9 March 2022 - 16:43, by , in Waterproofing Membrane, No comments

Providing tailored quality repairs to leaking rooftop membranes


Our client inspected the roof of their building and discovered that the concrete roof needed a new waterproof membrane and that the perimeter joints needed to be repaired.

Water leaked into the warehouse through the deteriorating joint sealant and the waterproof membrane showed signs of deterioration. Additionally, during Singapore Waterproofings’ site inspection, our inspector found that there were some areas of pooling water due to inadequate drainage, which needed to be rectified.

Ensure effective drainage on flat rooftops by designing gradient falls to drains and floor wastes properly. A suitable fall creates flow paths that allow rainwater to flow efficiently to suitable discharge points as rapidly as possible, thereby reducing ponding.


Ponding water on flat roofs is one of the main causes of waterproof membrane deterioration because most membranes such as acrylic membranes are not designed to withstand pooling water. Standing water turns it into a muddy consistency when mixed with dust, plant matter and pollution and when the water has dried out, the crust contracts and puts the membrane under stress. Over time, this often causes the membrane to crack and peel – allowing water to leak through to the substrate.

As you can imagine, rooftop waterproof membranes are under continuous environmental stress; They are exposed to strong UV rays, rain, pollution, and salt if near the ocean, which can decrease the waterproofing membrane’s performance over time. The performance reduction can make the concrete and other building elements vulnerable to water ingress.

For reliable and long-lasting results, we select high-quality and fit-for-purpose waterproof membranes, as well as proper surface preparation, installation, and detailing.

On this roof we recommended the following cost-effective remedial waterproofing works to replace the existing waterproofing membrane and improve the fall to the drain/floor waste:

  1. Pressure clean existing waterproofing membrane
  2. Remove bottom of sheeting to allow detailing of waterproofing membrane to floor/wall joints
  3. Improve the gradient fall around the drain
  4. Install 2 coats of heavy-duty modified acrylic waterproofing membrane over 2 coats of moisture barrier primer system
  5. Install premium joint sealant to the perimeter of the rooftop
  6. Re-instate bottom wall sheeting


The existing waterproofing membrane was cleaned by pressure to remove dirt and grime and the bottom of the sheeting covering the edges was removed to gain access to the floor/wall joints. In order to ensure that rainwater effectively drains from the roof surface, our leak sealing specialist improved the gradient fall to the drain/floor waste.

Using a moisture barrier primer system detailed to the floor/wall joints, he installed heavy-duty modified acrylic waterproofing membrane. The perimeter of the rooftop was sprayed with a new premium joint sealant at the floor/wall joints.

2 coats of heavy-duty modified UV-stable acrylic waterproofing membrane system were installed over 2 coats of moisture barrier primer system and detailed to all penetrations and junctions followed by re-instating the bottom part of the wall sheeting. The waterproofing system will be supported by the manufacturer’s warranty for 15 years and extendable for a further 10 years with a maintenance application.

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