Water tank waterproofing in Unaizah: without breaking

Prepared by the technical team · editorial review · last updated 13 November 2026 · Sources

Before we start: what we know about Unaizah

Team note on Unaizah: Kashf teams serve this city and its nearby districts with the same documented inspection standard: device-based leak detection without demolition, a written report, and a clear scope before any work begins.. The centre of Unaizah sits about 667 m above sea level (SRTM open elevation data).

Water tanks in Unaizah most often fail at the joints and along the cracks where the floor meets the walls, not in the middle of the panels. Years of filling and draining, combined with temperature swings, open hairline cracks that let water seep through, and the first sign is usually damp patches on the outside of the tank or a faint taste or colour change in the water. Because the work is done on a tank that is still in use, the usual answer is crack injection and a tank internal coating, which seal from the inside without the need to empty and dig out the structure.

The Unaizah setting shapes how we approach this. The centre of the town sits about 667 m above sea level (SRTM open elevation data), so the area can see strong daytime sun on exposed roofs and cooler nights, and that cycle keeps stressing the concrete and the seals. For that reason, the plan usually starts by repairing any cracks, then applying a tank internal coating, and only then considering whether the rooftop tank or its roof needs liquid roof waterproofing (SAR 10–25 per m²) or a bitumen membrane (SAR 15–35 per m²). Where the tank sits on a roof, a single crack repair alone rarely solves the problem, so checking the surrounding surfaces is part of the same visit.

Before the visit, ask the provider to confirm which parts of the tank they plan to treat and how they will keep the water supply safe during the work. Ask whether the price is quoted per square metre or per metre of crack, since crack injection is priced at SAR 40–115 per m and the internal coating at SAR 25–55 per m², and make sure the quote matches the areas you actually have. Ask how they will prepare the surface and whether the coating they use is suitable for drinking-water tanks. A clear, written scope before work starts makes it much easier to judge the result afterwards.

The aim is to locate the cause with instruments first, so any opening is limited to one point.

When do you need water tank waterproofing?

The following signs are worth checking before they grow:

• Deposits and flaking inside the tank
• A tank that leaks after testing
• Unusual colour or taste in the water

Causes we see in the field

• Cracks in the walls or floor.
• Damaged old coating — we check this before anything else.
• Construction joints.

How we choose the tool in Unaizah

From the first visit to the report

1. Emptying and ventilation: The tank is emptied and ventilated before entry.
2. Cleaning and preparation: Loose material is removed down to a sound surface.
3. Crack treatment: Active cracks are treated first.
4. Coating layers: A material intended for drinking-water tanks is applied.
5. Disinfection and fill test: The tank is disinfected and the level is monitored after filling.

Unaizah in facts and sources

Questions from Unaizah

Mistakes that cost more

• Using a material that is not intended for drinking water

The written outputs

You receive: the material name, its batch number and the fill-test result, in a technical report with a verification code.