Roof waterproofing for duplexes in Najran

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

Why roof waterproofing differs in Najran

Team note on Najran: 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.. Main roads in or near Najran: Al Jarba Street.

The centre of Najran sits about 1309 m above sea level (SRTM open elevation data).

The centre of Najran sits about 1309 m above sea level (SRTM open elevation data), which means roofs here face a different climate pattern from coastal cities. Before quoting a duplex roof, the technician first checks the roof surface for existing ponding, lifted edges and old coatings, because the altitude and open exposure shape how fast a membrane ages under strong sun and sudden rain. Liquid roof waterproofing is typically priced at SAR 8–25 per m², while a bitumen membrane runs SAR 15–35 per m², so the first check is usually which system suits the roof condition and the owner's budget.

What is left to the site visit is the detail that no price list can settle. The technician measures the true roof area, marks the cracks and parapets, and decides whether a crack needs injection, which is priced at SAR 40–120 per metre, rather than a full new layer. The same visit confirms whether any shared stairwell, water tank or ground-floor wall is part of the job, since basement waterproofing is SAR 50–150 per m² and tank internal coating is SAR 25–60 per m², and those are separate scopes. Insulation under a new surface may also come up here, with XPS boards at SAR 12–30 per m², so the choice is made on the roof itself rather than from a catalogue.

Information that helps the technician is practical and worth gathering before the visit. Note the age of the existing coating, any previous repairs, where water has been seen inside the upper floor, and whether the roof is used for water storage or as a terrace. Photos taken after a rain show where water sits, which saves time. Tell the technician if the roof has been painted or tiled before, because that changes surface preparation. A clear list of these points lets the visit focus on the roof itself and gives you a more accurate estimate.

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

Signs that call for roof waterproofing

These are the signs most often linked to roof waterproofing:

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

The most common causes

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

Tools and methods, and when we use them

How the work is done, step by step

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 Najran

Common questions about roof waterproofing in Najran

Mistakes that cost more

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

The written outputs

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