In this article, Kelmore’s technical manager, Craig Powell, discusses the two types of levelling and smoothing compounds and their respective strengths and weaknesses.
In recent years, I have noticed the increasing popularity and more frequent use of two-part levelling and smoothing compounds within the tiling industry. Traditionally, there has been a clear distinction in the UK market – floor fitters have tended to prefer two-part products, while tilers have often leaned towards water-based alternatives. This preference among floor fitters likely arose from the amount of smoothing they undertake, and the convenience of using pre-gauged two-part products drove the trend. However, as I’ve highlighted in previous articles, the tiling industry is ever evolving. Today’s tilers are more aware than ever of the need to diversify their product list to address the complexities of modern projects.
This has led to a growing recognition of the advantages that two-part products can offer in certain situations. It’s important to note that choosing between these two types of products isn’t about one being inherently better than the other – such a decision is subjective. The choice can depend on practical factors, like the availability of a water supply on site or the need for consistent mixing ratios when working over large areas.
However, sometimes selecting the best option for the task at hand comes down to understanding the specific nuances of each product. Before diving into the differences between two-part and water-based products, let’s first examine the main criteria for selecting a particular levelling and smoothing compound.
These products are typically chosen based on a combination of factors, including their suitability for specific substrates, the required application depth, and the working, walk-on, and tile-on times that align with project demands. Additionally, a product with excellent flow characteristics and a superb surface finish is highly desirable.
For most applications, a product like LevelMore Flex&Fibre, Kelmore’s flexible, fibre reinforced compound that can be applied from 2mm to 50mm in a single layer, meets these criteria effectively. It offers excellent flow, dries with a fantastic surface finish, allows foot traffic after just 90 minutes, and is ready for tiling after only two hours.
Given the strong performance of such water-based products, one might wonder when a two-part product would be the better option. Beyond the convenience of a pre-gauged product, this is where nuances become important. For example, two-part products generally have lower compressive strength compared to their water-based counterparts. For instance, Flex&Fibre boasts a compressive strength of 25 N/sqmm , while LevelMore Pro, one of Kelmore’s two-part products, has a compressive strength of 16 N/sqmm. The softer nature of two-part compounds can be advantageous, as they tend to be more forgiving and generate less stress on the substrate. This characteristic is particularly important in certain scenarios.
For example, when working over existing adhesive residues, a compound with too much strength could pull the adhesive from the substrate. Similarly, flooring-grade asphalt or bitumen surfaces can vary in strength, which can be difficult to assess visually. Using a compound with a high compressive strength in such cases could lead to surface damage or even debonding. Therefore, opting for a softer compound in these instances would be a prudent choice. In conclusion, the choice between a two-part or water-based levelling and smoothing compound should be based on the specific requirements of the project.
By understanding the unique properties of each type, tilers can make informed decisions, ensuring the best possible outcomes for their work. At Kelmore, we offer three two-part and three water-based levelling and smoothing compounds, each with its own nuances to meet the diverse requirements of tilers and floor fitters.
www.kelmore.co.uk
