The Tank Relining Process
When a water tank starts leaking or showing signs of internal damage, full replacement isn’t always necessary. If the structure is sound, relining a tank is often a faster, more cost-effective solution. By applying a new protective lining inside the existing tank, we can create a durable, watertight barrier that restores performance and extends lifespan, without major disruption. Our specialist linings are WRAS approved polyurethanes, ideal for concrete, steel, and GRP tanks facing corrosion, cracks, or general wear and tear.
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At Titan, our engineering team reline dozens of tanks every year, in all kinds of challenging environments. We tailor each job based on the operational needs of the client and the condition of the tank. To give you an idea of what's involved, we have shared a step-by-step breakdown of the relining process below - explaining what you can expect, the things to consider and the order in which things are done.
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1. Survey and Specification
Every project begins with a detailed site survey. We assess the tank's condition, measure dimensions, and identify any structural or compliance issues. From there, we produce a tailored specification that outlines the materials, preparation methods, and relining system we’ll use to ensure a long-lasting, safe and effective solution.
2. Temporary Tank or Bypass (If Needed)
To keep your operations running, we can install a temporary water tank or set up a bypass system. This ensures you have a continuous water supply while the main tank is offline. It’s all planned in advance, so there’s no disruption when we begin the work on site. Check out this case study for a real world example. Leaking Water Tank Reline London | Titan Mechanical Services
3. Drain Down and Clean
We fully drain the tank and remove any sediment or debris. A thorough clean follows, stripping out scale, sludge and biological build-up. This step is essential - it gives us a clean, stable base to work from and ensures the polyurethane bonds properly to the tank surfaces.
4. Surface Preparation
Using mechanical abrasion techniques like rotary wire brushing or grinding, we roughen the internal surfaces of the tank to achieve a raised profile of at least 75microns. This not only removes corrosion and loose coatings but also creates the perfect profile for the polyurethane to adhere to. It’s a crucial step in achieving a durable, long-term finish.
5. Stripe Coat to All Vulnerable Areas
We apply a focused “stripe coat” to all edges, joints, bolts and seams - basically any high-risk areas prone to early failure. This additional layer of protection ensures these points are sealed tightly and strengthens the overall performance of the final coating.
6. First Coat of Polyurethane (500 Microns)
The first coat of polyurethane is applied evenly across the entire tank surface to a wet film thickness of 500 microns. This forms the foundation of the new lining system, providing chemical resistance, flexibility and a seamless barrier that protects the structure from corrosion and water damage.
7. Second Coat of Polyurethane (500 Microns)
Once the first layer has cured, we apply a second coat - again at 500 microns. This builds up the overall thickness, ensures full coverage and eliminates weak spots. Together, the two coats form a robust, WRAS-approved lining that meets the highest standards for potable water storage.
8. Cure, Refill, Disinfect
After both coats are applied, the lining is left to cure for the recommended time - usually 24 to 48 hours depending on conditions. Once fully set, we refill the tank, disinfect it thoroughly, and test to make sure it’s ready for safe use again.
9. Return to Service and Remove Temporary Supply
Once the tank passes final checks, we bring it back into full service and, if we installed a temporary water supply, we’ll remove it cleanly and efficiently. You’re left with a fully relined, compliant water tank that’s ready for the long haul.
If you'd like to learn more about tank lining and refurbishment, then visit our case studies section, which offer a glimpse into the challenges faced and the innovative strategies our team have employed to deliver excellence for our customers.
