The use of hydraform building blocks produced by hydraform machines is expected to boost the construction of affordable housing.

The hydraform blocks, also known Interlocking Stabilised Soil Blocks (ISSB), are made of a mixture of soil, cement and water.

The machines will help the government achieve affordable, decent and durable houses, according to Workforce Development Authority (WDA).

The Deputy Director-General in charge of training at WDA, Irenée Nsengiyumva, made the remarks during an Open Day – a day when training centres are open to the public to see what they train in – at the Integrated Polytechnic Regional Centre (IPRC) South last week.

The Day was intended to raise awareness about the Technical and Vocational Education and Training (TVET) and discuss ways TVET implementation in Southern Province could be reinforced.

During the event, 30 people in the construction field, including masons, teachers and students at IPRCs as well as those from TVET centres were awarded certificates after completing a one-month training in the use of the hydraform machines.

A structure constructed with hydraform blocks is 30 per cent cheaper than with conventional bricks. Experts say hydraform is also more durable.

Nsengiyumva said Rwandans should make the most of such machines so they can benefit the country. There are now five machines in the country, which were bought from South Africa in January 2015 by WDA with each worth $34,000.

"The machines are of advanced technology and will help in the construction of affordable and durable housing units. They should be used effectively to achieve the desired goal,” he said.

Nsengiyumva urged those trained to also train others in the use of such machines to maximise their utility, adding that the private sector should invest in the technology to benefit more people.

Operation of the machine

A hydraform machine has capacity to produce one block per nine to 14 seconds or 2,200 hydraform blocks per day, and consumes 13 litres of diesel to perform the work.

A 50-kilogramme bag of cement can help produce 45 hydraform blocks, each weighing between 10 to 12 kilogrammes. The quantity of soil would be 12 times the quantity of cement and the soil should have not more than 13 per cent of clay in it.

A hydraform block costs Rwf120 and it can take up the space of four conventional bricks.

"Building those blocks is easier as a constructor can lay 400 blocks compared to 100 conventional bricks he can lay per day. Through the use of such a machine, an estimated 100 housing units could be erected within a year,” Fred M Owambo, the Hydraform International country representative, said.

Trainees said the hydraform blocks are user-friendly and expressed readiness to impart the acquired skills to other people.

Angelique Musabyimana Nyakayiro, a graduate from IPRC Kigali, said: "Those blocks do not necessitate cement between them. You have to interlock them until the house gets complete. We want each district or technical school to have its own hydraform machine so that we can teach more people to use them.”

IPRC South principal Barnabé Twabagira said the machine would generate revenue and help communities as the hydraform blocks are cost-effective.

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