Understanding carpet tiles and ‘tackifiers’

Martin Cummins, UK technical support manager, Bostik.

THE design features of carpet tiles have come on leaps and bounds in recent years. No longer are they just hardwearing tiles in practical colours, but they now offer bespoke designs and different dimensions. From a designer and client’s viewpoint, the use of carpet tiles can result in a highly decorative and interesting flooring finish.

Of course, as with all floorcoverings, they may not always be the answer to the specific requirements of a project, but when they are, they offer some tangible benefits.

A major selling point is the ability to replace damaged or worn areas with fresh carpet tiles, or to introduce a variation in pattern without lifting the entire floor. Most other floorcoverings would need a full uplift and replacement. The reason this is possible for carpet tiles compared to all other permanently bonded flooring is twofold.

First, they’re designed to be very stable dimensionally. This means there won’t be any lipping or shrinkage at joints if installed correctly. Second, they should be designed to sit flat on the floor with no edge curl needing to be taken down. This means the requirements for bonding are significantly different from trying to bond, for example, a carpet roll or sheet vinyl, or indeed LVT tiles.

These products can have strong inherent curl, which requires a high-grab adhesive to hold it down, or they can be capable of shrinking or expanding, usually owing to temperature variations, so will need high-strength intimate bonding adhesives to hold them in place.

The bonding of carpet tiles doesn’t require this level of adhesion. In fact, the adhesives designed for use with carpet tiles, referred to as ‘carpet tile tackifiers’, are low-strength adhesives formulated to offer residual tack to stop carpet tiles sliding across the floor’s surface.

The tack is low enough to allow individual carpet tiles to be lifted up and replaced if desired. Of course, you have to put sufficient tackifier down to create this tack, so always follow the guidelines on coverage rates.

The standard method of applying carpet tile tackifier is by a roller. There are spray systems also available with pressurised canisters. Of course, application rate is not so easily regulated as when using a notched trowel, so don’t overstretch the product.

Normally, on an impervious subfloor where no adhesive soaks into the base, the coverage rate will be at its maximum. Always ensure the adhesive selection is suitable for the substrate – some adhesives may not contain rust inhibitors, which can be problematic if applying onto access panels. On very absorbent screeds it may sometimes be necessary to run a further coating if the initial one soaks in excessively.

There may be occasions where the carpet tiles need to be permanently bonded. This may be if using on treads on stairs, or areas of very heavy trafficking. In this case a tackifier is generally not the best option (although you can lay into wet for a greater adhesive strength).

Depending on the carpet tile backing, you would be better looking to an acrylic or pressure-sensitive system for all tiles including those that are PVC backed, or a carpet adhesive for non-PVC backed products.

If you find that the carpet tiles supplied have edge curl and don’t sit flat on the subfloor, then speak directly with the carpet tile manufacturers to see what their methodology for installation is. It may be a sign of tension in the tile backings and will mean the tiles will never sit flat and need a consideration for permanent bonding (somewhat negating their design).

One further benefit of carpet tiles is that the adhesive used to install them can be clean and easy to apply, totally solvent-free, phthalate- and propellant-free (unless canisters are used) and basically very consumer friendly. By using a BREEAM-rated adhesive, you can also improve your environmental profile.
01785 272625