Housing - Building Materials in Uganda
Housing - Building Materials Uganda
- Existing low cost housing projects in Uganda
- BeadforLife Housing Program for Women
- UN-Habitat –Mpumudde Housing Project
- Namuwongo Slum Upgrading Project
- Masese Women Housing Project
The past twenty years have seen a boom in the construction industry. Beginning with the liberalization of the economy in 1990, many foreign and local investors have selectively entered key sector industries. Investment in the building and construction sector is governed by a number of laws and regulations including the Building Code, Condominium Properties Act, National Shelter Strategy and the National Housing Policy. The government of Uganda is currently in the process of passing other laws and policies to consolidate building construction standards to increase competitiveness in the industry.
Specific incentives currently offered in the industry include a 20% initial allowance on the cost base of industrial and commercial buildings in the first year of use; a 5% industrial building allowance on cost of assets; a Withholding Tax exemption on the supply of plant and machinery; a VAT exemption for road construction; and a 0% Import duty on Paint and Machinery.
There are several actors in the construction sector in Uganda. These include; government institutions, parastatal bodies, non-governmental organizations, community based organizations, local councils, opinion leaders, private developers, contractors, women’s groups, technical schools and consulting firm. While the actors are many, their activities are not well synchronized as the sector is poorly organized. These actors operate through the following institutions; government ministries, Architects Registration Board (ARB), Contracts Committee (CC), Central Government (CG), District Local Government, Engineers Registration Board, Federation of Ugandan Consultants Organization (FUCO), Institution of Surveyors of Uganda (ISU), Kampala City Council Authority (KCCA), Local Government (LG), Public Private Partnerships (PPP), Surveyors Registration Board (SRB), Uganda Association for Consulting Engineers UACE), Uganda Bureau of Statistics (UBOS), Uganda Institute of Professional Engineers (UIPE), National Association of Building and Civil Engineering (UNABCEC), Uganda National Bureau of Standards (UNBS) and the Uganda Society of Architects(USA).
Materials used for wall construction
Materials commonly used for house building in Uganda include stones, cement, sand, un-burnt bricks, mud blocks, mud and wattle, adobe and timber. Other materials such as mass concrete and cement blocks are rarely used except in high class commercial/public buildings. In a few cases stabilized soil cement, lime bricks are used, especially in housing project schemes, but they are not widely accepted by individual developers because the technology is not yet embraced.
New technologies such as interlocking stabilized soil blocks (ISSB) have not been integrated into the educational curricula of secondary vocational institutions and tertiary engineering and architectural institutions and thus their adoption has been slow. Yet integrating new technology into the educational system is the most effective way of ensuring technology use in the future. At present one of the key challenges is changing the mentality of the companies and individuals already manufacturing and using the conventional of construction such as burned bricks and concrete blocks.
Materials used for roof construction
Iron sheeting is by far the most commonly used roofing material. Largely because of the costs, few developers can afford to use clay tiles on their dwellings. It is thus assumed that tiled houses are for the rich. Production of tiles in Uganda is mainly under the formal industries and as such their costs are beyond the reach of the majority of low and medium income households.
Also known as adobe, sun-dried bricks are widely used in Uganda. The bricks are not officially accepted for use in the urban environment because they are considered to be temporary, not standardized and vary widely in quality. Sun-dried bricks are produced and used by the informal sector mainly for low-cost housing. They are ideal in use in low cost housing and if proper guidance is given as to their use they can adequately contribute to alleviating the housing problem in the country. Whereas they are not popular in their current form they can be improved by stabilization, compression and standardization.
Local burnt bricks are currently the most commonly used material for single storey buildings, however material made from clay are gradually becoming scarce in Uganda due to the limited availability of appropriate clay in the country coupled with high demand associated with an enhanced construction sector.
A variety of timber species are available in Uganda including mahogany, mvule, pine, elgon, olive, nkoba, eucalyptus and many others. In the construction sector, timber is used for making roof trusses, shuttering, doors, windows and furniture and tools.
This is either hand crushed by local community members on a small scale or machine crushed on a wider commercial scale. Machine crushed stones are quite expensive and is often of high quality and of even dimension. Stones are used in various ways ranging from the construction of drainage channels to external cladding in house construction.
