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Increased Demand for Concrete Retaining Blocks following KZN floods

The severe flooding that caused extensive damage to infrastructure and buildings in KwaZulu-Natal in mid-April has resulted in an increased demand for GEOLOK earth retaining systems.


GEOLOK was introduced in 2001, with the GEOLOK 300 concrete block for walls typically up to 2 m high and the GEOLOK 400 for walls higher than 2m. Recently the GEOLOK 300 and 400 concrete blocks were modified and improved with the face of the blocks being the same dimensions, that is 400 mm (width) x 200 mm (height).


Only the depth of the block varies in size, allowing the blocks to be interchangeable on the vertical plane.

Corobrik GEOLOK concrete block installation taking place at Kindlewood Estate in Mount Edgecombe (1)
Corobrik GEOLOK concrete block installation taking place at Kindlewood Estate in Mount Edgecombe

Chris Mungle Corobrik eThekwini Sales Manager
“It is a phenomenally successful system with significant market penetration in KwaZulu-Natal,”

Chris Mungle

eThekwini Sales Manager


The GEOLOK blocks are manufactured exclusively by Corobrik in Durban.




The GEOLOK range was also extended the range by introducing the GEOLOK 500 concrete block. This block is ideal for specialised applications where the required slope of the wall could exceed an angle of inclination greater than 70°.


Corobrik GEOLOK concrete block installation taking place at Kindlewood Estate in Mount Edgecombe (1)
Corobrik GEOLOK concrete block installation taking place at Kindlewood Estate in Mount Edgecombe

The benefits of the new GEOLOK range are:


  • Layout flexibility - Three different sized blocks provide walling solutions for different site conditions.

  • Interlocking - GEOLOK 300 and 400 have a visible mechanical interlock in the form of a nib for additional shear resistance to block-on-block sliding.

  • Versatile - The GEOLOK 300 and 400 have a nib to ensure a maximum angle of inclination of 70° when laid horizontally. The GEOLOK 500 excludes a nib, allowing for an angle of inclination greater than 70°.

  • Cost-effective - The open face application requires less blocks per square meter and is therefore more cost competitive than closed face retaining block applications.

  • Plantable - The range is ideal for planting low water-use plants and softening a wall. The design also allows water to drain back into the ground. Using low water-use plants, one can create a landscape that is fully sustainable.


Corobrik has a free software design program to assist professionals and geotechnical engineers design GEOLOK earth retaining walls. Click below to visit the GEOLOK page for more information.




The performance of a GEOLOK wall depends totally on the adequacy of the overall system and not the block alone – that is, design, workmanship, and quality of the concrete retaining block. It is recommended to use tried and tested concrete retaining blocks that are SABS 508:2012 certified.


It is important to note that all concrete block earth retaining walls above 1m in height should be designed by an engineer or a geotechnical engineer. The walls must comply with local building regulations.



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