By Michael Oriedo
Recent surveys by Hass Consult, a real estate firm, indicate that prices of properties rose significantly last year. Prices of houses in Nairobi, for instance, rose by about four per cent.
While this is good for property developers and perhaps the country’s economy, the increase spells doom for people in need of decent houses as many are locked out of the property market.
Real estate experts, however, attribute the rise to high costs of building materials. It is believed that if the country adopts cheaper building materials, the cost of houses would reduce significantly. One such material is eco-blocks. These are blocks made from compacted or stabilised red loam soil mixed with minimum cement.
Cheap
"The blocks are made in such a way that they use minimum cement and sand, therefore, making them cheaper," says James Mogaka, an engineer at Jomo Kenyatta University of Agriculture and Technology.
When making the blocks, red loam soil is mixed with cement in the ratio of ten to one.
According to Mogaka, one must use red soil while making the blocks because unlike black soil, the former is stable. The blocks are made using an eco-block machine. The machine has two main parts; a compartment where soil is filled and a bar for compressing the soil.
"Once the soil is mixed with cement and water in the correct ratio, you fill it in the eco-block machine to the brim," says Mogaka.
Afterwards, using the compressing bar, one slowly compacts the soil in the compartment.
"It takes only a few seconds of compressing and your block is ready. You then remove it and put it under a shade. The machine makes about 300 blocks of sizes eight by six inches in a day,’’ he says.
Drying
The blocks will then dry as they are watered for a maximum of 14 days. "And as the blocks dry, they must be watered every morning and evening," says Moses Njeru, a technologist at the institution.
Interestingly, the blocks do not require baking in kiln as happens in brick making.
"The little cement that is used in the compaction process helps to make the blocks strong and durable," says Njeru.
Mogaka says the soil used in the construction of the blocks is readily available hence making the blocks cheaper. The blocks have grooves, which make it possible to interlock them during construction.
"The interlocking grooves help to reduce the use of cement during construction. You only use cement in the foundation and in corners where you place pillars," explains Njeru.
Using eco-blocks in building houses reduces the cost of construction to between 40 and 50 per cent. Once the house is complete, one needs to plaster it, as it is normally done with other blocks.
If this building technology is embraced, Mogaka says it will help reduce the cost of housing and eliminate mud houses. Anyone can operate the machine used in making the blocks since it does not require skilled labour.
Currently, the eco-block making machine costs about Sh70,000.
