Roof waterproofing for apartments in Al Mrwj, Riyadh

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

Before we start: what we know about Al Mrwj

The centre of Al Mrwj is at 24.7578, 46.6637, about 5 km from the centre of Riyadh, with an approximate radius of 2.1 km. The approximate area shown on the map is centred here. Main roads in or near Al Mrwj: King Fahd Road, Northern Ring Road, King Abdulaziz Road.

The nearest wadi channel is about 2.8 km from the centre of Al Mrwj (OpenStreetMap). Al Mrwj has both villas and apartment buildings.

The centre of Al Mrwj sits about 635 m above sea level (SRTM open elevation data).

Roof leaks are the most common problem for apartment buildings in Al Mrwj, and they usually show up as damp patches on the top-floor ceiling, bubbling paint, or water running down internal walls after rain. On an apartment building the roof is shared, so a leak above one flat often affects several households, and small cracks in the roof surface or failed joints around water tanks and parapets are the usual starting points. Liquid roof waterproofing is typically priced at SAR 10–25 per m², while bitumen membrane sits at SAR 15–35 per m², so the chosen system should match the roof's condition rather than simply the lowest quote.

Al Mrwj sits at about 635 m above sea level, with its centre at 24.7578, 46.6637, roughly 5 km from the centre of Riyadh, and the nearest wadi channel lies about 2.8 km away. The location means rooftops and terraces are exposed to strong sun, heat cycling, and the occasional heavy downpour that drains quickly toward low ground. Because Al Mrwj has both villas and apartment buildings, the approach for an apartment roof must account for shared access, communal water tanks, and the drainage of several floors rather than a single house. Coatings that tolerate thermal movement, such as spray foam at SAR 20–45 per m² or a bitumen membrane, are often discussed for roofs that see large temperature swings, while crack injection at SAR 40–125 per metre suits isolated hairline defects. Bathroom waterproofing, at SAR 15–40 per m², is worth checking if the leak appears near a flat above a wet area.

Before the visit, ask the provider which system they recommend for your specific roof and why, and request a written scope that states the area in m², the materials, and whether the price covers surface preparation. Confirm who is responsible for access to the shared roof and whether the building management must approve the work in advance. Ask how drainage outlets, parapets, and tank bases will be treated, and whether any repairs to cracks will be measured separately per metre. Finally, ask how the work will be inspected and whether the warranty terms are provided in writing before any payment is made.

In apartment buildings, the floor below is often where a leak shows first.

Signs that call for roof waterproofing

These are the signs most often linked to roof waterproofing:

• The old waterproofing is cracking
• Stains on the top-floor ceiling after rain
• Water pooling on the roof

Where the problem usually comes from

• Cracks in the roof slab.
• Damaged waterproofing around tank and AC bases — we check this before anything else.
• Wrong falls towards the drains — we check this before anything else.

Tools and methods, and when we use them

The steps in order

1. Survey: Falls, drains and the condition of the old layer are recorded.
2. Preparation: Cleaning and repairs before any new layer.
3. Primer: The base coat that the system needs.
4. Waterproofing layers and details: Corners, upstands and bases get their own detail.
5. Flood test: The roof is flooded and checked before it is covered.

Quick comparison: facts and costs in Al Mrwj

Common questions about roof waterproofing in Al Mrwj

Common mistakes we see

• Covering the waterproofing before the flood test
• Ignoring the tank bases

What you receive

You receive: a quality record with photos and the flood-test result, in a technical report with a verification code.