Bitumen membrane for duplexes in Khafji

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

Before we start: what we know about Khafji

The centre of Khafji sits about 9 m above sea level (SRTM open elevation data). Khafji is about 2 km from the sea coast (OpenStreetMap).

Team note on Khafji: 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 Khafji: King Abdullah Road.

Consider a typical owner of a duplex in Khafji. They share a roof with a neighbour or manage a rooftop that gets full sun during the day, and they want to stop leaks before the rainy season without paying for work they do not need. Most owners in this position are weighing a single, clear solution for the roof rather than a patchwork of repairs, and they want a contractor who explains the scope in plain terms.

The local facts shape that choice. Khafji's centre sits about 9 m above sea level, and the town lies roughly 2 km from the coast, so the roof is exposed to salt-laden air and strong sun rather than sheltered inland conditions. For a duplex roof, a bitumen membrane is a sensible match: it is priced at SAR 15–35 per m², which sits in the middle of the range for roof systems, and it gives a continuous sheet that handles the heat and movement of a flat roof. Liquid roof waterproofing, at SAR 8–25 per m², is cheaper and can suit a small or simple area, but for a full duplex roof the owner should compare the two on total area and the condition of the existing surface.

Practical steps follow in order. First, walk the roof and mark every crack, blister and drain point, then price any crack repair as a separate line, since crack injection is charged at SAR 40–120 per metre. Second, confirm the roof area in square metres so the membrane quote is based on real measurements. Third, ask the contractor to clean and prime the surface before the membrane goes down, and to seal around parapets and drains. Fourth, if the top floor has a bathroom or a water tank, price those areas separately, because bathroom waterproofing runs at SAR 15–40 per m² and tank coating at SAR 25–60 per m². Finally, agree a written scope that names the membrane type, the area and the work to be done, so the owner can check the finished roof against what was agreed.

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

When do you need bitumen membrane?

These are the signs most often linked to bitumen membrane:

• A flat concrete roof that needs waterproofing
• Old rolls that are cracking

The most common causes

• No protection layer.
• Seams that were not welded properly.

Tools and methods, and when we use them

From the first visit to the report

1. Preparation: Cleaning, priming and repairs.
2. Torch welding: Overlaps are welded and checked.
3. Details: Upstands, drains and bases.
4. Protection and flood test: Protection is laid after a successful flood test.

Facts and costs — Khafji

Common questions about bitumen membrane in Khafji

Common mistakes we see

• Leaving the membrane exposed without protection

What you get after the work

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