In Uganda the existing steel producing companies produce far below their installed capacity. There is heavy reliance on imported materials including steel roofing materials, iron sheets, cladding materials and fitting materials that make the construction industry vulnerable to global financial changes. This is also partly responsible for the high costs of housing in the country.
The types of materials available locally of course vary depending upon the conditions in the area of the building site.
In many areas, indigenous stone is available from the local region, such as limestone, marble, granite, and sandstone. It may be cut in quarries or removed from the surface of the ground (flag and fieldstone). Ideally, stone from the building site can be utilized. Depending on the stone type, it can be used for structural block, facing block, pavers, and crushed stone.
Most brick plants are located near the clay source they use to make brick. Bricks are molded and baked blocks of clay. Brick products come in many forms, including structural brick, face brick, roof tile, structural tile, paving brick, and floor tile.
Caliche is a soft limestone material which is mined from areas with calcium-carbonate soils and limestone bedrock. It is best known as a road bed material, but it can be processed into an unfired building block, stabilized with an additive such as cement. Other earth materials include soil blocks typically stabilized with a cement additive and produced with forms or compression.
Rammed earth consists of walls made from moist, sandy soil, or stabilized soil, which is tamped into form work. Walls are a minimum of 12? thick. The soil should contain about 30% clay and 70% sand.
The use of locally available and indigenous earth materials has several advantages in terms of sustainability. They:
• Reduce energy costs related to transportation.
• Reduce material costs due to reduced transportation costs, especially for well-established industries.
• Support local businesses and resource bases.
Both brick and stone materials are aesthetically pleasing, durable, and low maintenance. Exterior walls weather well, eliminating the need for constant refinishing and sealing. Interior use of brick and stone can also provide excellent thermal mass, or be used to provide radiant heat. Some stone and brick makes an ideal flooring or exterior paving material, remains cool in summer and possessing good thermal properties for passive solar heating. Caliches blocks have been produced for applications similar to stone and brick mentioned above. Caliches or earth material block have special structural and finishing characteristics.
Rammed earth is more often considered for use in walls, although it can also be used for floors. Rammed earth and Caliches blocks can be used for structural walls, and offer great potential as low-cost material alternatives with low embodied energy. In addition, such materials are fireproof.
Caliche blocks and rammed earth can be produced on-site. It is very important to have soils tested for construction material use. Some soils, such as highly expansive or bentonite soils are not suitable for structural use.
Soils for traditional adobe construction are not found in some areas, but other soils for earth building options are available. Many areas have a high percentage of soils suitable for ramming. Caliche is also abundant in many areas and is readily available locally.
Compressed earth brick technology
The advantages of compressed or rammed earth blocks are many. Since the blocks are machine made they are uniform in size and, with some care, uniform in density. It is common practice to dry stack (mortarless) or thicker walls immediately upon ejection from the machine since the blocks are smooth and sharp cornered. This saves on mortar costs as well as handling and damage costs as the blocks are only handled once.
All adobe press machines can be custom made to your specific requirements including: block sizes, power plants, regional parts replacement, dirt type, and additive needs.
Hollow interlocking blocks
A technology using reinforced hollow concrete block has been developed all over the world and long been in use. Its principle is to reinforce the masonry by grouting a concrete into the holes of the blocks with stands of steel rods at the critical locations (corners, ends, near openings, etc,). Horizontal reinforcements are also cast in blocks with a U shape. The technology using Hollow Interlocking Compressed Stabilized Earth Blocks (HI CSEB) is based on the same principle: to reinforce horizontally and vertically the masonry with Reinforce Cement Concrete (RCC) members. The advantage of hollow interlocking CSEB, compared to hollow concrete blocks, is that they offer keys, which interlock in the other blocks. Thus these walls offer more resistance to shear and buildings are stronger. They would better resist earthquakes without major damages. Compressed stabilized earth blocks have another advantage: they are in most cases cheaper and they are always more eco-friendly than concrete blocks.
