Water tank waterproofing for duplexes in Aldawadmi

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

Before we start: what we know about Aldawadmi

The centre of Aldawadmi sits about 976 m above sea level (SRTM open elevation data). Main roads in or near Aldawadmi: King Abdulaziz Road, Dawadmi Bujadiyah Road.

Team note on Aldawadmi: 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 most common problem we see with water tanks on duplexes in Aldawadmi is slow leakage at the joints and cracks of the tank walls, which often goes unnoticed until the stored water tastes off or the wall below shows damp. Because a duplex usually shares one roof tank between two households, a leak affects both sides, and the owner of the upper unit is often the last to notice that the lower unit is the one getting wet. Our first step is therefore a full inspection of the tank interior and the roof surface above it, rather than simply recoating what looks worst.

Aldawadmi sits at about 976 m above sea level, which matters for the approach. Tanks here see strong daytime heat on the roof and a noticeable drop in temperature at night, so the expansion and contraction can open hairline cracks over time. For that reason we check whether the tank needs crack injection before any coating is applied, and we treat the roof separately. Liquid roof waterproofing is typically priced between SAR 8 and SAR 25 per m², bitumen membrane between SAR 15 and SAR 35 per m², and XPS boards between SAR 12 and SAR 30 per m², and the right choice depends on how the roof is used and how much sun it takes. Tank internal coating is priced between SAR 25 and SAR 60 per m², and it should only be applied once the cracks have been sealed and the surface is dry and clean.

Before the visit, ask the provider to confirm which surfaces they will measure, how the cracks will be located and sealed, and whether the price is quoted per square metre of the tank interior, the roof, or both. Ask whether the work covers only your unit or the shared tank serving both sides of the duplex, and who will coordinate with the neighbour. Ask how long the tank must stay empty after coating and how the water will be restored safely. A clear written scope, with each item priced against the local ranges above, makes it much easier to compare quotes and avoid surprises once the work begins.

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

Signs worth paying attention to

If you notice one of these signs in Aldawadmi, it is a good moment to talk to the team:

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

The most common causes

• A common cause: damaged old coating.
• Cracks in the walls or floor — we check this before anything else.
• A common cause: construction joints.

How we choose the tool in Aldawadmi

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.

Aldawadmi in facts and sources

Questions from Aldawadmi

What we advise against

• Using a material that is not intended for drinking water

What you receive

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.