Treating the inside of concrete tanks usually requires a positive tanking application. Liquid applied membranes are idea for this purpose. The most convenient method is to use an acrylic water based product like FLEXIPRO. The area will need at least two coats. Cracked surfaces can benefit from the use of reinforcing fabric or liquid polyurethane.
EXTERNAL LEAK REPAIR
Treating concrete tanks from the outside requires a ‘negative tanking’ approach. Using the same process as a leaking swimming pool; treat the major cracks first, then coat the surface. When the cracks are opened up, stop the flowing water with Contec PLUG, fill the cracks with a putty of Contec C1. Finally apply a couple of slurry coats of Contac C1 over the broader area. The other method of treatment is to apply a vapour barrier to the surface, not allowing moisture to penetrate the external skin.