Bostik’s construction solutions also include an extensive range of levelling compounds. Luc Wouters, business developer in floor technology for Belgium, is the ideal person to tell us about this range. Luc has over 34 years of experience at Bostik and spends his working days giving and offering advice for substrate preparation and training courses. Luc explains: ‘Floor technology includes all products for repairs to covering floors, damp screens, levelling agents, and wall and floor adhesives. Bostik has products for all phases of a project and suitably adapted materials.’

Ultra-high-speed is not always necessary
‘Analyse the base and the floor,’ is Luc’s first piece of advice. ‘The levelling compound used depends on the type of floor. Whether you fit ceramics, carpet, PVC, linoleum, or parquet, each floor has specific requirements which you have to consider.’

Features such as drying time, required layer thickness, strength, and flexibility have to be taken into account. And so, ultra-high-speed drying levelling compounds are not necessarily the ideal solution.

‘A completely flat base is a necessity with a flexible floor covering such as PVC or linoleum in order to achieve a tight result. Adhesives cannot level out any unevenness. With parquet, it’s a different story. A higher adhesive consumption, and therefore a thicker layer of adhesive, means you can eradicate unevenness. Moreover, with solid parquet, great compressive and tensile strength are essential because the wood continues to work into the base. And so, each installation needs the right leveller.’

As we’ve already said, the layer thickness is another requirement. Each levelling compound has its own maximum applicable layer thickness. Luc comments: ‘In practice, not every base is uniformly flat, so it can happen that in one corner you have to absorb 4mm, whilst you have a much greater difference in another corner. The Bostik levelling compound SL C940 XL (SL = Self-Levelling and C stands for cement-bound) even goes up to 5cm thick. The SL C780 FLEX is ideal for levelling a wooden base. This is a fibre-reinforced leveller with greater bend strength.’

The next piece of advice for professionals is always to respect the stated dose with water: ‘The last thing you want is a powdery end result. And so, you stick strictly to the prescribed quantity of water. Bostik always indicates these recommendations clearly on the pack.’

Look at the use
Originally, high-speed-drying levelling compounds were developed for application in retail and public areas where renovations have to be carried out quickly and efficiently. The closing time has to be kept to a minimum. Opting for a high-speed-drying levelling compound means that you can fit a new carpet or tile floor within two to four hours. The fastest-drying levelling compound from Bostik is the SL C990 SPRINTER. ‘Under perfect atmospheric conditions you can fit stone or carpet after barely two hours and a PVC floor such as LVT strips, for instance, after four hours.’

However, linoleum or parquet require a perfectly dry base. Both products are simply too sensitive to moisture. And so, it is recommended to wait 24 hours before you fit the floor, so there’s little point in using a high-speed-drying levelling agent.’

Developments and the environment
Finally, we consider innovations in the field of levellers. ‘On the market generally, but also especially at Bostik, lots of effort is made to offer ecological solutions. For instance, all our levelling compounds have at least one emission certificate, either EC1 or even EC1+. And so, they are absolutely ideal for use with green projects (BREEAM and LEED).’