Bitumen membrane for duplexes in Aljumum

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

Why bitumen membrane differs in Aljumum

Team note on Aljumum: 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 Aljumum sits about 200 m above sea level (SRTM open elevation data).

Aljumum sits about 200 m above sea level, a fact that shapes how water behaves on a site here. Rain runs off sloped ground and roofs quickly, and on higher ground water tends to move toward lower corners and boundary walls rather than pooling in one place. For a bitumen membrane on a duplex, this means the roof and the upper edges of the structure take the most direct exposure, so the membrane needs to be laid with proper falls and carried neatly up parapets and upstands. Owners should expect the work to focus on drainage paths as much as on the flat surface itself.

Each feature of the area leads to a practical choice in the service. Because the terrain drains quickly, the installer checks outlets, gutters and the line of each fall before the membrane goes down, so that water leaves the roof instead of sitting on it. Bitumen membrane is priced at SAR 15–35 per m², and the final figure depends on the roof area, the number of penetrations and the detailing around edges. Where a duplex roof has several levels or plant upstands, the detailing takes longer, and the quote should reflect that rather than a flat rate. Where a roof is shared between two units, both owners should agree the scope and the access arrangements before work starts.

Owners in Aljumum often make the same few mistakes, and the service is designed to avoid them. The first is laying the membrane over a surface that still holds moisture or loose debris, which stops the bond from forming properly. The second is leaving edges and corners unsealed, since water finds these weak points first. The third is treating the roof alone and ignoring cracks in nearby walls, which can be repaired with crack injection at SAR 40–120 per metre when they are found early. Checking these points before the membrane is laid saves repeat work later and keeps the duplex dry through the seasons.

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

Signs worth paying attention to

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

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

The most common causes

• A common cause: seams that were not welded properly.
• No protection layer.

Tools and methods, and when we use them

How the work is done, step by step

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 — Aljumum

Common questions about bitumen membrane in Aljumum

What we advise against

• Leaving the membrane exposed without protection

The written outputs

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