FRP Water Treatment Tank Lining Guide

Concrete and steel water treatment tanks suffer from corrosion and leakage after years of service. An FRP (glassfiber reinforced plastic) lining restores the tank in place without demolition, offering a seamless corrosion barrier that bonds to the substrate. This guide explains when and how to install an FRP lining.

When to Line Instead of Replace

If the concrete structure is structurally sound but shows surface scaling, cracks, or leakage through the walls and floor, an FRP lining is usually the most economical solution. For potable water tanks, select resin systems certified for contact with drinking water. For wastewater and chemical tanks, choose a corrosion-resistant vinyl ester liner.

Surface Preparation

The substrate must be grit-blasted to a clean, open texture before lining. Fill cracks and spalled areas with epoxy putty; trowel them flush. Oil, grease, and loose particles must be removed. A damp surface prevents good adhesion, so allow the tank to dry to the required moisture content.

Lamination Steps

• Apply a primer coat that bonds to the damp concrete or steel surface.

• Lay chopped strand mat or woven roving with a brush or roller, wetting out every layer and avoiding air bubbles.

• Build up to the specified thickness (typically 3 to 5 mm for potable water, 5 to 8 mm for chemical duty).

• Spark test the cured liner to detect pinholes; repair defects before filling.

Curing and Commissioning

Allow the resin to cure fully according to the resin supplier's schedule. Flush the tank with clean water, fill gradually, and inspect the walls and floor for weeping before returning to service.

Conclusion

An FRP lining extends the life of a leaking water treatment tank at a fraction of replacement cost. Proper surface preparation and lamination quality determine how many years the new barrier will last.

References

• AWWA D102 — Organic Coatings for Steel Water Tanks

• ASTM D412 — Standard Test Methods for Vulcanized Rubber