Compressed Earth Blocks (CEB)
Compressed Earth Blocks are construction blocks made from a mixture of soil and a stabilizing agent compressed by different types of manual or motor-driven press machines. The Interlocking Stabilized Soil Blocks (ISSB) are a variation of stabilized mud blocks. These are dense solid blocks compacted using a machine with a mixture of soil, sand, stabilizer (cement/lime) and water. After 28 days curing, the stabilized mud blocks (SMB) are used for wall construction. Two block sizes (305 × 143 × 100 mm and 230 × 190 × 100 mm) have been standardized. These blocks are 2.5 to 2.8 times bigger in volume when compared with locally available conventional burnt clay bricks. Compressive strength of the block greatly depends upon the soil composition, density of the user. Major advantages of SMB are:
(a) energy efficient, do not require burning, 70% energy saving when compared to burnt bricks,
(b) economical, 20–40% savings in cost when compared to brick masonry,
(c) plastering can be eliminated, and
(d) better block finish and aesthetically pleasing appearance.
Fine concrete blocks
The concept and process is similar to the one employed for SMB production except that instead of soil, some fines are added to the mix. Fines like fly ash, polished stone waste, etc. are mixed with either sand or stone quarry dust, along with cement and water. The mixture is then compacted into blocks using a machine (manual or mechanized) and then cured for 28 days. Fines (like fly ash, polished stone waste, etc.) in the range of 20–25% by weight of sand can result in a good grading for the mixture and with 6–7% cement good quality block with wet strength. In addition to fines, about 10% red loamy soil addition can result in good natural mud colour for the block. The major advantage of fine concrete block is the utilization of waste products like fly ash, polished stone waste, mine wastes, etc. which otherwise cause pollution and environmental degradation.
Steam cured blocks
A mixture of lime, industrial waste products like fly ash or expansive soils like black cotton soil and sand can be compacted into a high-density block. Lime reacts with fly ash/clay minerals forming water insoluble bonds imparting strength to the block. These reactions are slow at ambient temperatures (~ 30°C) and hence steam curing for about 10h at 80°C can accelerate these reactions leading to high strength for the block. The process involves:
(a) Mixing of raw materials like lime, cement, fly ash or black cotton soil, sand and water in a mixer,
(b) Converting the mixture into a dense block using soil block press,
(c) Stacking the blocks in a steam chamber and steam curing for 10–12 h.
Blocks of any convenient size can be manufactured. Compressive strength of the block depends upon the composition of the mix, density of the block and percentage of stabilizer (cement/lime). A combination like 25% fly ash, 6% lime and 2% cement can yield blocks having wet compressive strength. This kind of strength will be sufficient to construct 3–4 storey load-bearing buildings with spans in the range of 3–4 m.
Blocks of higher strength can be easily achieved by adjusting the mix proportions. It should be noted here that the block quality is much superior when compared to local burnt bricks and SMB. Advantages of using these blocks are: (i) Ideal process for a small-scale or cottage industry, (ii) utilization of industrial waste products like fly ash and problematic soils like black cotton soil and high clay soils, (iii) energy efficient and environment friendly, and (iv) higher strength for the blocks.
Composite beam and panel roofs
This concept exploits the efficiency of beam and slab construction. The roofing system consists of partially precast or cast-in-situ ribs/beams at certain spacing covered with panels. The panels and beams are connected through shear connectors to achieve composite action. Varieties of options are available for the beams (precast reinforced concrete, rolled steel sections, trussed steel members, timber, steel, concrete composite, etc.) and panels (precast concrete, reinforced brickwork, stone slabs, hollow hourdi tile, reinforced SMB panel, etc.). The profile for the panels could be curved, folded plate or flat. Use of curved shape panels results in a composite jack-arch roof. The beam cross section can also be adjusted to minimize the material consumption.
The major advantages of this type of roofing system are:
(i) possibility of prefabrication and quick erection,
(ii) better quality assurance due to prefabrication,
(iii) savings in volume of materials and hence cost effectiveness, and
(iv) possibility of using hollow panels to increase thermal comfort.
Filler slab roofs
Filler slab roofs are basically solid reinforced concrete slabs with partial replacement of the concrete in the tension zone by a filler material. The filler material could be cheaper or cheaper and lighter. A number of alternative materials can be thought of: (a) brick or brick panel, (b) Mangalore tile, (c) stabilized mud block, (d) hollow concrete block, (e) hollow clay tile/block, etc. Quantity of concrete in the tension zone of the slab that can be replaced by a filler material depends upon the shape of the filler material and the thickness of the solid slab. For example in a solid concrete slab of 125 mm thickness, a filler block of 60–70 mm thickness can be easily accommodated. In a typical situation, by using a stabilized mud block, 25% of the concrete can be replaced by a material, which costs one third the cost of concrete. This means that 15–20% of the cost of concrete can be saved by this operation.
