Providing tailored quality repairs to leaking rooftop membranes

When our client inspected their building’s roof, they identified that the concrete roof required a new waterproof membrane as well as the joint sealant refurbishment along the perimeter.

They noticed that the waterproof membrane showed signs of deterioration and that rainwater had leaked into the warehouse through the deteriorated joint sealant. Additionally, during Waterstop Solutions’ site inspection, our inspector identified there were some areas of pooling water due to inadequate falls to the drainage, which needed to be rectified.

Correct design specification of gradient falls to drains/floor waste is critical to ensure effective drainage on flat rooftops. Adequate falls create flow paths that direct the rainwater efficiently to suitable discharge points as rapidly as possible to help avoid ponding water.

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.

To achieve reliable and long-lasting solutions for our clients, we select high-quality and fit-for-purpose waterproof membranes combined with thorough surface preparation, correct 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

We pressure-cleaned the existing waterproofing membrane to remove the build-up of dirt and grime and removed the bottom of the sheeting covering the edges to allow access to the floor/wall joints. Our leak sealing specialist improved the gradient fall to the drain/floor waste to help ensure an effective discharge of rainwater from the roof surface.

After the removal of the existing joint sealant, he installed a heavy-duty modified acrylic waterproofing membrane to a moisture barrier primer system detailed to the floor/wall joints. A new premium joint sealant was installed to the floor/wall joints along the perimeter of the rooftop area.

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.