Epoxy: A Guide to Potable-Water Tank Linings and Industrial Floors

What Is Epoxy, What Is It Made Of and How Does It Work?

Epoxy is a two-component material: an epoxy resin (component A) and a hardener, usually amine-based (component B). Mixed at the specified ratio, they react chemically and turn the liquid into a solid network that does not dissolve or soften with heat (a thermoset). Epoxy therefore does not dry by evaporation like ordinary paint; it cures by reaction, and the speed of that reaction depends directly on temperature and humidity.

Solvent-free systems are 100% solids by volume according to product data sheets, so what is applied stays at almost its full thickness after curing, and no solvents have to evaporate inside closed tanks. That is why they are the preferred choice for tank linings and thick floor systems.

• Primer: a low-viscosity first coat that penetrates concrete pores and improves adhesion.
• Body coat: a roller-applied coating, a self-smoothing mix with graded quartz filler, or a thick mortar for heavy loads.
• Top coat: to seal the surface, add anti-slip aggregate or provide UV protection where needed.
• Dedicated tank lining: a system certified for drinking-water contact, applied to prepared concrete or steel.

Recommended Uses: Where It Fits and Where It Does Not

Advantages and Technical Properties

• A seamless, joint-free surface that is easy to clean and disinfect.
• Good resistance to abrasion and to many chemicals, as listed in the product's resistance tables.
• Strong adhesion to sound concrete and to grit-blasted steel.
• Build-ups from a thin roller coat to several millimetres in self-smoothing systems.

Disadvantages and Cautions

• Yellowing and discolouration in sunlight: manufacturers' data sheets state that epoxy may discolour under direct sunlight and chalk on outdoor exposure. The effect is usually cosmetic, but it makes epoxy unsuitable as an exposed finish unless protected by a top coat the manufacturer recommends.
• Amine blush: a greasy, waxy film or white spotting caused by the amine hardener reacting with moisture and carbon dioxide. It increases in cold, high humidity and near the dew point. It weakens adhesion of the next coat and is removed by washing with warm water, detergent and a stiff brush, then rinsing and drying before recoating.
• Rising moisture: causes blistering and debonding months after application, so moisture content is measured and a plastic-sheet test is carried out before starting.
• Rigidity: epoxy does not bridge moving cracks or structural joints. Joints are treated with flexible materials and cracks are repaired first through concrete repair.
• Short working time in heat: the pot life of one product is about 15 minutes at 30°C versus about 60 minutes at 10°C, so mix in small batches.
• Confined spaces: being solvent-free does not remove the need for ventilation and permits to work inside tanks. See our safety guidance.

Standard Application Steps and Testing

1. 1

   Inspection and pre-tests

   Measure concrete moisture, run pull-off tests, record substrate temperature, relative humidity and dew point, and map cracks and joints.

2. 2

   Surface preparation

   Concrete: grind or shot-blast to remove the weak laitance, then vacuum. Steel: blast to Sa 2½. Fill pits and honeycombing with compatible repair materials.

3. 3

   Primer

   Apply the system primer at the specified rate, broadcasting quartz sand into it where needed to key the next coat.

4. 4

   Stripe coat in tanks

   Brush corners, welds, openings and edges before the full coat, because these are the areas most prone to low thickness.

5. 5

   Mixing and application

   Mix both components completely with a low-speed mixer, then apply by roller, notched trowel or airless spray depending on the system, respecting pot life and overcoating intervals.

6. 6

   In-process measurement

   Track consumption per square metre or measure wet film thickness, then measure dry film thickness with a suitable gauge after cure, and holiday-test (pinhole-test) tank linings.

7. 7

   Curing and commissioning

   Respect the full cure time before loading or filling the tank, then wash the tank with fresh water and detergent and flush it before service, as the manufacturer instructs.

8. 8

   Handover and records

   Hand over the log of weather conditions, measurements, material batch numbers and the product's drinking-water certificate, with a written warranty whose term depends on the insulation type and surface condition.

Climate Suitability by Saudi Region

Estimated Cost

Epoxy flooring typically ranges from SAR 35 to 120 per square metre depending on the system (roller coat, self-smoothing or heavy mortar), and tank lining falls within SAR 60–120 per internal square metre. Prices exclude VAT, are indicative and are confirmed after inspection. The main cost drivers are concrete condition and repair scope, required thickness, the type of drinking-water certification, and access and ventilation. Estimate your project with the cost calculator and compare epoxy with the alternatives in polyurea vs polyurethane vs epoxy.