Primary Settlement Tank Repair – NATCEM® 35

Project: Primary Settlement Tank Repair – NATCEM® 35

Product: NATCEM® 35.

Contractor: Stonbury

Project Background

A primary settlement tank at a sewage treatment works in the Midlands showed clear signs of deterioration. Cracks had formed on both the internal and external walls, causing leakage. The perimeter coping stones had also become loose and degraded.

Replacing the tank would have been costly, carbon-intensive, and highly disruptive. Instead, Stonbury delivered an expert tank repair solution, completing the works in just over a week.

The Methodology of the Tank Repair

Stonbury’s team mobilised to the site and began by high-pressure water jetting the internal walls. This process removed debris and loose substrate. Next, they removed the coping stones and external render, exposing water leakage from the cracks.

To repair the cracks internally, they saw-cut each to a depth of 10mm using a diamond-blade grinder. Then, Stonbury began to carry out a series of concrete repairs. Once cured following the manufacturer’s Instructions for Use, they coated the entire internal wall with a waterproof render which helped prevent further degradation.

Externally, they repeated the crack repair method before re-rendering the tank’s external walls with NATCEM® 35. Pull tests confirmed the render had set correctly, ensuring a high-quality, durable finish. Finally, they replaced the degraded coping stones and bedded them securely into position.