The 14 hydroponic growing pits required a tank lining in order to protect the concrete from the water treatment chemicals used.
Initially all concrete surfaces were prepared by method of vacuum controlled diamond grinding to remove surface laitance and contamination.
Following preparation a large number of blow holes were present in the concrete surface. To ensure a seamless tank lining these must be first properly filled. For speed and cost effectiveness this was undertaken by method of applying an epoxy grout coat applied using rubberized trowels. It is not possible to fill blow holes with paint alone, something many other contractors fail to properly understand.
Following priming all corners were radiused using a polyurethane jointing compound to isolate these potential points of movement from the new tank lining.
Remmers Epoxy WHG was then applied in two coats, to a total nominal thickness of 800 micrometers by method of brush and roller. This tank lining material was particularly suitable for application to concrete tanks as it can crack bridge to 0.2mm – the design crack width for most site cast concrete.
As part of our standard quality assurance the new tank linings were checked for pin holing using a DC Holiday spark tester. Where found these were marked with chalk prior to touching in using the same material.