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Low cost building technologies the way to go

By | March 11th 2010 at 00:00:00 GMT +0300

By Pocyline Karani

Building technologies expected to revolutionise the construction of low cost housing are coming up, with new breakthroughs now offering up to 60 per cent cost reduction.

Even as the building industry grows, the dire need for housing especially at the lower end of the spectrum persists. It is paradoxical that the country is seeing a housing revolution of sorts because if you look closely, most of what is being built is inaccessible for the lower income masses, resulting in the bitter truth that every six out of ten Kenyans live in a slum.

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"You do not ignore these statistics. Any right thinking and strategic business mind knows that great potential lies here and already this segment has captured the interest of many investors with venture capital organisations joining in," says Moses Kiroko of Makiga Engineering Services limited.

Low cost technologies

Kiroko stresses that the future of Kenya’s real estate depends on the ability to introduce affordable technologies whose investments will avail affordable homes to the larger underserved population.

Investigations reveal that permanent walling and roofing materials are what many organisations selling low-cost building technologies are focussing on. From stabilised soil blocks, prefab materials to structural insulated panel technologies, all lay focus to addressing the ever-growing building shortfall.

"The cost of building is not set to take a downward spiral anytime in the future. It is with this background coupled with the increasing demand for affordable housing that there is a sudden interest in developing technologies that will avail decent homes for the lower income cadre," adds Kiroko.

Makiga Engineering Services, a locally owned company that manufactures a range of machinery used to make walling, roofing and now the new concrete crusher, is one of the few players in this market segment.

Two of Makiga’s interesting ecological friendly products are radically altering the building landscape especially in parts of the country where quarry stones are unavailable. These are the Soil Block Press (SBPs), which produce Stabilised Soil Blocks (SSB) and the micro concrete roofing tile unit

A complete house

"The SBP makes building blocks using a mixture of soil from site and cement. It has further been improved to give it the ability to produce straight interlocking bricks of different sizes and curved interlocking blocks used to build circular structures such as water and sanitation systems," says Kiroko.

Affordable roofing

The interlocking building blocks eliminate mortar used to bond building in traditional buildings. On the other hand, the micro concrete roofing tile unit aids in the production of affordable roofing also made from basic materials such as sand, cement and sisal fibre. Currently, these machines are manually operated but Makiga is looking at the possibility of motorising them while ensuring the cost of operating remains significantly low to maintain the target market.

This is expected to rival South Africa’s motorised hydrofoam, which costs US$ 33,000 (Sh2.5 million), "...far beyond the reach of many middle income earners and whose cost of operating and maintenance are equally high," said Dr Solomon Mwangi, Managing Director of Construction Management and Consulting Services (Comac).

A Ministry of Housing steered project in Mukurueni using Hydrofoam technology has proven costly to run and hence an ineffective ecological technology to address the challenge of housing the poor. In comparison to Hydrofoam, the manually operated SBP retails for Sh75,000-90,000, making it 30 times cheaper hence is within reach of many. It employs four to six people and has a capacity to produce 400 blocks a day.

"With one Hydrofoam, one is able to acquire 30 SBPs, which will create 180 jobs, making it ideal to address the issue of poverty," says Dr Mwangi.

According to a research by three researchers at the Department of Urban and Environmental Engineering, Kyoto University, Japan, to determine the feasibility of the SSB, it was found that the technology could reduce housing cost, especially using pozzolan admixture. Pozzolan is a finely-divided material that reacts with calcium hydroxide and alkalis to form compounds possessing cement properties. Enormous amounts of this raw material have been found in Rift Valley and can be extracted for commercial purposes.

Upon comparing the motorised Hydrofoam and the manual SSB, the findings emerged in favour of the manually operated machine, which produces 400-500 blocks a day with each costing Sh12. The motorised machine, which produces 2400 blocks a day and employs 11 people, made blocks costing Sh14.

How it works

Cement, which makes up three per cent of the blocks, is mixed with soil, the main raw material and water. Cement to soil ratio varies according to soil type and can be determined by testing the soil for shrinkage.

