Stewart goes into detail about the importance of ensuring you have the right adhesives.

Choosing the correct adhesive when installing LVTs can be influenced by various factors, all of which need to be taken into consideration by the contractor and installer, to ensure the correct adhesive selection is made. These factors will include location, usage and the environment of a building.

Over the past few years, the use of underfloor heating has become more prevalent in domestic and contract projects, with traditional in-screed systems and proprietary piped water and electric systems being widely installed. There are also more buildings where floor-to-ceiling windows, large bi-fold doors and large roof lanterns are being installed, which, owing to the potential for solar gain, must be taken into consideration when selecting the type of adhesive required.

Adhesive selection will also need be considered in terms of meeting specific site requirements regarding working times, design parameters and where faster installation times are required owing to onsite programme constraints. Another important factor when choosing an adhesive is it’s environmentally and, importantly, user friendly for the installer, with very low levels of VOc’s. Adhesives are stringently tested to comply to the strictest health and environment requirements set out by the GEV Emicode and Blue Angel. With all adhesive specifications, performance, assurance, application methods and health in the environment must always be considered by the contractors and installers.

When installing LVTs, various adhesive designs and formulations can be used to bond the material. These include dispersion adhesives, reactive adhesives and silane adhesives. These formulations will allow easy application by installers, enabling the completion of a successful flooring installation.

Pressure sensitive adhesives allow for LVTs to be installed once the adhesive has been allowed to dry, in a set open time, obtaining instant grab upon positioning of the LVT. This enables the installer to traffic the areas as soon as the materials are installed. Some adhesives can also be used as transitional pressure sensitive and are also suitable as a wet lay adhesive on floors that have an absorbent surface. The application of a pressure sensitive adhesive can be carried out by trowel or by trowel and roller, which will eliminate all trowel serrations and adhesive crenelations.

High temperature adhesives allow for the installation of LVTs in areas where temperatures will fluctuate, where underfloor heating is installed and in areas of non-extreme solar gain. Normal installation practice when using high temperature adhesive is to allow for very little open time and, when placing the LVTs into the wet adhesive, ensuring full compression of the adhesive. The high temperature adhesives can also benefit from the inclusion of fibres within, which give the LVTs a high dimension stability.

Reactive adhesives are made up from epoxies and polyurethanes and come as a two-component unit, resin and hardening catalyst. When units are mixed together the adhesive cures through an exothermic chemical reaction. They can be applied in areas where there are excessive changes in temperatures, wet areas and in areas subject to high mechanical loads. When installing LVTs into reactive adhesives they must be laid and positioned into the adhesive while it’s wet. The areas must not then be trafficked until the adhesive has fully cured as no repositioning of the LVTs can be made.

Silane adhesives are more of a universal product that can be used for installing LVTs in various types of locations, including environments with changing temperatures, heavy foot fall, and areas subject to water from above in all domestic and commercial locations. Silane adhesives are single component products, so no mixing of a hardener is required prior to its application. The LVT flooring is installed into the wet adhesive, compressing all trowel ridges and ensuring a good adhesive transfer which creates a strong bond of the applied material.

When the adhesive choice has been made, it’s important to follow the manufacturer’s instructions to guarantee a successful and problem-free installation. Site conditions must be monitored so floor temperatures, air temperatures and humidity levels are maintained during and after installation of the LVTs. The correct adhesive trowel notch must be selected so the correct amount of adhesive is applied to the substrate prior to the fitting of the LVTs. Advice from the manufacturers must always be sought to confirm the compatibility of the product to be used and the adhesive selection.
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Stewart Plant is technical manager, resilient at Mapei UK