Within the flooring industry, we have all obtained knowledge by asking questions. On the flip side, if questions are not asked – or if they are perceived to be “silly questions” – then there’s potential to fail due to not making sure we have all the facts that lead us towards making an informed decision. This is especially important because there have been many changes in the industry, and I’m sure many more to come.
When I asked fellow industry professionals about the leading cause of flooring failure, their response was consistent across the board: the presence of moisture.
The aim of this technical advice column is not to explain moisture testing procedures, but rather to highlight the questions and resources that will guide us toward solutions.
Like other similar manufacturers, Bostik offers site inspections to investigate questions and provide hands-on training to help deliver answers. My day-to-day role involves attending various sites to test subfloor moisture levels. The flooring contractor typically calls with just one question: “Is the floor ready to be installed?”
Although this may sound funny, the best way for us to get a technical answer is to ask more questions, albeit from various parties, including but not limited to the flooring contractor, the main contractor, the specifiers, and other manufacturers involved, i.e., the substrate and underfloor heating (if incorporated) suppliers, and then the floor covering manufacturer themselves.
Apart from the relatively easy task of testing a subfloor that leads to a simple “Yes” or “No,” we need to start asking the following:
What is the specification of the substrate? This determines the manufacturer’s recommendations for appropriate test methods and provides in-depth information about the substrate’s make-up. Understanding these aspects helps us choose the best materials to use moving forward.
When was the substrate installed? The substrate needs to be installed for a certain amount of time before testing can be carried out. This duration varies, and the manufacturers can advise further on the curing requirements.
Does the substrate have any drying additives? While these will help reduce drying times, they don’t necessarily improve the substrate’s hardness. Additional information about the project would help us better understand the specific requirements.
Is the substrate hard enough? Scratch testing can be carried out in two forms: the Mohs hardness test and the ‘Ri-Ri’ scratch test. Both methods help determine surface hardness. The former uses minerals of known hardness to scratch the surface, while the latter uses a specialised tool to create intersecting grooves whose depth and delamination help to assess the hardness of the floor.
Is the building weathertight? Testing methods can be compromised and provide results that are not technically correct when weather conditions and the surroundings are affected.
Has the substrate been installed according to guidelines in a sealed, weathertight area? Substrates affected by rain are a commonly encountered issue!
Are the room’s conditions the same as where the flooring will ultimately be installed? Extreme temperature changes over short periods of time can significantly affect both the floor covering and the preparation materials, which need time to acclimatise.
Has the overall quality of the substrate installation been assessed? Some substrates require the room to be ventilated by opening doors and windows after 24-48 hours to aid the drying process.
Has underfloor heating been installed within the substrate? In my past articles, we looked at the effects of not commissioning the system and the adverse effects of only turning it on afterwards, including substrate curling, cracks within the base, delamination of applied products, thermal shock (expansion and/or contraction) leading to floor failures, softening of base material, blistering, and mould formation.
Is the subfloor level? – If the subfloor undulates significantly, it stands to reason that a lot more preparation is required. This additional work may not have been included in the original quotations.
Does the subfloor surface need attention? Before applying any further materials, assess the subfloor. A friable surface requires mechanical preparation to remove any contamination, i.e., plaster residue, which affects the overall preparation method.
Once the testing results are giving us the answers we need, the question is: what next? Applying a damp proof membrane no doubt creates a barrier that prevents moisture from affecting the adhesion of the flooring. But what about other parts of the building? Moisture will ultimately find its way out, so could the walls and other building fabric be affected? While surveyors who specialise in this department can provide answers, it’s important to raise these questions with the customer to make them aware of potential issues.
What’s next? The specified floor coverings will have specific adhesive requirements, and with today’s wider variety of flooring types, there is now a broader selection of adhesives to match.
Are there any other factors? Another overlooked factor is humidity: if the air in the building has a higher relative humidity level than the subfloor, the substrate is not going to dry naturally.
For the last question, from the main contractor’s point of view: “When the flooring contractor goes ahead with the installation, are they deemed to have accepted the status and condition of the floor?” Partner with a manufacturer that not only provides answers (and asks the right questions!), but also has the products needed to deliver the perfect finished installation.
