Not liking the pre-fab stepping stone options out there, I decided to take matters into my own hands and make one with glass mosaic tile. It’s easy to do using what’s called the “indirect method” in which you press the tiles onto a piece of contact paper. You then use that sheet of tile to cast your new, custom stepping stone.

The first step is to come up with a design, either hand drawn or printed out from the computer. Since you’ll be working in reverse, you flip your design left-right. I chose the mercury, the symbol of transformation (it seemed like a good metaphor for a garden). No need to flip this particular image, of course. When sizing the design I like to keep in mind the size of the tiles I’ll be using so that any lines are about one tile wide.

I transferred the design to a piece of clear contact paper. Next, I taped the contact paper, with the sticky side up. to a piece of melamine coated fiberboard. Melamine is a good material to use because it helps it has a very smooth, even surface and is unlikely to warp. In addition, using melamine for the sides of the mold helps it release more easily. I built this mold out a piece of a discarded Ikea bookshelf.

While I was cutting the bottom piece, I cut four additional small pieces of the bookshelf to form the sides of the mold.The dimensions of these pieces determine the size of your stepping stone. I made a simple box by joining the pieces with screws at the corners. If you wish, you can spray the sides of the mold with WD-40 to help release the mold later. I forgot to do this, but it released fine anyway

For the mosaic itself, I used glass mosaic tile leftover from an old project. The glass picks up reflections and shimmers on a sunny day. The drawback is that it’s pretty expensive. The brand we’ve used in the past is Bisazza. You can also, of course, use broken plates, pebbles, pieces of metal or tile left over from other jobs.

To cut glass tile I use a pair of tile nippers. I like to break the square tiles into four small pieces to simulate the irregular look of ancient mosaics. I wear a pair of safety glasses and do the cutting in a box to keep shards of glass from flying around. I also do this outside or in the garage so little shards of glass don’t end up in our house. Once cut, I press the little tile pieces against the sticky side of the contact paper–face down, or “good side” down.  The sticky paper holds them in place.

When you’re finished sticking all the tiles down, it’s time to mix up some concrete. I used one part Portland cement to three parts builder’s sand. I poured my concrete into the mold and used some chicken wire as reinforcement. I just cut the wire into a rough square that would fit in the mold, poured half the concrete, placed the wire in the mold, then finished the pour. 

Once cast, I put the stepping stone in a garbage bag to slow down the curing process. After a couple of days I carefully removed the mold. One advantage of this technique is that it’s “self-grouting”: the concrete should flow between the tiles during the pour. It worked well, but I will have to do a small amount of grouting to fix a few spots the concrete did not reach.  

You could also use this same reverse method to make designs that could be pressed into a mortar bed when tiling, say, a kitchen or bathroom.

For more garden mosaic ideas see a previous post we did on the subject that includes a link to the stunning pebble mosaic work of Jeffery Bale.