How do I deal with a leaky roof?

Leakage in buildings can be caused by age, natural disasters or engineering defects, with roofs, external walls and window edge being the most vulnerable. Here are some tips on how to prevent leaks. 

The building is exposed to the elements for many years or is shaken by earthquakes, which inevitably causes cracks and cracks, resulting in reduced waterproofing, indoor leaks and, over time, annoying wall cancer.

How to catch a leak

Whether water has accumulated on the roof

Check the roof surface after a rainy day. If there is water in the corners or localised areas, it means that the drainage slope is not properly sloped or the drainage holes are blocked and cannot drain smoothly; if water accumulates for a long period of time, it will cause the roof to leak due to infiltration.

Cracks in areas prone to water penetration

All areas of the roof should be carefully inspected; for example, underneath water towers, at the base of ventilation ducts, roof guttering, at drainage outlets and on garden planters, to see if cracks have developed that could cause rainwater to leak from the roof.

Check for peeling exterior tiles

If the exterior tiles are visibly peeling off, it means that the building is in disrepair and the waterproofing has failed due to heavy rainfall, earthquakes, etc. The chance of rainwater infiltration is increased.

Check for moss or plants

If moss or small plants are growing on the exterior walls, it means that the building is in a damp environment or that there is a serious water leak in the building itself, causing the walls to be damp and conducive to plant growth.

Look for watermarks, peeling paint or wall cracks

Watermarks on internal and external walls, stairwell walls and ceilings, as well as peeling paint and blackened walls, indicate a possible water leak.

If wall cracks is caused by an external wall problem, the leak is dealt with first before subsequent waterproofing work is carried out. The interior wall of the leaking area to the structural level is first chiselled away, with the chiselled surface as wide as possible, with the aim of enhancing the extent of the waterproofing treatment.

After the surface has been shaved until the red bricks are visible, cement mortar with water repellent is applied to fill the gaps to isolate the chance of external rainwater infiltration; a diluted flexible cement waterproofing coating is then applied to strengthen the waterproofing effect of the walls.