Garry focuses on fully bonded or tackified modular products – with the purpose of highlighting common fitting requirements and best practise.

Easier to handle, flexibility in fitting, practical for raised access floors and offering infinite opportunities to mix and match designs; these are just some of the reasons why there continues to be huge shift towards modular flooring, such as LVT. Here, Garry Bateman, head of technical sales and support at Forbo Flooring Systems, focuses on fully bonded or tackified modular products – with the purpose of highlighting common fitting requirements and best practise.

‘Modular’ is the new term for tiles as it encompasses standard square tile sizes but also the new trend in rectangular planks and special shaped tiles such as Hungarian Point. They can be easily installed and removed.

As with all flooring, the appearance, performance and durability of the installed floorcovering will be determined to a large extent by the quality of the prepared subfloor and the conditions in which they are laid.

So, it is important to ensure that correct attention is given to provide a smooth, flat, level and sound substrate on which to fit any modular product in accordance with either BS8203:2017 for resilient flooring or BS5325:2001 for textile flooring. It is also important to follow any specific installation instructions provided by the manufacturer or supplier.

Surface regularity
British Standards refer to surface regularity and the need to ensure a floor is suitable for the use it is intended to perform. In 2019, the resilient flooring British Standard 8203:2017 added to the summary of the section on Surface Regularity as it was identified as a common marketplace issue that needed clarification. Section 6.2.3 in the standard has a useful commentary:

‘Surface irregularities can affect the overall visual appearance and wear life of the finished floor, resulting in prema-ture wear, localised soiling problems, loss of bond with the installation of tile products, particularly large format tiles and geometric designs, and potential difficulties with the installation of sheet floor coverings where site-formed cove skirting details are used.’

For the installer, the comments on loss of tile bond due to movement within the floor surface which can affect all types of tiles, both resilient and textile, is particularly relevant in large installations and when dealing with geometric floor layouts such as herringbone pattern planks. The problem is accentuated when unevenness is spasmodic throughout the installation leading to tiles running out of bond in all directions.

Raised access floors and conditioning
Raised access flooring panels can settle shortly after installation and this should be considered when assessing the appearance of the tile/plank installation fitted onto such flooring systems. Ridges between uneven raised access floor panels will telegraph through to the finished tile installation. Uneven or loose floor panels should be levelled or re-fixed before installing tiles or planks.

Note: unevenness between raised access floor panels will adversely affect the integrity of the adhesive bond and may cause tiles to de-bond, lift or move. Also, incidental low-level light will exaggerate any unevenness in the sub-floor. If any doubt exists, the raised access floor should be overlaid with plywood. For example, in accordance with BS8203:2017 for resilient products.

Prior to installation, the tiles and planks must be allowed to acclimatise in the laying area at a steady temperature of 18 to 27ºC for at least 24 hours. This is particularly important if the tiles have been stored or delivered in conditions of extreme temperature and/or humidity.

Always follow the specific guidance of the manufacturer/supplier regarding exact acclimatisation requirements for each product type as these will vary.

Production batches
As with any floor covering, the use of different production batches will always result in visible shade differences. It is essential that different batches of the same colour are not mixed in the same area. When ordering tiles, each floor area (plus spares) must be specified from the same batch.

Prior to installation, boxes should be checked to ensure that the correct tile type, colour, batch number and quantity have been received and that the tiles are in good condition. It is likely that no claim will be accepted for incorrect colour, pattern or obvious pre-installation damage if the tiles have been fitted.

Setting out and borders – resilient tiles and planks
The correct starting point for setting out a tiled floor is traditionally the centre of the area – although this may not be the final starting point when tile laying begins. Some adjustment of the starting point may be required, for example, to avoid small perimeter cuts, where the tiles are to be laid with a border, or with designs such as Hungarian Point. In corridors and small spaces, it may be simpler to work lengthwise from one end, using the centre line as a guide.

Begin laying tiles at the starting point, ensuring that the tile is laid exactly along the layout lines. If the first few tiles are not installed accurately, the entire installation will be affected. Lightly roll each row of planks with a hand roller to ensure a firm adhesive bond and remove any excess adhesive immediately.

Note: In a large area, two or more fitters may be placing tiles at the same time. As finger pressure in butting the tiles or planks together may be slightly different, best start from a common point and work away from it to avoid tiles or planks going out of bond.

In situations where the tiles or planks are being fully adhered, the time it takes to mark and cut the border tiles must be taken into consideration when planning the installation.

Without adequate planning, it is likely that the working time of the adhesive around the border tiles will be exceeded before the tiles are installed, which will result in an inadequate bond of the border tiles.

The successful installation of border tiles is best accomplished by following one of two strategies:
a) When laying out tile areas, determine the edge of a field tile a comfortable distance from each wall and then snap chalk lines around the perimeter of the room. Only spread adhesive up to this line for the field tiles installation. Spread adhesive and fit border tiles separately.
b) Plan the sequence of spreading adhesive so that the border tiles can be cut and placed into the adhesive before the adhesive working time has been exceeded.

Resilient and carpet tiles/planks together
A current trend is to install a mixture of resilient and carpet tile/planks together within the same area. This can be either as ‘islands of product’, such as breakout areas, or randomly mixed together across one area.

The main criteria here is to ensure that any height variation between the different products is accounted for in the subfloor preparation (if required) or planning. Avoidance of trip hazards is critical to ensure a safe transition be-tween individual areas or over the entire floor surface.

When it comes to stairs, appropriate stair nosings must be used for every tread. Tiles must be bonded securely to the stair tread using a permanent bond adhesive. Tiles to stair risers should be permanently bonded using a suitable contact adhesive.

Adhesives
Both full bond adhesives and tackifier adhesives must be spread evenly over the entire floor area with careful at-tention to edges – this will ensure any perimeter tile cuts are fully bonded. Failure to fully bond all full tiles and tile cuts may result in individual tiles shifting and lifting.

Note: where perimeter tiles are not constrained by fixtures, eg, walls, edge strips, etc, it is best practise that such tiles are adhered using a permanent adhesive.

Adhesives must be applied according to the manufacturer’s instructions and it is essential that tackifier adhesives are given time to dry to a clear, tacky finish before laying tiles. Failure to do so could result in a permanent non-release bond.

Note: the tackifier adhesive must be applied with a suitable short pile roller to ensure full contact of the tile backing with the adhesive.

Note: adhesive coverage rates will be reduced on very porous subfloors such as plywood or sand cement screeds. Highly absorbent subfloors such as sand/cement screeds and plywood etc. should be primed.

In closing, whilst this is not an exhaustive list of fitting requirements (these should always be sought from the relevant manufacturer or supplier), this article has tried to highlight some of the key elements to secure a satisfactory standard of installation which will both visually look good and endure for many years. The basic rules of engagement apply to fitting tiles or planks as to any floor covering: ensure subfloor preparation and installation techniques are in accordance with both the relevant British Standard or manufacturers/suppliers guidelines. Failure to do so may result in an unhappy customer and additional costs to rectify.