What Grout Should You Use with Finger and Kit Kat Mosaics?

01 September 2026 · Tile Touch

Short answer: for most finger and kit kat mosaics, an unsanded cement grout suits the narrow joints, while an epoxy grout is worth the extra effort in wet or high-traffic areas. The grout colour you pick will change how the whole wall reads, so it deserves as much thought as the tile itself. Here is how to decide.

Why grout choice matters more with mosaics

Mosaics have far more grout lines per square metre than a large-format tile. On a kit kat finger mosaic like the Gracemere Bone White Speckle Gloss Concave Kit Kat Finger Mosaic Tile, or a fishscale sheet like the Wellwood Water Green Gloss Fishscale Mosaic, the joints are a big part of what you see. Get the grout right and the pattern sings. Get it wrong and the wall looks busy or muddy.

Because the joints are so visible, two things matter: the type of grout (how it performs and how fine a joint it fills) and the colour (how much contrast you want between tile and joint).

Sanded or unsanded grout?

The rule of thumb is based on joint width. Finger and kit kat mosaics are usually set with narrow joints, often around 1.5 to 2 mm. Narrow joints call for an unsanded grout, which is smoother and packs neatly into a fine gap without the risk of scratching a glossy glaze.

Sanded grout is designed for wider joints, roughly 3 mm and up, where the sand adds body and helps resist cracking. If you are laying a mosaic with wider spacing, or a larger-format hex such as the Lucas Large Black Matt Hexagon Mosaic, check the joint you are actually setting and match the grout to it. When in doubt, follow the grout manufacturer's stated joint range.

One caution with glossy finishes: gritty sanded grout can dull or micro-scratch a high-gloss glaze during clean-up. On gloss mosaics like the Anzac Gloss Ocean Blue Square Mosaic or the Fairway Small Plain White Gloss Square Mosaic 48x48mm, an unsanded or a smooth epoxy grout is the safer choice.

When epoxy grout is worth it

Epoxy grout costs more and is harder to work with than cement grout, but it earns its place in the wettest spots. It resists water, stains and most household chemicals, and it does not need sealing. That makes it a strong option for shower walls, splashbacks behind the stove and anywhere that sees constant moisture or grease.

For a kitchen splashback, a fishscale feature such as the Wellwood Black Gloss Fishscale Mosaic, or a penny round like the Vogue Gold Matt Penny Round Mosaic, epoxy holds its colour and shrugs off cooking splatter. If the mosaic is going somewhere dry, like a feature wall or a low-traffic hallway, a good cement grout is usually enough.

Choosing grout colour

Colour is where you set the mood. You have three broad options.

Match the tile. A grout close to the tile colour makes the surface read as one soft field and quietens the pattern. A pale grout with a white mosaic such as the Lucas Mini White Gloss Hexagon Mosaic or the Lucas Large White Matt Hexagon Mosaic keeps things calm.
Contrast the tile. A darker or lighter grout draws every joint, so the shape of each piece stands out. This suits geometric mosaics and hex patterns where you want to see the outline.
Go tonal. A grout a shade off the tile splits the difference: the pattern shows without shouting. A soft grey with a green fishscale like the Wellwood Jade Green Fishscale Mosaic reads gently rather than stark.

A tip worth remembering: light grout in a floor or splashback shows dirt sooner and needs more upkeep, while a mid-tone hides everyday marks better.

Grout and different mosaic shapes

The shape of the tile changes how the grout behaves. Concave kit kat fingers have a curved face, so grout sits below the high points of the tile and the fingers catch the light. Fishscale and penny round shapes create curved joints that a smooth unsanded or epoxy grout fills more tidily than a coarse sanded one. Cube and square mosaics like the Hennessy Carrara Marble Look Cube Matt Ceramic Mosaic give you straight, even joints, so any small colour mismatch is easy to spot; mix your grout consistently and don't run out mid-wall.

A simple way to decide

Measure your joint. Narrow (under about 3 mm) points you to unsanded or epoxy.
Look at where it is going. Wet or greasy areas favour epoxy; dry walls are fine with cement.
Check the finish. Gloss glazes prefer smooth grouts to avoid scratching.
Pick your colour intent: match to quieten, contrast to define, tonal for the middle ground.

Order a sample first so you can hold the tile against grout colour cards in your own light before you commit. Samples are available through Tile Touch, we ship Australia-wide, and you can see the ranges in person at our Waterloo showroom in Sydney.

Frequently asked questions

Can I use sanded grout on kit kat finger mosaics?

Usually not the best choice. Kit kat mosaics are typically set with narrow joints that suit an unsanded grout, and sanded grout can scratch a gloss glaze during clean-up. If your joints are wider than about 3 mm, check the grout maker's joint range before deciding.

Is epoxy grout necessary in a shower?

It is not strictly required, but it is a good fit for showers because it resists water and stains and does not need sealing. Cement grout can work in a shower if it is properly sealed and maintained, though epoxy gives you less ongoing upkeep.

What grout colour works best with white mosaics?

A pale, close-matched grout keeps a white mosaic looking soft and unified. If you want the shape of each piece to stand out, a grey or darker grout will outline every joint. Try a sample against both before you choose.

Do glossy mosaics need special grout?

Gloss glazes are best paired with smooth grouts, either unsanded cement or epoxy, to avoid fine scratches from gritty sanded grout. Wipe away excess grout gently and promptly while it is still workable.

How do I stop grout colour looking patchy?

Mix each batch to the same consistency, avoid adding extra water, and try to grout a whole area in one go. Wiping too wet can wash pigment out of cement grout and leave uneven patches.