Water tank waterproofing for duplexes in Ahad Rafida

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

Water tank waterproofing in Ahad Rafida: the local context

Main roads in or near Ahad Rafida: King Khalid Road. The centre of Ahad Rafida sits about 2055 m above sea level (SRTM open elevation data).

Team note on Ahad Rafida: 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..

Ahad Rafida sits about 2055 m above sea level, which places it among the higher inhabited areas where residents see wide temperature swings between day and night. That elevation shapes how water tanks behave on duplex roofs: exposed rooftop tanks take in more direct sun during the day and lose heat quickly after dark, so the surface membrane and coating expand and contract more often. For owners, this means the waterproofing needs to tolerate repeated movement, not just a single dry-weather application.

Because of that movement, the practical focus for tanks here is on flexible, well-bonded systems and on inspecting the joints and seams where water is most likely to find a path. Tank internal coating is priced at SAR 25–60 per m², and a sound internal layer protects the stored water as well as the tank walls, which is worth keeping in mind for a household that relies on stored supply. Liquid roof waterproofing, at SAR 8–25 per m², and bitumen membrane, at SAR 15–35 per m², are commonly considered for the roof slab that carries the tank, while XPS boards, at SAR 12–30 per m², can help limit heat transfer into the space below. Each figure is a range that depends on the surface and the amount of work, so an on-site measurement is the basis for an accurate quote.

Owners in this area commonly avoid a few mistakes. They do not skip surface preparation, because coatings applied over dust, old paint or damp concrete lift off within a short period. They do not treat cracks as cosmetic: crack injection, priced at SAR 40–120 per metre, is far cheaper than repairing water damage in a duplex. They also avoid choosing a system only on the lowest unit price, since a thin or poorly bonded layer costs more once it has to be redone. Finally, they plan access to the tank before work starts, so the full surface can be reached and the coating allowed to cure properly before the tank is refilled.

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:

• 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 — we check this before anything else.
• A common cause: damaged old coating.
• Construction joints — we check this before anything else.

Tools and methods, and when we use them

The steps in order

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.

Quick comparison: facts and costs in Ahad Rafida

Questions from Ahad Rafida

What we advise against

• Using a material that is not intended for drinking water

What you receive

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