Richard Osborne, managing director at LTP, explains the reasons behind the rise of water-based sealers and the corresponding decline of traditional spirit-based products
It’s taken a while but we’re now seeing an inexorable march away from spirit-based sealers. There are several reasons for this and while some still prefer the finish provided by a “solvent”, the arguments for their use are, quite literally, being watered down.
In the tiling sector, the discussion centres on impregnating sealers and whether a water-based product can provide the same performance as a spirit. Spirit-based sealers contain a significantly higher level of organic solvents than water-based treatments. They create a strong odour that’s evident when a surface has been freshly sealed but, if incorrectly used, they can also be potentially hazardous and harmful to the environment.
The term solvent can be confusing because water itself is a solvent. Traditional sealers which are spirit or oil-based are often referred to as solvent-based, so it’s generally clearer to use the term spirit-based.
A spirit facilitates a sealer’s application, drying and the formation of an even seal below the surface of the tile or stone. During application and drying, it evaporates and releases volatile organic compounds (VOCs) into the atmosphere, so a fully cured sealed floor no longer contains spirit. To achieve an optimum seal with a spirit-based sealer, surfaces should be completely dry before application.
Historically, the molecules of the spirit carrier were smaller than water, so they tended to penetrate dense surfaces more quickly and more deeply, which in turn provided a higher quality seal. This, however, is no longer the case. Extensive research and development into water-based sealers, coupled with increasing withdrawals of solvent based raw materials, has created a breed of high-quality water-based sealers that are equal to or superior to their spirit-based equivalents. They offer excellent durability, quick drying times, an odourless application and they can be applied over residual moisture. Not all water-based sealers are completely spirit-free.
Many contain “co-solvents,” solvents present in lower concentrations that are meant to help push the rest of the water out of the coating as it dries. But since water-based solutions are either spirit-free, or contain considerably less, both provide a safer alternative to a traditional sealer.
Once applied and cured, water and spirit-based sealers function in a similar fashion. They are both tough and durable, they provide stain protection and are generally fully formulated and ready-to-use, so they’re easy to apply. One key difference is their appearance: spirit-based sealers tend to be clear as the sealer polymer and the spirit form a continuous clear solution, whereas some water-based sealers appear milky. This is because the polymers are present as separate particles and scatter visible light differently than the water in which they are dispersed. The milky appearance of a water-based sealer disappears as soon as the treatment cures.
In terms of environmental advantages, water-based products win hands down. Being low VOC and low odour, they’re less toxic, less harmful to the environment and to human health. This is especially relevant for internal projects, while a growing number of organisations now have sustainable maintenance policies in place relating to zero carbon and the use of toxic spirits. Less obvious benefits include easier transportation, handling and storage, as water-based products are non-hazardous and non-flammable. They also offer greater UV resistance; water-based sealers are fully transparent to UV light, so they do not undergo the photochemical breakdown experienced by some more UV-absorbent spirit-based sealers. And, as a general rule, water-based sealers tend to go further than solvent-based sealers, with a typical extra coverage of between 10 and 20% on most surfaces.
Within our own range, we now offer water-based equivalents alongside all of our traditional sealers. Whilst sales of water-based products continue to grow each year, spirit-based products still represent the majority of sales. This, however, is not likely to be the case for many more years.
Of course, the move towards water-based products isn’t completely conscience-based. There are other factors at play. Current economic uncertainties and the increasing cost of hydrocarbons are creating greater demand for water-based solutions. At the end of the day, price is always a big driver but, in this particular case, it’s creating a further wave of change.