Concrete Repairs For
Water Infrastructure

Specialist concrete repairs for water and sewer Lines

Contech is the New Zealand distributor for the SewperCoat system for water and wastewater applications.


Imerys SewperCoat is engineered to provide superior concrete repairs, especially in the harshest water and wastewater environments.

With over 40 years of international use and applied in over 30 New Zealand wastewater structures over 20 years, Sewpercoat offers proven protection against the effects of biogenic corrosion. It can extend the life of critical infrastructure, providing a long-term solution for structures exposed to destructive biogenic corrosion throughout their working life.


With SewperCoat you’re not just repairing concrete; you’re investing in the long-term integrity and longevity of critical infrastructure.


New structures can be protected against the effects of biogenic corrosion with a layer of SewperLiner. SewperLiner is applied to new concrete surfaces and requires no special preparation.

Sewer line repairs to withstand the toughest challenges

The combination of physical and chemical bonds between the calcium aluminate cement and aggregate produces a superior concrete capable of withstanding the toughest combinations of thermal cycling, high heat, mechanical shock and biogenic corrosion.


Biogenic corrosion in wastewater occurs when bacteria create sulfuric acid. This acid harms concrete and steel, causing degradation. SewperCoat resists biogenic corrosion through a combination of many factors, but predominantly through neutralising and inhibiting the growth of the bacteria strains present in the wastewater environment.

Key benefits of wastewater repairs with SewperCoat include:

  • Outstanding H2S biogenic corrosion resistance
  • Easy granolithic installation
  • Readily adheres to damp concrete surfaces
  • High early strength
  • High abrasion resistance
  • Can be applied in a live sewer environment
  • Restores structural integrity
  • Rock solid barrier to infiltration
  • Without volatile organic compounds
  • Economical to apply and cost-effective in the long run
  • Makes sense for sustainable development

Extended infrastructure life for improved sustainability

By applying Sewpercoat and SewperLiner, clients can significantly extend the life of vital infrastructure. In an era where infrastructure sustainability is of utmost importance, our high-performance concrete repair solution ensures that structures exposed to destructive forces and corrosive substances can continue to serve their purpose effectively for many years. Sewpercoat is more than a quick fix; it’s a commitment to safeguarding the future of your infrastructure investments.

Versatility for any wastewater repair project

Imerys Calcium Aluminate Solutions for wastewater are available in three distinct formulations to meet the specific needs of different applications.


Sewpercoat PG25 is ideal for low-pressure wet applications in small chambers and when the pumping distance is less than 20 metres.


Sewpercoat HS40 is designed for high-pressure dry gunite application, providing exceptional strength and durability. Able to be conveyed up to 100 metres from the pump it is ideal for large diameter pipes and structures with limited access.


SewperLiner is specially formulated for new structures and will provide up to 15 years of protection against the damaging effects of biogenic corrosion.


Contact us today to explore how Sewpercoat can address your wastewater concrete repair needs.

Recent Sewpercoat Repair projects:


If you would like some advice on a project or need a quote tell us a little about the project and the relevant expert will get back to you soon.