Hot Spot – a significant problem for LVT flooring

Flooring installed in sunny areas is subject to large temperature changes caused by heating through direct sunlight falling on the floor surface. These temperature changes often reach tens of degrees of difference over the course of a single day – during the day the floor surface can reach temperatures of more than 50 degrees, while at night its temperature drops below 20 degrees.

Any material modify its volume during temperature changes. This phenomenon also applies to floors. Since LVT floors are flexible, they are also more susceptible to deformation. When temperatures rise, LVT panels expand their volume and it translates into an increase in the size of individual panels. In extreme situations, when the increase in size is so large that the floor no longer has room to expand at the wall and separation expansion joints, the floor panels can lift and deform. If such deformation is long enough, it can cause permanent dimensional changes in individual panels. In this situation, the reverse phenomenon, i.e. shrinkage due to a drop in temperature can result in the appearance of gaps between the panels and even damage to the locks which as we know in the case of LVT floors are a sensitive component of the flooring system. Damaged locks lead to the perpetuation of inconsistencies in the floor covering and aesthetically unacceptable changes in the form of gaps and unevenness. Such deformations are called the Hot Spot effect.

The MMFA (Multilayer Modular Flooring Association) organization of which we are a member has launched a standardization and research project aimed at introducing an additional division of vinyl floors based on their susceptibility or resistance to the Hot Spot effect. At this year’s MMFA conference to celebrate the organization’s 10th anniversary, we had the opportunity to review a report summarizing the draft method for testing the Hot Spot effect for LVT flooring. It was developed by the EPH research institute in Dresden with which we are pleased to cooperate. Currently we are in the final stages of standardization implementation.

Currently in the absence of regulation and formalized testing methods it is not easy to avoid the negative effects of strong sunlight on vinyl flooring.

Installers and users should therefore pay attention to two aspects:

1. The floor manufacturer’s declarations regarding the dimensional stability of LVT panels under the influence of changing temperatures – if the manufacturer mentions this it means that it is aware of the problem and will indicate to us products with the required dimensional stability
2. Selection of the right flooring underlay – because the Hot Spot effect is intensified when using so-called heat blockers, i.e. insulating materials such as XPS, poorly heat-conducting materials such as PE foams, woodfibre or natural cork. For optimal heat conduction which will allow excess heat to be dissipated directly into the floor only two types of underlay materials can be recommended: natural rubber and PU (polyurethane). Both have absolutely unrivaled thermal conductivity properties. In addition natural rubber has excellent soundproofing properties which puts this material in the line of first choice for LVT floors installed in sunny areas.

Flooring underlay manufacturers today strongly favor products of natural origin, free of hazardous compounds or recycled raw materials. For this reason underlays such as RWS Barrier from the Extreme line produced by Fair Underlay are the best option because in addition to their excellent properties their composition is made up of more than 98% naturally derived components:

– natural rubber,

– mineral chalk,

– mineral, untreated oil.