Claims by Stumbelbloc, the manufacturers of interlocking concrete blocks which require minimal bonding material, that their system can cut building times by up to 50 percent were verified recently when a team of one bricklayer foreman, two handymen and four labourers completed the blockwork of a two bedroom 42m² cottage in six hours.
The finished home at the indoor riding school at Joostenbergvlakte near Cape Town is open to the public for inspection.
See for yourself
Although the total cost of the completed cottage was only R57 000 (excluding VAT), the quality of the structure is far superior to that of normal low cost housing standards. This, says Andre Esterhuizen, CEO of Stumbelbloc, had been confirmed by all who have seen it.
"Those who have inspected the house," Esterhuizen said, "have been impressed by the fact that not only was it built so quickly (in three days altogether), but also that only six bags of cement were needed to bond the brickwork and only 0.46m³ of Skimplaster rendering were needed to render the exterior of the house – at a far lower cost than that of conventional plaster.
"What is more, the rubble created by the operation amounted to only two wheelbarrows."
The 15kg, 200mm x 400mm Stumbelbloc block weighs the same as a 140mm x 390mm block and is denser because it is wet cast.
"This density," said Esterhuizen, "enhances the block’s thermal qualities which are already at a high level as it has cavities which are kept open during the construction process. Thermally, therefore, it performs in a similar fashion to a cavity brick wall."
No electricity was needed during the building process and, as all piping and cabling could be fitted into the cavities, no cutting of the walls was necessary.
"The Stumbelbloc system makes it possible for anyone, even those with limited or no building experience, to erect a cottage in their backyard, factory or farm for less than R2000 per m²," said Esterhuizen. "If the construction sector would adopt the Stumbelbloc system, RDP houses could be built without mechanisation at a rate never seen before in South Africa – and let us not forget that a house of this kind can generate 20 jobs for unskilled people per day in the block manufacturing process."