Article - Spacing, how much and why
It's worth looking at this area again as it is, alongside size, one of the most important areas to start with. If you make a neat mosaic you can 'read' it and it becomes, in effect, your textbook which you can refer back to.
Why have spaces?
If you have your tesserae in a straight line, if you want you can push them all up against each other so there are no gaps. This works fine with straight lines but once the pattern starts curving, to keep the same effect, no gaps, you then have to do a lot of cutting. This slows you down.
Don't try to make the exact same space around each tesserae. If you try to have 2mm gap around everyone then you will slow yourself up just as much as if you were trying to have no gaps. Some touch, some have spaces, take a look at the original mosaics have have a look for the gaps. I do go into this more in the online course but have a look at the image below and see how you generally have gaps but it's not exact.
Gaps too big?
If the gaps are too big then there is more chance of the grout being worn away over time exposing the edges of the tesserae. This makes it easier for peoples footwear to catch and to start dislodging them.