Common Causes of Roof Water Leakage

Roof leaks can be frustrating because the point where water shows up indoors is not always where it is entering the roof. Knowing the common causes can help you describe the problem clearly when arranging an inspection.

Ageing or Damaged Waterproofing Layer

Most roofs rely on a waterproofing coating or membrane that gradually wears down from years of UV exposure and rain. Once this layer thins out or cracks, water can pass through even without any obvious structural damage.

Joints, Parapets and Penetrations

Roofs are rarely a single continuous surface — parapet walls, pipe outlets, vents and expansion joints all create points where water can enter if the seal has worn away or was not properly applied in the first place.

Poor Drainage

If a roof does not drain properly, water can sit for extended periods, increasing the chance it will find its way through any weak spot in the surface.

Structural Cracks

In some cases, cracks in the roof slab itself, rather than just the waterproofing coating, allow water through. These require crack repair in addition to a fresh waterproofing application.

How This Is Diagnosed

An inspection typically involves checking the roof surface, joints and penetrations, along with tracing indoor damp patches back to a likely source. Once the cause is identified, the repair process generally follows inspection, surface preparation, crack repair, waterproofing application, a protective top coat, and a final check.

If your roof shows signs of leakage, our roof waterproofing service covers this process from inspection through to completion.

Related: Roof · Crack Repair · Leakage Repair · Contact Us