Unreinforced masonry vaulted roofs
Vault and dome constructions using unreinforced masonry have been used in India for more than six centuries. Due to the advent of steel and reinforced concrete these techniques were abandoned during the British colonial period. Because of the advantages like aesthetics, cost, durability and savings in energy, vaults and dome constructions have been revived. Recent work and expertise developed has shown that unreinforced masonry vaults can be constructed using the concept of moving formwork. A metal formwork of about 1 m width defining the vault shape can be repetitively used to construct such vaults. Various shapes can be adopted for the vaults. Catenary-shaped vault is the most efficient. The thickness of the vault is dependent on the span of the vault. A vault thickness of about 100 mm can be used for spans up to 4 m. It is also possible to construct the intersecting vaults as well as hipped vaults.
The Lime–pozzolana (LP) cement is made by mixing calcium hydroxide (lime) and pozzolana in the ratio of 1: 1.5 or 1: 2. Secondary grade lime available locally in many areas can also be used by adjusting the mix proportions. Variety of pozzolonas like burnt clay pozzolona, rice husk ash, good quality fly ash or combination of pozzolonas can be used. Ideally lime and pozzolana have to be inter-ground in a ball mill. But such mixtures have poor shelf life (15 days). Volume proportions of 1: 3 or 1: 4 (LP cement: sand) can be used. The strength of the mortar mix can be easily manipulated by adjusting the proportions of various materials. LP cements are low energy consuming materials and can be used for a majority of secondary applications except for reinforced concrete works.
If Uganda is to cope with growing demand for housing it has to invest in appropriate technologies, materials production, and develop sustainable building designs in terms of energy consumption and environmental pressures.
The programme to construct low-cost houses started in the 1960’s but was hampered by lack of funds. The housing backlog has been worsened by the high urbanization rates in the city. According to the 2003 Demographic Survey 2003, Uganda suffers from a deficit of 1.6 million housing units. The private sector has had an initiative to have houses constructed but the rent charges are too high for the average income earners to afford. Currently, most developers have targeted the middle class. On average, the house rent charged by private developers on housing units cost about UGsh 500,000 per month. The Uganda Bureau of Statistics estimates that by 2025, about 4.8 million people in Kampala will have no houses.
Existing low cost housing projects in Uganda
Housing Project for Health Workers and Teachers in Lango and Acholi
The project introduced an environmentally-friendly and cost-effective method of construction through the use of alternative building materials and technology and injected cash into the communities by using local contractors.
The goal of the project is to facilitate the sustainable return and reintegration processes of Northern Uganda by supporting the provision of basic services, such as health services and schooling by providing housing for teachers and health workers.
The main activities included:
• Construction of 64 teachers houses using alternative building technology.
• Raising awareness and building capacity of local contractors in the use of alternative building technology.
• Supporting the development of standards, norms and designs for the alternative technology with ministries.
• Mobilizing communities to take part in planning, implementation and monitoring of physical construction and tree planting.
BeadforLife Housing Program for Women
BeadforLife is a poverty eradication organization based in Kampala. Since its inception in 2005, BeadforLife has changed the lives of 700 individuals living in extreme poverty (primarily women) with income generation through bead making. About half of the BeadforLife participants are women living with HIV, many of whom are caring for orphans as well as their own children. Others are persons internally displaced by the war in Northern Uganda, or are living with other serious health challenges. Members are taught to make bead jewellery from recycled paper, and are paid fair-trade prices for their products which are sold in the United States of America (USA) and Europe.
Under the BeadforLife program, members generate between Ushs.300, 000 - 400,000 per month. In addition, BeadforLife members are educated about HIV prevention, family planning, & malaria diagnosis as well as prevention through distribution of mosquito nets under the health programme. The members also embark on business planning and skills development within one month of enrolling in the 18-month programme to enhance long-term economic self-sustainability beyond bead-making. Upon graduation from the BeadforLife programme, the women are supported in their own micro-enterprises.
