By Peter Oliver Ochieng

As a United Nations (UN) official, Kizito Khisa travelled far and wide, getting an opportunity to interact with people from various backgrounds, besides being able to experience, learn and witness life changing events and technologies with a hope that one day, he will be back home to implement some of the ideas collected from around the globe.

During one of such travels, while on board a Kenya Airways (KQ) flight in the 90’s,  Khisa got hold of a brochure which was advertising machines meant for producing interlocking blocks. The company was based in South Africa. He vowed to purchase that machine and venture into production of interlocking blocks after retiring.

Now retired, the 56-year-old man is back at home in Khalaba Ward, Kanduyi Constituency in Bungoma County, and he is in the business of producing interlocking blocks. He started the venture in 2019, after acquiring the Hydraform machine from South Africa at a cost of about Sh1 million (about USD 10,000).

“This is green technology at its best. Ingredients for making these blocks are cement and soil. There is no burning like what happens during production of normal bricks, which means there is no polluting the environment through releasing smoke into the sky,” said Khisa.

One interlocking block goes for Sh30 (about USD 0.3) compared to a normal brick which is sold at Sh7 (about USD 0.07). However, while using bricks for construction, you will need cement, water and sand. Those requirements do not exist while using interlocking blocks for construction.

Kizito Khisa poses next to ready blocks
Dry and ready interlocking blocks

Khisa said that after production and drying (which takes 3 to 14 weeks depending with weather patterns), interlocking blocks are just arranged during construction, automatically doing away with the use of sand and cement.

“In terms of construction, these blocks really make construction of houses or perimeter walls extremely affordable,” he said.

“This block is bigger than the normal brick. Its measurement is 7 by 9 inches. That means you will be able to use 5,000 interlocking blocks to construct a 3-bedroom house. On the other hand, you will need more than 5, 000 bricks to come up with a same sized house. Add the cost of water, cement and sand, and you will realize interlocking blocks are by far affordable.”

The Hydraform machine is being operated by Titus Mukachi, an alumnus of the Kenya National Polytechnic. He has acres of experience in as far as production of the interlocking blocks using the machine is concerned.

He said the production process starts with harvesting or collection of normal soil, with loam soil being the best. In the absence of loam soil, any can do – even the one easily accessible from roadsides.

Sorting is then done to ensure the soil is minus external particles like nails, which may end up destroying the machine. 6 wheelbarrows are then mixed with a wheelbarrow of sand, 1 a bag of cement and water proof.

“The water proof is meant to ensure that the blocks remain strong during rainy seasons after construction,” he said.

Mixing of sand and cement before start of production of interlocking blocks

The mixture is then fed into the Hydraform machine and crashed through the use of force by the operator, and within seconds two level blocks come out through the outlet. Somebody else is on standby to collect the blocks and carefully arrange them at a designated area for them to dry.

The machine uses electric power. During production, three people coordinate to make work effective. The first person’s role is to feed the machine with the mixture; the second one is there to press the mixture into the machine, mostly done by the operator while the third person’s role is to collect the ready blocks.

“This work is normally intense. It needs proper coordination and alertness. A mixture of 6 wheelbarrows of sand, a bag of cement and water proof is capable of producing 83 high quality interlocking blocks,” said Mukachi. The machine is able to produce 500 blocks per day.

Production of interlocking blocks on going

Khisa and company continue to leave a mark in Bungoma as far as the production and use of interlocking blocks in construction is concerned.

Consaga Wanjala has put up a 120 by 110 meter square perimeter wall around his compound, in Khalaba Ward.

“They produced 10, 000 blocks and my wall was done within a matter of days. In order to complete this wall, I would need 20, 000 bricks which is by far very expensive,” he said.

Since one interlocking block goes for Sh30 (about USD0.3), Wanjala used Sh300, 000 (about USD 3000) to get the job done. On the other hand, he would need 20, 000 blocks to complete the job if he was using bricks.

Since a brick is sold at Sh7 (about USD 0.07), he would need Sh140, 000 (about USD 1400) to buy 20, 000 bricks. If you add the cost of buying cement and sand, the total cost would stagger to more than Sh500, 000 (about USD 5000).

“The cost of production is much lower as compared to producing other building materials like stones or bricks. A building or wall constructed using interlocking bricks looks very appealing to the eye. It is nicer compared to stones or even bricks,” Wanjala said.

A house constructed using interlocking blocks

“The time of construction is less while using interlocking blocks when you compare to time taken while using other building materials. You just need to have them produced and then after 3 or 4 days of drying, you go and arrange them.”

He insisted that construction of houses or walls using the interlocking blocks is the way to go.

“For anybody seeking to build affordably and quickly, this is the way to go. Additionally, because of non usage of sand, water and cement, the construction site is always very clean. It is a very clean job,” added Wanjala.

Sister Jacinta Kisangau is another beneficiary of the technology. She is the administrator, St. Damiano Mission Hospital in Khalaba Ward. Recently, she constructed the institution’s wall using interlocking blocks. It is a 400 meter perimeter wall.

“They are very economical in terms of production and construction in that you use little cement while producing and no cement while arranging. You use normal soil and very little cement just to make them compact. I would advise anyone planning to put up a wall or a building to go for interlocking blocks,” she said.

However, Kizito Khisa cites lack of a ready market as a key challenge.

“This technology is somehow new in this county making it a bit difficult to get a ready market. However, as we continue to produce them and sell to our clients, we hope the use of interlocking blocks will be embraced for affordable construction experiences,” said the investor.

He said they will continue producing and marketing the blocks to make them entrenched in the society