Bitumen membrane in Allith: with a verifiable technical report

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

What is specific about Allith for bitumen membrane

Main roads in or near Allith: Al Laith Road, Amr Bin Al Aas Street. Allith is about 1.2 km from the sea coast (OpenStreetMap).

The centre of Allith sits about 5 m above sea level (SRTM open elevation data).

Bitumen membrane is one of the most widely used roof and foundation waterproofing systems, and the most common problem we see with it is failure at laps, edges and penetrations rather than in the open field of the membrane. Where the sheets have been overlapped poorly or the upstand at a parapet has not been sealed properly, water finds its way underneath and the membrane lifts over time. For a typical residential roof this means the owner notices damp patches on ceilings long after the original work was done, which is why the detailing around every edge matters as much as the sheet itself.

Allith sits about 5 m above sea level, which means the ground is low-lying and drainage can be slower after heavy rain, so standing water on a flat roof or a poorly graded surround is more likely to linger. The town is also about 1.2 km from the sea coast, so salt-laden air is a factor on exposed rooftops, and it can accelerate wear on surface finishes and fixings. Both facts push us to pay close attention to falls, outlets and the condition of any protective topping. A membrane that is well laid but sitting in a shallow depression will hold water against its seams, so the approach here starts with checking how the roof actually drains before any new material goes down.

Before the visit, ask whether the surveyor will check roof falls, outlets and the condition of every upstand, and whether they will look at the lap joints and penetrations, not just the main roof area. Ask how the existing membrane is being assessed, whether the work will be priced per square metre of bitumen membrane (SAR 15–35 per m²) or includes additional detailing, and what the scope will cover at the edges. It is also reasonable to ask for a written technical report setting out what was found, what is recommended and why, so that you have a record to refer back to whatever the outcome.

Each job ends with a written report that carries a verification code you can check on our site.

Signs worth paying attention to

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

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

Causes we see in the field

• Seams that were not welded properly.
• No protection layer — we check this before anything else.

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.

Allith in facts and sources

Questions from Allith

What we advise against

• Leaving the membrane exposed without protection

What you receive

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