Neil Sanders of F. Ball & Co explains the steps to ensure a flawless finish when installing this ever-popular choice of floorcovering.
The increasing quality and variety of luxury vinyl tiles (LVTs) and their suitability for a wide range of settings has seen their appeal continue to grow. Given the high expectations for such installations, ensuring a long-lasting, visually attractive flooring finish is essential when installing them. In line with BS 8203:2017 (Installation of resilient floor coverings – code of practice), this should involve following basic principles of subfloor preparation, as well as taking precautions to avoid common causes of floor failure. Selecting the optimum installation products at each stage of the process will also help.
The first step in any flooring installation should be to check that the subfloor is suitably sound, smooth and dry. To avoid costly floor failure, any laitance (fine particles appearing on the surface) and contaminants should be mechanically removed before installation.
Guarding against damp
At this stage, a moisture test should be conducted to determine if the subfloor is dry enough to receive floorcoverings. Excess subfloor moisture, whether residual construction moisture or rising damp, is the leading cause of floor failure, resulting in costly recalls and delays.
The only method of measuring subfloor relative humidity levels with certainty, and the method advocated by British Standards, is to use a calibrated hygrometer. Where subfloor relative humidity (RH) levels are higher than 75%, a moisture management solution will be required to prevent moisture attacking flooring adhesives and causing resilient floorcoverings to blister and lift.
Liquid waterproof surface membranes are available that will isolate excess subfloor moisture where relative humidity values are up to 98%, with a single coat application, and fully cure in as little as three hours.
Priming
In most cases it will be essential to prime a surface before applying a smoothing compound. This promotes the optimum performance characteristics of the smoothing compound and, when used over absorbent subfloors, such as concrete, prevents moisture being drawn from the smoothing compound, which will lead to a reduction in the working time. For time saving purposes, smoothing compounds are available
that can be applied directly over old adhesive residues without the need to prime beforehand.
General-purpose primers are available that can be used over both absorbent and non-absorbent surfaces. There are also specialist primers for use over non-absorbent surfaces, and primers designed for calcium sulphate screeds.
Creating a base
A smoothing compound should then be applied over the subfloor to create a perfectly smooth and level surface onto which LVTs can be installed. This ensures that the visual appearance of the floorcovering is flawless and not compromised by imperfections in the subfloor showing through.
In heavy-duty areas, where installations will be subject to heavy loads or high foot traffic, the use of an appropriate heavy-duty smoothing compound is recommended. The high compressive strength and excellent self-smoothing properties of these smoothing compounds will create the perfect base for the installation of LVTs.
When working over subfloors of plywood or steel, the application of a flexible smoothing compound is advised to accommodate movements in the subfloor and prevent cracking in the smoothing compound affecting the finished appearance of an installation.
Adhesive selection
Pressure-sensitive adhesives are often the best choice for installing vinyl tiles or planks. They form an instant grab upon contact, so contractors don’t need to worry about tiles or planks moving about when they are working, making them ideal for where intricate designs or patterns are being created.
It is important to remember that some adhesives require rolling with a paint roller that has been coated with the adhesive to flatten the ridges formed by application with certain kinds of trowel. This is to reduce the incidence of these trowel serrations shadowing through thin vinyl floorcoverings and affecting the appearance of the finished installation.
Compatibility check
Finally, it is highly recommended that contractors always check the compatibility of particular floorcoverings and adhesives. To do this, you can consult the floorcovering manufacturer’s guidelines or alternatively, F. Ball produces a Recommended Adhesives Guide (RAG), which lists adhesives recommended for use with over 6,000 floorcoverings produced by over 200 manufacturers.
Neil Sanders is technical director at F. Ball & Co. Ltd