Basement & foundation waterproofing for duplexes in Alhait

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

Before we start: what we know about Alhait

The centre of Alhait sits about 980 m above sea level (SRTM open elevation data).

Alhait sits at roughly 980 metres above sea level, according to SRTM open elevation data, which means the town is set on higher ground than most coastal parts of the Kingdom. For basement and foundation work on duplexes, that elevation shapes how water behaves around a building. Rain runs off slopes quickly, but it also gathers in low corners, along retaining walls, and where driveways drain toward the house. Our crews begin each job by tracing how surface water moves across the plot before deciding where the waterproofing needs to start.

The practical effect is that most leaks we treat in Alhait come from water pressing against the outer walls after heavy rain, not from rising groundwater. That is why the work often combines a bitumen membrane on the external face of the basement wall, priced at SAR 15–35 per m², with XPS boards to protect the membrane during backfilling. Where cracks have already opened, crack injection at SAR 40–120 per metre seals the path water is taking. For the internal faces of a basement, epoxy coating at SAR 35–90 per m² or spray foam at SAR 20–45 per m² gives a second line of defence, and basement waterproofing itself is quoted at SAR 50–150 per m² depending on access and wall condition.

Duplex owners in Alhait often make the same mistakes, and most can be avoided with a simple check before work starts. The first is sealing the inside of a wall while ignoring the outside, which only moves the damp to a new place. The second is letting soil or paving sit against the wall right after waterproofing, which tears the membrane. The third is leaving drainage outlets blocked, so the water we redirect has nowhere to go. The fourth is treating a bathroom or roof as separate from the foundation, when a leak above can look like a basement problem. Planning these details together keeps the work effective and the money well spent.

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

Signs worth paying attention to

The following signs are worth checking before they grow:

• Water seeping in after rain
• Salt marks at the bottom of the walls
• Damp basement walls

Causes we see in the field

• A common cause: cracks at construction joints.
• A common cause: a high groundwater level.
• A common cause: rainwater draining towards the foundation.

Tools we use in Alhait

The steps in order

1. Finding the source: Groundwater, rain or a pipe — each needs a different treatment.
2. Preparation: Surfaces are cleaned and opened where needed.
3. Injection: Active cracks are injected.
4. Waterproofing layers: The system is applied on the right side of the wall where possible.
5. Follow-up: Readings are repeated after the treatment.

Facts and costs — Alhait

Questions from Alhait

Mistakes that cost more

• Painting the basement wall while the water comes from outside

What you receive

You receive: the source, the treatment and the follow-up result, in a technical report with a verification code.