When asked about their number one priority for improving their well-being, it is not surprising that the BeadforLife participants named housing. Thus, BeadforLife took direct and meaningful steps to help improve the living conditions of its members. In 2007, BeadforLife purchased an 18-acre plot of land to develop its Friendship Village in Mukono district. In collaboration with Habitat for Humanity, BeadforLife developed 130 affordable houses. The beneficiary homeowners are given a plot free-of-charge and then take out a mortgage of approximately Ushs.3 million to cover the building labour and supplies. The mortgages are entirely paid off in beads, although beneficiaries are required to make a down-payment of Ushs.1million in cash, leaving the remaining balance of Ushs.2million to be paid in beads. It was revealed that approximately 50 families have already paid off their mortgages.
Friendship Village is an idyllic retreat away from the bustle of Kampala City, with extensive green space, yard gardens, fresh water wells within close walking distance, and neat rows of permanent three-room brick houses. These houses are a far cry from the living conditions the members experienced before joining BeadforLife. Like so many urban poor in Uganda, their living conditions were characterized by substandard buildings with hardly any sanitation & waste management facilities, hunger and overcrowding.
UN-Habitat –Mpumudde Housing Project
The UN Habitat Housing Estate in Mpumudde is a housing project aimed at empowering poor urban women entrepreneurs through housing development and land rights. The project is collaboration between the UN Habitat, JMC and Akright projects LTD. The UN Habitat provided the funding under the coordination of JMC while Akright projects LTD, offered the technical services to the project in kind. JMC allocated 50 plots, about 5.73 acres, to the women’s housing project. The housing scheme consists of detached small single story houses on relatively big plots. The units have initially two bed rooms, one waterborne toilet with a shower, a living room and an outdoor cooking space, but can grow to become a four- roomed unit if necessary. They are accessed through the front yard, while the back yard serves as a “working area” where domestic duties and agricultural activities are practiced. The materials used in the constructions are concrete, in foundations and floor slabs, burnt bricks for walls and iron sheets for roofing.
Namuwongo Slum Up-grading Project
In 1990, the Uganda government embarked on ‘Namuwongo upgrading and low cost housing Project- (UGA/86/005. UNCHS, GOU) and Shelter Afrique at a cost of US $ 4.2M in provided funding. Initially, the area was a slum settlement occupied by over 2,000 households who were being accommodated in 500 dwelling units of very poor quality. The area was large but ownership of 120 acres (51.3ha) was limited to about 180 absentee land lords (Nuwagaba, 1996). The key principle of the project was that of incremental development. The ‘growing house’ principle was used in the design of type of plan and infrastructure. There were approximately 900 plots of (10x25) meters. To achieve the aim of the shelter improvements for the residents, 120 acres (51.3) was acquired and 1,016 surveyed plots were then allocated to beneficiaries using comprehensive prepared criteria. Basic services like water, roads, drainage, and power reticulation were provided in partnership with the private sector beneficiaries. However, due to poverty and lack of sustainable means of livelihood, only, few intended residents did benefit from the project. The well to do grabbed the opportunity, bought off the bona fide holders of the allocates of plots and erected executive structures hence replacing approximately 40% of the original intended beneficiaries who have ironically developed and settled in a nearby slum area (National Action Plan-Habitat 11: 1996; 62).
Masese Women Housing Project
This project was implemented in Jinja town. The project was planned using adoptive approaches. It was executed by a local NGO in collaboration with the target beneficiaries as implementers. The targeted project beneficiaries were poor women who were unemployed. The major economic activity of the women prior to the commencement of the project constituted petty commodity trade, brewing of local liquor and casual labour around Jinja and surrounding areas. The project employed participatory methodologies in the whole process of the project right from identification, formulation, design, implementation, monitoring and evaluation. With the use of state-of –the art knowledge and ‘hands–on -skills’, the women were engrained in skills of producing building materials which they were to use in the construction of their dwelling units. The local women beneficiaries were involved in the design of dwelling units as well as in the actual construction. Small sized dwelling units were constructed with minimum utilities, which include; a pit latrine. In addition to the training women in the production of building materials, they were trained in production of other hardware materials such as san plats, culverts and blocks for sale on the open market. This was meant to facilitate income generation for their day- to- day sustenance. The results indicate that the majority of the women beneficiaries are living in their constructed units.
Alternative Building Material/Construction Documents
- Rammed Earth and Stabilized Soil Tanks (Warwick Uni)
- Stabilised Interlocking Rammed Earth Blocks: Alternative to Cement Stabilisation
- Interlocking Stabilised Soil Blocks - Appropriate earth technologies in Uganda