Levelling compounds are used to make an uneven substrate sufficiently level to enable the application of the final floor. Since the levelling compound is beneath the flooring, you might wonder what it has to do with the indoor environment? Quite a lot in fact.

There has been much discussion about the indoor environment.. It has been found that in many buildings, some people have health complaints that can be related to the building itself. The health problems are referred to as "sick building syndrome" (SBS), but it is clear that there is no single cause for the problems. In fact, very little is known about the medical mechanisms behind SBS. The aim, therefore, has been a search for statistical evidence to point to probable causes. Through this work, excessive moisture has emerged as one of the possible culprits.

Levelling compounds can have a considerable influence on the indoor environment. The use of casein-containing products in Scandinavia around the 1980's caused widespread health problems; the so-called "sick building syndrome" (SBS).

In order to reduce the likelihood of a levelling compound contributing to pollution of the indoor environment, choose a product that is labelled both with the Finnish M 1 classification and the German EMICODE EC 1. Both of these limit product primary emissions.

In order to minimize the risk of secondary emissions from alkali attack on adhesives and flooring, the product should meet class AN 1 according to the industry protocol of the Swedish Flooring Trade Association. Further, information should be sought if the critical relative humidity is higher than 85% RH (CM > 2%). Such information should be supported by long-term testing of secondary emissions.

Levelling compounds that fulfil these criteria can be said not only to have a minimal adverse effect on the indoor environment, but to actually have a positive impact, as they provide a protective layer beneath the flooring, reducing the risk of secondary emissions from the concrete.