Basement & foundation waterproofing for duplexes in Jazan

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

Why basement & foundation waterproofing differs in Jazan

Team note on Jazan: 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 Jazan sits about 7 m above sea level (SRTM open elevation data).

Jazan is about 1.9 km from the sea coast (OpenStreetMap).

The first thing checked on a duplex basement in Jazan is how close the structure sits to water, because the city's geography shapes what is likely to come through the walls. The centre of Jazan sits about 7 m above sea level, and the city is about 1.9 km from the sea coast. Both figures matter: a low, coastal-facing site can hold moisture in the ground and in the air, so the technician looks first at the lowest level of the building, the basement floor and the lower wall junctions, before deciding which system suits the job. Rates for basement waterproofing run SAR 50–150 per m², so the quoted scope should match the real wet area rather than a rough guess.

Several things are left to the site visit, because they cannot be known from a distance. The technician needs to walk the perimeter, look for active seepage, and find out where cracks run and how wide they are. Crack injection is priced at SAR 40–120 per metre, and whether a crack is a single hairline or a running fault changes the job completely. The same goes for the choice between epoxy coating at SAR 35–90 per m², spray foam at SAR 20–45 per m², and an XPS board system at SAR 12–30 per m². Only an inspection on the day can show whether the existing surface is sound enough to take a coating, and whether a bathroom above needs its own treatment at SAR 15–40 per m².

Information that helps the technician arrive ready is practical and worth gathering beforehand. Tell the crew the approximate basement area in square metres and the length of any visible cracks in metres, so the scope can be sized correctly. Mention whether the duplex has a water tank, since tank internal coating runs SAR 25–60 per m², and whether the flat roof needs liquid waterproofing at SAR 8–25 per m² or a bitumen membrane at SAR 15–35 per m². Note any past leaks, the months they occurred, and whether the ground outside has been built up or drains poorly. Clear access to the basement and the roof on the visit day lets the technician check everything in one trip.

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

When do you need basement & foundation waterproofing?

These are the signs most often linked to basement & foundation waterproofing:

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

Causes we see in the field

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

Tools and methods, and when we use them

How the work is done, step by step

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.

Quick comparison: facts and costs in Jazan

Questions from Jazan

Common mistakes we see

• 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.