Flat-out waterproofing success

Victoria Ramwell of Kemper System explains how liquid waterproofing solutions offer the long-term solutions that education buildings need for flat roofs, and the key considerations for specifiers

Whether as part of a refurbishment or new build, waterproofing flat roofs on educational buildings requires a highly durable, long-term solution. Ensuring the roof remains trouble-free for years to come is essential to keep occupiers in a safe and comfortable environment, and reduce future maintenance and costs.

Cold-applied liquid waterproofing solutions can tick all of these boxes, but also offer additional benefits for specifiers and end users alike.

The versatility of liquid systems means that most can be applied to roofs as well as balconies and walkways. They can also be used within a built-up roof system such as a green roof, making them ideal for educational establishments seeking to reduce their carbon footprint.

Quick curing times ensure the installation process is efficient, minimises disruption and helps keep the wider construction programme on track. As liquids are often roller applied with minimal equipment needed onsite, roof areas with lots of plant installed such as air conditioning units can also be easily waterproofed, as can more complex detailing.

For refurbishment projects, liquid waterproofing offers one of the safest solutions for educational sites which sometimes have to remain operational throughout the work. Quick to apply and with solvent-free options available, schools and universities can carry on as normal without having to worry about nuisance odours or fire risks.

Specification considerations
Liquids are the fastest growing sector of the flat roofing market, so there’s a vast range of products to choose from, but not all perform in the same way. This means specifiers must thoroughly research which system is most suitable for the application.

Consider the characteristics that will be needed to comply with Building Regulations and meet performance requirements such as the compatibility of the surfaces to be waterproofed, ability to withstand substrate movement, and resistance to damage from anticipated load levels or trafficking.

The manufacturer’s third-party accreditation, such as a BBA certificate, can assist with this process, but specifiers must thoroughly read the details in this document to check the liquid has been appropriately tested and is suitable for the application.

It is also important to establish whether a wet-on-wet or wet-on-dry liquid waterproofing system would be appropriate. When specified from a manufacturer with third-party accreditation, it should offer a durable waterproofing solution, but there are key differences to consider before specifying either one.

For example, when applying any liquid waterproofing product, it is often very difficult to achieve a consistent rate of coverage. This means that although the average membrane thickness may be as required, when the system begins to cure it could still be thin in parts, creating weak spots.

Specifying a wet-on-wet system with a reinforcement fleece makes it easier to obtain a consistent depth and coverage as the liquid system completely saturates the reinforcement layer. The resin then cures to form a single, fleece reinforced, chemically bonded membrane that is completely UV stable. This helps to avoid potential problems of inter-coat adhesion, thin spots or delamination.

Making the grade
As valuable, long-term assets, educational buildings demand waterproofing solutions that will stand the test of time. The versatility of liquids combined with their installation and performance benefits ensure the refurbishment and construction of flat roofs are delivered quickly, efficiently and to the highest standards.

Case study: The Stay Club
A new student accommodation complex in Camden, London, is benefitting from a liquid waterproofing solution. Constructed by Designated Contractors, ‘The Stay Club Kentish Town’ development comprises two buildings and 370 rooms. The majority of the scheme has been built using modular room pods.

The main contractor wanted an alternative to felt and which could accommodate complex detailing, so roofing contractors, Millgate Roofing Services, recommended a liquid waterproofing solution from Kemper System.

The cold-applied polyester-based system was installed across an area spanning around 3,000 m², including large flat roofs on each building. It was also used to waterproof 10 smaller roof areas at different levels; two green roofs, nine balconies, a podium between the two blocks, and a lift shaft.

Simon Barber, who was responsible for applying the waterproofing, said: “The two main roofs were relatively simple to waterproof, but the non-accessible smaller roofs and balconies featured a vast amount of detailing, so a liquid solution was essential.”