Water tank waterproofing for duplexes in Al Aryja, Riyadh

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

Water tank waterproofing in Al Aryja: the local context

The centre of Al Aryja is at 24.6257, 46.6566, about 10 km from the centre of Riyadh, with an approximate radius of 2 km. The service-area circle on the map below is drawn from this point. Main roads in or near Al Aryja: Yazid bin Abi Sufyan Road, Imam Abu Hanifa Road, Prince Fahd bin Faisal bin Farhan Al Saud Road.

The centre of Al Aryja sits about 629 m above sea level (SRTM open elevation data). The nearest wadi channel is about 0.3 km from the centre of Al Aryja (OpenStreetMap).

An owner of a duplex in Al Aryja usually lives with a rooftop water tank that has been in service for years, and may only think about it when a stain appears on a ceiling or the water starts to taste or look wrong. Duplex owners often share the roof or the tank with a neighbour, so a repair can feel like a shared problem with unclear responsibility. The tank is out of sight, and the leak may run for months before anyone notices it inside the living space below.

Al Aryja sits at about 629 m above sea level, roughly 10 km from the centre of Riyadh, and its centre lies at 24.6257, 46.6566. The nearest wadi channel is about 0.3 km from the centre, which matters because heavy rain can run off quickly and load the walls and base of nearby structures. Because the wadi is so close, a tank that has already started to seep is more exposed to moisture working its way into the structure. For a duplex, this means waterproofing work should be checked early, before damp spreads into the shared slab and the upper and lower units both suffer.

A sensible sequence starts with an inspection of the tank walls, base and lid, and of any cracks in the roof slab beneath it. Next, cracks should be sealed by crack injection, which is priced at SAR 40–125 per metre, and the internal surface should be treated with a tank internal coating at SAR 25–65 per m². Where the roof around the tank is exposed, liquid roof waterproofing at SAR 10–25 per m² or a bitumen membrane at SAR 15–35 per m² can protect the slab. Finally, agree with the other owner in writing who pays for which part, and keep the receipts and the date of each job so the next inspection has a clear record.

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

Signs worth paying attention to

These are the signs most often linked to water tank waterproofing:

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

Where the problem usually comes from

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

Tools and methods, and when we use them

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.

Facts and costs — Al Aryja

Short answers for Al Aryja

Common mistakes we see

• 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.