How to choose mosaic grout

Learn why the colour of your grout makes all the difference

One of the things that surprised me most when I began working with mosaics is how big an impact the choice of grout can have upon the appearance of the finished piece.

Although there is an almost endless variety of mosaic tiles to choose from, you will probably already have a pretty good idea of your favourite colours and styles, which will narrow the choice down and simplify the process considerably. However, you may not yet have given much thought to the grout that goes between the tiles, and the two should really be discussed and decided simultaneously. Several standard colours are readily available, and mosaic grout can also be dyed to pretty much any colour using pigments. Your choice should be based not only on which colours you like, but more with respect to how it will interact with your chosen tiles to affect the overall appearance.

How to Choose Mosaic Grout

Surprisingly, up to a third of a mosaic item’s surface may actually be grout, so the first thing to consider is the overall effect you are looking for – in general, a dark grout will make for a darker piece and a light grout will lighten the whole piece. It sounds obvious, but it is an important point.

In the pictures below, I have used an identical formation of tiles on each slide, but used different grouts to illustrate the effect they each have.

As well as binding the tiles together physically and creating a smooth, unbroken surface, mosaic grout has the visual effect of holding similar colours together, and heightening the contrast of different colours. Using a darker grout will seem to unify a group of dark tiles into a single patch, but will make light tiles stand out. Lighter grout tends to emphasise the gaps between the tiles, which will highlight strong colours but can make pale tiles look a little washed out.

Of course, you want people to focus on the tiles rather than the grout, but with a little planning, it can be used to great effect, for example making a (light or colourful) feature stand out from a background by selecting a grout of a similar tone to the background. You can also use a grout that contrasts strongly with the mosaic tiles to accentuate a geometric pattern – forcing you to focus on it. Here’s a great little online tool that illustrates the above brilliantly.

Another consideration is where the piece will be used – outdoors, exposed to the elements, a light-coloured grout will stain, age and weather faster than dark, perhaps even turning green eventually. This may be the effect you’re seeking, but if not, I’d recommend a dark grey or black.

Selecting a grout that co-ordinates with your room’s paintwork, fabrics, or other furnishings can also be an effective way of making the finished piece look like it belongs in its surroundings.

It’s easy to commission your bespoke piece of mosaic furniture (mirrors, clocks, picture frames, plant pots…), and I will always work with you to understand your requirements and tastes, but I recommend thinking about these tips and pictures first as they may help you crystallise your ideas.