Water tank waterproofing for duplexes in Khulais

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

Water tank waterproofing in Khulais: the local context

The centre of Khulais sits about 94 m above sea level (SRTM open elevation data). Team note on Khulais: 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 Khulais sits about 94 m above sea level, which means the ground here is not a flood plain, but that does not remove the need for a proper seal on any tank that holds water through the year. On a duplex, the tank is usually the first thing a technician should check, because a leak inside a tank can run unseen into the slab and walls for months before anyone notices damp. Start by looking at the tank's internal surface, the seams, the inlet and outlet pipes, and the joint where the wall meets the base. Note any cracks, flaking old paint, or rust staining, since these tell you whether the existing coat has failed and how far the problem has spread. Tank internal coating is usually priced at SAR 25–60 per m², so measuring the internal area accurately at this stage helps the household understand the likely range before work begins.

Some things cannot be settled from the street or from a phone call and must be left to the site visit. The actual condition of the tank walls, whether the leak comes from the tank or from a pipe or fitting, the state of the roof above the tank, and whether there is moisture behind the bathroom tiles all need hands-on inspection. The technician should also decide which system fits the surface: epoxy coating (SAR 35–90 per m²), spray foam (SAR 20–45 per m²), or crack injection, which is charged per metre at SAR 40–120 per m when a crack is the only defect. Basement waterproofing (SAR 50–150 per m²) and bitumen membrane (SAR 15–35 per m²) apply only if the duplex has those elements, so confirm this on the visit rather than assuming.

To help the technician, the household should be ready with the age of the tank, the material it is built from, the date of any previous repair, and a clear note of when the leak was first noticed and whether it gets worse after rain or after the tank is filled. Photographs of the damp patches and the tank interior are useful. Let the technician know if the duplex is shared, because the tank may serve both units and the work will affect both households. Access to the roof and the bathrooms should be arranged in advance, and the water in the tank should be drained or kept low if the technician asks for it. Clear information at the start means a more accurate quote and a faster job.

In a duplex, the two floors often share lines, so tests are done floor by floor.

When do you need water tank waterproofing?

The following signs are worth checking before they grow:

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

Causes we see in the field

• A common cause: damaged old coating.
• Cracks in the walls or floor.
• Construction joints.

Tools and methods, and when we use them

How the work is done, step by step

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.

Facts and costs — Khulais

Short answers for Khulais

What we advise against

• Using a material that is not intended for drinking water

The written outputs

The written output: the material name, its batch number and the fill-test result. The report is numbered and can be checked with its verification code.