Be aware of false claims about odour and liquid applied waterproofing systems

The recent rise in popularity of liquid applied waterproofing systems for flat roofs, balconies and walkways has been coupled with a rise in confusion and misinformation surrounding the odours they emit. Alex Coward of Sika, explains the facts about the components of these roofing systems, the possible misinterpretation of odour and how to ensure you’re choosing a truly low odour product, if this is a requirement for your specification

The growth of liquid applied roofing solutions
Many specifiers now hold a preference for liquid applied waterproofing coatings, in fact they are one of the fastest growing segments in the roofing market, explains Alex. This is thanks to their versatility and workability when it comes to application – they’re perfect for complex roof designs and areas with tricky detailing – as well as being cold applied to help manage risk. The seamless finish of these liquid coatings not only creates a durable weather resistant waterproofing solution that lasts long term, it’s also aesthetically pleasing. A win-win for architects and clients.

The issue of unfamiliar odour
The high performance of these modern liquid applied systems is engineered in the lab and relies on clever chemistry, which we are constantly evolving. But, as these coatings are often solvent based, one of the main challenges relating to their use is the odour emitted during and for a period after application, which is a consequence of the product’s drying and curing processes. This is especially the case during refurbishment projects, where the presence of building occupants can sometimes result in concerns over unfamiliar odours, which people tend to incorrectly associate with hazard. These complaints have to be dealt with by the contractor and client, but more often than not make their way back to the specifier and inevitably the manufacturer to comment on.

You can’t tell much from odour alone
However, it’s important to be aware that, odour cannot always be taken as a reliable indicator of hazards associated with a product or its constituents. Some chemicals have no odour at all, but can still provide potential for a hazardous working environment, whereas other products with a heavy odour, can, in some instances, be completely innocuous.

At Sika, we have worked hard to undertake workplace exposure testing to demonstrate the safe working environment during and after application for all our systems and products. But we know that it’s difficult to educate the general public about this and sometimes it’s easier to choose a low odour product that has the potential to be less disruptive during application, especially in sensitive environments such as schools, hospitals, food processing facilities and social housing.

How to choose a truly low odour system
Many manufacturers have responded to this requirement by launching products to market that claim to be low odour or even no odour (which is almost impossible to achieve). Yet these claims are completely subjective, so finding the right low odour waterproofing system for a roof, balcony or walkway can be a bit of a minefield. For example, in some instances, instead of tackling the issue of odour by engineering it out from the start, some manufacturers are adopting a masking approach in order to replace unfamiliar odours with a more familiar and pleasant one.

It’s important that architects stay alert to low or no odour claims. The best way to do this is to work with a manufacturer that you trust, one that has a proven track record and can provide you with data and third-party verification about odour and emissions.

The stamp to look out for in this instance is Olfasense UK (formerly Odournet UK). With over 30 years’ experience, the organisation offers an independent, comparative, sensory analysis service. Products tested by Olfasense inevitably helps to provide confidence around low odour claims.

Taking responsibility as manufacturers
Sika is currently the only manufacturer to hold this independent verification for this type of roofing technology, and we hope others will follow suit. This dedication to clarity is more important than ever in recent years. Manufacturers have an obligation to be wholly accurate around system performance claims with independent verification where possible.

Research and development is key
It’s thanks to our state-of-the-art Global Technology Centre and chemical manufacturing plant, based here in Preston, that we are able to stay on the front foot and develop products that are better for people and the planet. We have unique access to an expert research team that can source and hybridise innovative solvents, giving our customers the benefit of progressive building products and systems. It means we can respond quickly when there is a need in the market or a regulatory change and we are always working on updating and improving our systems.

Our aim is to give specifiers the option of roofing systems with low odour and by engineering it out at an early stage, we ensure that our roofing products are truly low odour while still maintaining, and even improving, their performance in terms of durability and workability. This means when you choose a low odour product, you don’t have to compromise.

Alex Coward is head of technical – roofing & flooring at Sika
Sika provides three distinct roofing solutions for its customers: single ply membranes, liquid applied membranes and bituminous membranes from its leading brands – Sika Sarnafil, Sika Liquid Plastics, SikaBit and Sika-Trocal. For more information about Sika’s products and services call 01707 394444, email enquiries(Replace this parenthesis with the @ sign) or visit