Outdoor mosaics must be made on concrete or stone or masonry, but that doesn’t mean you have to pour a concrete slab or do some other form of heavy construction.

Flagstones (flat paving stones) and concrete stepping stones are readily available at building material stores and lawn and garden centers. The flagstones are great if you want a natural irregular shapes, and the molded stepping stones are great for square and rectangular shapes.

Of course, thinset mortar must be used to attach the tiles, but that isn’t difficult to do, especially if you lay your mosaic up in advance on mosaic mounting tape or mounting paper.

If that seems complicated, it isn’t. I wrote some instructions for using packing tape and contact paper to lay up a mosaic design.

The last section of this article explains why you shouldn’t use plywood, Hardibacker, or (sometimes) even concrete backer board.