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Teacher who turned to brick making now earns Sh90,000 a-month

By Nikko Tanui | January 9th 2020
Mr Francis Tonui outside his eight-bedroom dream house that he built using interlocking blocks.

In 2014, Francis Tonui wanted to build his dream house.

But when he visited a contractor to find out how much it would cost, he was taken aback when he was presented with a Sh16 million Bill of Quantities.

A dejected Tonui could see his plan of owning the house of his dreams slipping through his fingers.

As the Maso Secondary School principal was scratching his head on how he could slash the huge cost of constructing a spacious eight-bedroom house, he stumbled onto a construction site, where interlocking blocks were being used. 

“Upon inquiring from the contractor the materials used to make the interlocking blocks, I realised that besides cement, the other raw materials required was available in my farm in Soin ward. It opened my eyes to the fact that I could make the interlocking blocks myself,” says Tonui. 

“That is how I managed to build my spacious eight-bedroom house at Sh10 million, which is Sh6 million less if I could have used conventional building blocks.”

He says interlocking blocks slash the cost of construction by almost 15 per cent due to what is known as ‘zero joints’.  

“No cement is used on the joints. The interlocking blocks interlock themselves due to the ‘male and female’ sides, which fit into each other perfectly,” said Tonui.  

After the completion of the house, and having been satisfied with the results, Tonui decided to venture into making interlocking blocks.

“I decided to shelve the idea of selling the certified raw material from my five-acre farm in Kapkormom village to a road construction company undertaking road construction works along the Brooke-Ainamoi-Thessalia road,” said Tonui.  

He began a commercial interlocking blocks business by hiring experts and a Hydraform machine supplied to the Nyamira Ministry of Housing and Public Works (as it was known) office as part of the government’s affordable housing project. 

“But after encountering delays and bureaucracies in the hiring of the Hydraform machines from Kericho, Bomet, Narok and other counties, I decided to raise Sh4 million and import my own machine from South Africa,” says Tonui.


To make the interlocking blocks, the businessman mixes cement and a mixture of sand and murram at the ratio of one bag of cement to 16 wheelbarrows of the sand and murram mixture. “This must be the rate,” says Tonui.  

In a day, the businessman produces 1,000 to 1,200 blocks. A work force of 10 people is required for the work.  

“One of the workers operates the Hydraform machine while the rest are involved in the mixing of the raw materials and carrying the blocks to the curing area,” says Tonui.  

In the curing area, the building blocks have to be stacked and kept moist by sprinkling of water twice a day and covered using a polythene sheet.  

The curing process for the bricks takes at least 21 days.  

Once the process is complete, the businessman sells the interlocking blocks at site at Sh30 a piece. 

“In a month, I can sell up to 10,000 interlocking blocks. This earns me a profit of around Sh90,000,” said Tonui.  

Tonui says a house, or any other building, constructed using interlocking blocks is stronger than any other.  

“The lifespan is more than a 100 years. Due to the weight of the interlocking block which is about eight kilogrammes, even a tractor cannot smash through the wall.... Interlocking blocks are like three bricks joined together,” he says.  

Tonui explains that one can distinguish a good interlocking block from the rest if it isn’t crushed when pressed down through the Hydraform machine.  

“An interlocking block with the right ratio of cement and other raw materials, and is also cured well cannot crack,” he says.   

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