To grout or not to grout! I can across an interesting discussion the other day which shared a number of view points on whether you should grout or not. 

Reasons for grouting:

• It helps bring the piece together and unite it. 
• For outside pieces it helps protect the mosaic and adhesive
• It fills the gaps where you are using materials that are difficult to fit together tightly.
• If you have sharp edges, leaving the pieces un-grouted can result in injury if people touch the mosaic.

Reasons not to grout:

• Grouting changes the look of a mosaic which is not always for the better
• Grouting can darken a piece, particularly when it is going to be placed in low light areas
• Choosing the right colour for grout can be a headache and if you get it wrong can destroy the mosaic.
• Some people just don't like the process of grouting

Planning for grout from the start helps you incorporate it better in your design. Take the bowl below as a great example of this. The grout lines are not only integrated seamlessly into design but become a feature and focal point. The grout lines in this example are created by aligning the pieces to enable the grout to form a continuous line, and a separator of sections. 

Miss Molly's Designs, "The Blues" stained glass mosaic platter.

Think outside the box you can use grout lines to the branches of trees, to create letters or to colour areas where using tiles isn't feasible or is too fiddly. 

Grouting shouldn't just be an after thought. If you think about the whole design before you begin, the interplay of colours, textures, lines and shapes than the perceived risks associated with grouting should be diminished.

The questions of whether to grout or not comes down to what materials you are using, the purpose of the mosaic, the environment in which it will be housed and how you incorporate grout into your design. If you think about it as more than a filler than a world of possibilities opens up.