shapes of clay tile have been produced. One of the most common is the rounded Bangalore type. Generally roofs of fired clay tiles are even heavier than for MCR, so there is the added cost of the roof structure to consider. Also, as clay tiles require a high-energy input to fire them they are not particularly environmentally benign, nor low in cost. Their main advantage, if well produced and properly installed on the roof is their high level of durability. A roof with these tiles would be good for 20, if not 50, years before the tiles need to be substantially replaced.
- Domes, vaults and corbelling of fired clay bricks or stabilised soil blocks - the use of these techniques offers the advantage that a roof structure is not required. However, the roof themselves would be heavy, so it would be important to ensure that the walls are strong enough to support these roof and additional strengthening, e.g. the use of a structural frame in the wall, might be required. The use of these techniques has most potential in areas where there is a tradition of building of domes, vaults and the use of corbelling. In other areas masons might be reluctant to use them and could need a lengthy period of trials and familiarisation. The use of domes, vaults and corbelling is generally best suited to relatively dry climates without significant night frosts, unless a protective external coating of render is applied, as the mortar joints between the bricks or blocks would be particularly exposed to rain and at risk of being damaged over the long term. Nevertheless these types of roofs are generally quite durable and domes have been found to be particularly effective against small to moderate earthquakes provided that they have been bonded well to the walls and the walls themselves have been strengthened so that they have not been bowed and crushed by the movement of the heavy dome during the quake.
- Earth or lime plaster-based flat roof - in some very dry areas there is a tradition of building flat roofs. The earth or plaster of the roof is supported on timber, or sometimes in newer buildings reinforced concrete, joists, which in turn support some form of reed or wire matting on which the earth or lime-based plaster is placed. However, even in relatively dry areas there can be heavy rain occasionally and after such spells the roofs would be likely to need extensive repair.
Precast concrete or ferrocement panels or channels - which are made sufficiently long to span the width of a roof section, for a small building, or to span between dividing walls or supporting beams for larger buildings. For precast concrete sections the cost of moulds, which need to be quite thick and heavy and accurately made, is a significant element of the total cost of the component. Ferrocement components are fabricated on formers of brick, concrete or hardwood, which are cheaper than fully made up concrete moulds. However, the making of ferrocement components in this way is much more labour intensive than the moulding of more conventional steel re-inforced panels or channels. Note also that use of precast components implies a high level of standardisation of components and relatively large-scale production, so would be most suitable for quite large-scale school building programmes, for which they would also offer some cost advantage compared with some other types of roofing options. The weak point of panel or channel construction is the mortar joint that would need to be put in between individual elements. This needs to be made to a good standards if it is not to crack and let in water. This type of construction is not really suitable in very wet areas as it would only be a matter of time before the mortar joints begin to leak, and putting a mastic or sealant material would be more expensive and not give much improvement as unless a very expensive option is chosen, this would deteriorate in high heat and exposure to sunlight. An example of the use of channel sections is shown below.
Maintenance - Undertaking a maintenance schedule is important for the school to remain a safe, healthy and comfortable place for learning. As noted above, some types of materials and construction details are more durable than others, however, all schools would require maintenance and inspection regularly. With any type of school building the fabric needs to be checked over thoroughly at least once a year, or after a serious wind or rain event. Small defects which are noticed, e.g. small cracks in plaster, missing tiles, small holes in walls or floors, or peeling of paint, would need to be repaired as soon as possible to avoid them getting worse. More serious defects, e.g. large cracks in walls, especially around openings, the falling down of significant sections of plaster or ceiling, roofs which leak regularly, doors, windows or shutters which can no longer be closed properly, and infestation of pests, could need a more thorough investigation by an expert and, possibly, quite extensive remedial action. It is useful to keep a written record of the inspections and maintenance that were carried out, what defects were found and what action was taken on them. If repairs are needed, a procedure also needs to be in place for paying the cost of the repairs, whether this is charged to a government department, local authority, NGO or to the parents themselves.
Practical Action The Schumacher Centre for Technology and Development Bourton-on-Dunsmore Rugby Warwickshire CV23 9QZ United Kingdom
Tel: +44 (0)1926 634400 Fax: +44 (0)1926 634401