Long gone are the days when the tiler only offered White, Off-white or Grey as the only colour options for grout. He would have a proprietary white wall grout and / or site mix local sand with the three colours of cement for floor grouting. If he was a stone fixer he might have added some pigment to keep some of the more demanding customers happy. Tiles were not as much a fashion item as they are today and choice of style and colour was very limited.
As tiles became more popular and competition drove the need to be different, fashion and colour became important characteristics to differentiate, excite and grow its usage. The rise in tile variety and colour has naturally driven a rise in the popularity of coloured grouts. This has seen many manufacturers produce and promote a myriad of grout colour palette’s to please the most discerning.
However this rise in popularity of coloured grouts by customers and designers has not been matched by any similar popularity with many tilers and stone fixers. For them it has meant coming to terms with seemingly more time consuming fixing practices and an even more demanding client, as almost any variation in colour is deemed unacceptable these days and the responsibility of the fixer or grout manufacturer. At times, even colour variation resulting from suspect grout selection practices. So what are some of the reasons for perceived or actual colour variation with cement grouts and how do we go about satisfying our consumer? Firstly, it has to be recognised grout colours shown on grout colour cards, chip clips, swatches, website and other tools are generally only colour replicas as accurate as the technology used, can reproduce. Absolute reliance on a colour selection made in a showroom with a coloured swatch and one or two tiles is generally always going to lead to disappointment.
Secondly, the effect that lighting can have on the appearance of a grout installation is profound. The angle of light, type of light, quality of light, and source of light all play key roles in how the grout will appear. It is not unusual for grout to appear as one colour during the day and as a different colour during the night. It is also not unusual for one batch of grout, used on both a floor and a wall to have different colour based on the angle of light hitting these surfaces. Wall washing lighting is especially notorious for creating drastic visual variations in grout appearance and I haven’t even started on how adjacent or background colours, like those of the tile, influence the perception of the grout colour. Significantly, as well affecting the actual tile / grout installation, this variation of colour or perception of colour difference can be just as profound at the time of colour grout selection – possibly resulting in an unsatisfactory colour grout choice.
Meaning, this design or selection and sampling process needs to be managed from the onset to deliver a realistic understanding of what to expect and ensure a satisfactory and known outcome. So after the selection process, verify actual appearance and compatibility with a test area on site before installing. It is really the only practical way to understand and overcome sample and lighting variation that will affect the final outcome. Next – Colour variation is inherent with any cement based grout. There are many variables which can affect the final colour of the grout and following are some of the areas the fixer needs to consider during the installation. Amount of water used in mixing – the use of too much water when mixing the grout can cause the grout to dry lighter than anticipated. Excess water dilutes the colour pigment concentration and will often cause the grout to be lighter in colour. Excessive amounts of water or any water based gauging liquid can also lead to the increased chance of efflorescence which invariably bonds to the surface causing the grout to look lighter in colour. Excessive or varying amounts of water to clean grout – The use of too much water during the cleanup process can wash out some of the colour pigments in the grout, also causing the grout to dry lighter than anticipated. Too much water used to clean the grout may also lead to efflorescence issues. Use a consistent amount of water in the sponge and clean the grout with the same techniques throughout the installation. Changing the cleaning water frequently will also help achieve the best results. Adhesive high in the joint – a common problem with grout being uneven in colour is the tile adhesive (often grey in colour) not being cleaned out of the joint during the tile or stone installation process. If the adhesive is left too high in the joint then a light or medium coloured grout may appear darker in colour than it should. The higher the adhesive is left in the joint, the darker the discolouration will appear. It is very important to ensure that any excess adhesive be removed from the joint during the installation of the tile or stone, or while the adhesive is still wet. Varying density of tile and stone can cause cement grouts to hydrate unevenly and thereby cause an inconsistent (blotchy) grout colour, upon drying. For example, a ceramic tile that has only two edges glazed, or a porous natural stone such as marble, can draw moisture from the cement grout, often times very quickly and differently. In some cases, the same batch of cement grout may potentially dry two different colours depending on the type of tile or stone around which it is installed due to varying absorption rates. Installations where different types of stone are used, or where tile and stone are used, may show variation in grout colour based solely on differences in tile absorption rates. The modern polymer modified grout performs far better with these conditions that the older standard unmodified types.
Type of substrate – the substrate over which tile or stone are installed can also play a significant part in the final colour of the cement grout. As an example: highly absorbent substrate. The moisture in the grout is drawn into the substrate which means that there is less water for the curing process of the grout. If the grout is not able to mature with the proper amount of water then the colour may very well be lighter than what is expected. To help prevent this from happening, it may be necessary to dampen (leave no standing water) with clean, potable water and a sponge over the tile installation just before grouting. This will add moisture to the substrate thereby lowering the absorption rate. Dampening the surface will also clean and cool the tile or stone. As always, it is best to conduct a test area whenever possible to verify results and confirm acceptability.
Using different manufacturers’ lot (batch) numbers in the same area, without dry blending all of the grout powder first, can cause the grout to appear different shades where the first batch of grout stops and the new batch(s) starts. When a different lot number (usually found on the bottom of the bags or above the bar code) is used, remember to mix them together dry in a clean container in order to maintain a consistent colour and always follow the manufacturer’s written instructions for mixing and slaking of cement grouts, prior to grouting.
Jobsite conditions – on many large jobs there are many factors which can have a significant effect on the installation of the grout. Exposure to wind, sunlight or other heat sources or any condition which can cause uneven drying may affect how the grout will appear when fully cured. For example, a grout job that is in direct sunlight can dry at a faster rate than an installation in a shaded area, thus causing a colour variation in the cement grout colour. A Portland cement based grout will appear darker in colour when it is wet, even after full cure, in the same way that a footpath appears darker in colour when it rains. Controlling jobsite conditions or protecting the grout from exposure to damage should be mandatory to prevent unsightly, contaminated grout.Following the manufacturer’s instructions and being mindful of the above should guarantee a good and consistent grout installation, and ensure that customer expectations regarding colour selection are met.
Credit: Tile Today magazine