How to Grout Mosaics

How to grout mosaics by artist Kay Whitmarsh

I am often asked for extra tips on how to grout mosaics, particularly by my students.

It is slightly different to grouting normal tiles, because when you do a mosaic you create an abundance of grout lines. Most of my pieces are a little 3 dimensional and use unusual materials. This poses additional challenges.

First and foremost I tell everyone, is to take into account the grout areas of your piece. They will change the look of your artwork dramatically at the end. Quite often around half of the piece will end up being grout!

Mclaren Vale mosaic Project

Forming layers and creating height and interest.


Firstly choose your grout colour and look carefully at your piece to see if you think this will highlight your design. Secondly, identify any areas which may be more difficult to grout, raised pieces, changes in heights, things like glass beads. Make sure that there is no excess glue protruding above the level of the tiles, etc. If you do notice some areas of glue sticking up, they can be removed with a metal object (screwdriver, metal tweezers etc) during the grouting process. Dig the glue out and then add a little more grout while it is still wet. Of course clean of any surface glue as well with a damp rag as this will make the whole grouting process easier.

Next prepare your work space. Lay down some newspaper, find a block of some type about 10-15mm thick and use this as a stand to lift your piece above the newspaper. Have your tools ready – mixing tub for grout, grout float/squeegee, some water, dampened rag or sponge and dry rags. Also a good idea to have safety glasses and disposable gloves.

Mosaic Project

Getting ready to grout, area masked off for multiple colours and surface nice and clean


Add small amounts of water to the grout at a time, and mix until it is around the consistency of toothpaste. Then let it rest for a couple of minutes, it will thicken slightly.

Use your grout float/mixer to spread some grout onto the mosaic. Then with the grout float or squeegee work the grout back and forth across the surface, forcing it into all of the gaps. Form a nice angle edge around the outside of the mosaic. Remove as much excess grout as you can with the grout float.

Begin rubbing down the surface with the damp rag, or sponge, and remember to work slowly. Use your gloved fingers for any tricky bits but be careful as tile edges are sharp. Once your tiles begin to show through the grout layer you can buff off any excess with a dryer rag. As the grout begins to set you can rub harder to remove any excess from the tile surfaces. You can carefully smooth off the edges with the cloth as well. This will leave a nicely angled edge to help prevent water/moisture getting under your tiles.

Mclaren Vale mosaic Project

Grouting progress, panel is coming together

Trouble shooting

  1. Grout left on tile surface once completed – Grout may have been too thick or more buffing was needed with the dry rag.
  2. Grout has sunken low in the gaps between the tiles – Grout may have been too thin, or rag/sponge was too wet and pulled the grout back out of the gaps. (add another layer of grout)
  3. Details of the design have been covered by the grout – Take a photo of the piece before grouting and then reference this to see where extra buffing is required to reveal the tiles/features.
Mclaren Vale mosaic Project

Multiple grout colours

Design tips

Most of my designs use different materials and are often a little 3D. One of the ways to accentuate these design elements if to use more than one grout colour.

To do this simply identify the areas you would like in that particular colour. Mask off the surrounding mosaic (all areas not the colour your are using with masking tape or paper). Grout in the normal way, but once you have finished your initial buffing process, remove the masking tape. This allows you to clean up any areas, or remove any grout that has landed in the wrong place. To do the second colour, mask off the grouted area. Then grout the rest of the piece as before.

All photos used in this relate to my participation and work with various community groups during the Mclaren Vale Mosaic Project


If you would like to learn more I would love to see you at one of my classes

I hope this has helped you to learn how to grout mosaics. For more information regarding workshops and my exhibitions sign up for my quarterly newsletter.


A self employed artist living in idyllic Sellicks Beach in South Australia. Working in fused glass, mosaic, fabrics and printmaking. A variety of art is being sold around Adelaide, online and through exhibitions and workshops. There is a strong link between all art that is created and the natural environment. Having beautiful items in your home will enhance your quality of life and health. Buying local keeps local people employed, supporting artists creates stronger communities.

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