Roof waterproofing for residential buildings in Unaizah

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

Before we start: what we know about Unaizah

The centre of Unaizah sits about 667 m above sea level (SRTM open elevation data). Team note on Unaizah: 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 centre of Unaizah sits about 667 m above sea level, which places the town on a plateau in the Qassim region rather than in the low desert basins. This elevation means the town sees a wider daily swing between warm afternoons and cooler nights than coastal cities do, and that temperature movement is hard on roof surfaces. Each day the membrane expands and contracts, and over years that repeated stress can open hairline gaps at joints and parapets. For residential roofs here, regular inspection of seams and edges matters as much as the initial installation.

Liquid roof waterproofing is priced at SAR 10–25 per m², and bitumen membrane at SAR 15–35 per m², while spray foam runs SAR 20–45 per m². Because the roof takes the full sun and the temperature swings described above, the choice of system should follow the condition of the surface. A liquid-applied layer suits a roof with many small irregularities, since it flows into corners and forms a seamless skin. A bitumen membrane gives a thicker, more uniform layer on flatter slabs. Insulation boards such as XPS, at SAR 10–30 per m², can be added beneath the waterproofing to slow heat transfer into the living space below. Crack injection, at SAR 40–115 per metre, is the right step when a fissure is found before a full recoat, because sealing the crack first prevents water from tracking beneath the new layer.

Owners often avoid several common errors when they plan this work. They do not coat over a damp or dusty surface, since moisture trapped beneath a new layer will lift it within months. They do not skip the edges, upstands and drainage outlets, where most leaks begin. They do not choose the cheapest per-metre rate without asking how the area was prepared and how many coats were applied. And they do not postpone repairs once a stain appears on the ceiling below, because water that has already entered the slab causes damage well beyond the roof itself. Planning around the local climate and the actual condition of the roof keeps the work effective for years.

For a whole building, a survey of the shared systems comes before unit-by-unit work.

When do you need roof waterproofing?

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

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

Causes we see in the field

• Damaged waterproofing around tank and AC bases — we check this before anything else.
• A common cause: wrong falls towards the drains.
• A common cause: cracks in the roof slab.

Tools and methods, and when we use them

From the first visit to the report

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.

Facts and costs — Unaizah

Short answers for Unaizah

What we advise against

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

What you get after the work

The written output: a quality record with photos and the flood-test result. The report is numbered and can be checked with its verification code.