Other than the SSB technology, Comac also offers ecology-friendly roofing material that has witnessed sudden demand propelled by a need for cheap yet durable roofing material.

"There is an increasing demand for cheap and durable roofing material in developing countries faced with an ever increasing shortage of timber supply. Deforestation has spread fast in the Sub-Saharan region with many trees being felled for firewood and building construction. This continues to make construction using timber very expensive and environmental unfriendly," says Dr Mwangi.

With this in mind, Comac has developed a roofing technology, which uses cement mixed with sand and latex in predetermined ratios, which is applied on canvas or shade-net.

The technology uses simple timber or metal structure deriving its strength from the design or shape such as domes and hyperboles. This technology does not only conserve trees but offers good thermal insulation ideal in hot climates.

Poles and rammed earth

Poles and rammed earth technology is an improvement on the traditional poles and mud construction. Treated poles or recycled plastic are used as the structural, load-bearing framework of the building.

The gap between the poles is filled with soil stabilised with cement, manually compacted. Barbed wire or hoop iron is nailed between the poles to provide anchorage of the rammed earth to the poles.

The challenge in Kenya, however, even as Comac successfully works with the Sudan government to eradicate slums as well as house the internally displaced in Darfur, Dr Mwangi says, is the issue of land tenure.

Building code

"Land ownership is a huge impediment when housing the poor in Kenya. The Government of Sudan has offered land to the people and extended credit facility where cement is given on loan basis and Comac with the assistance of a UN body trains the mobilised community on use of the SBP machines," he says.

With land and basic infrastructure in place, achieving housing for all status is within reach. The other challenge in Kenya is the perception that cheap is not up to standard and especially in urban areas and the city. Similarly, the building code, still under review does not support the use of such materials in construction of homes within cities and towns. Kiroko says Makiga has been lobbying for the change of the said clauses through the Ministry of Housing because demand for this technology in areas like Mlolongo, Kitengela and slums is very high.

He notes that this technology is highly in demand and already extensively in use in Uganda’s capital, Kampala. The advantages are vast. One bag of cement produces 150 blocks with a two-bedroom house requiring approximately 40 bags of cement. According to findings by Kyoto University, a structure occupying 120mm2 made from SSB costs Sh720,000 while one constructed from concrete block costs Sh2,226,000. Other than cost benefits, the ecological aspect makes it ideal compared to burning of bricks in kilns fired using wood.

The roofing tiles compared to other local roofing tiles cost between Sh25-Sh30 compared to Sh45-Sh50 of other roofing tile products.

The use of prefabricated building material has been around for years with industries using them to set up operating spaces. One such technology is Bamburi Special Product’s pre cast concrete Panel, which in collaboration with Ecohomes, has built housing for Parliament staff in Mlolongo.

"Using this technology, a two-bedroom house can be installed in 21 days, a good saving on construction period and a cheap option on construction material compared to the conventional methods," says Bamburi.

The modular building material market has also interested investors from as far as the Far East. Afro Homes, a venture capital organisation, provides building solutions, Structural Insulated Panels (SIPSs) that have tremendous advantages over traditional construction methods.

"These are high profile performance building panels made by bonding, under extreme pressure, cement fibre boards onto both sides of an expanded, rigid polyurethane foam core. The end product is a tight, well-insulated shells that take less labour to construct, are strong, versatile and more durable than conventionally constructed buildings," says Mutheki Gichanga of Afrohomes.

Unbelievable strength

"Buildings made with the panels are energy efficient, resistant to fire, water, wind, mould, snow loads and earthquakes; and much faster and easier to construct. All this results in significant savings for builders, owners, and the environment," Gichanga adds.

While SPB cannot be used to build multi-storey buildings, insulated panels by Afrohomes can build maisonettes and flats.

"The panels have unbelievable strength due to the stressed skin technology used in their manufacturing, giving the ability to construct foundation or basement walls even below ground," says Gichanga.

According to Gichanga, a three-bedroom, two-bathroom on 150sq metres will costs Sh2.9 million, almost two times cheaper than a house made from traditional blocks and mortar

Building Industry Constuction Low Cost housing Eco friendly
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