Black grouts bring out the intensity of tile colors while white grouts overwhelm them. Natalie Knox’s Day of the Dead Skull mosaic is a good example of how well black grouts work and how a light colored backer isn’t a good indicator of the mosaic would look with white grout.
Don’t Be Fooled
If you lay the mosaic out on a white backer and try to use that as an indication of what the mosaic will look like with white grout, remember this:
When the gaps are filled with grout, they won’t have all the contrast provided by empty gaps, which have depth and shadow. A lot of white concrete at the same level as the surface of the glass tends to make the colors look washed out. Continue reading
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. Continue reading
Artist Risa Puno recently completed her interactive mosaic sculpture Common Ground for Rufus King Park in Jamaica Queens, NYC, and the project is a great example for discussing materials and methods for mosaic table tops.
No Plywood Backers Outdoors
Plywood is never an acceptable backer for outdoor mosaic table tops.
Humidity in outdoor air can cause plywood to swell, contract, and warp, and even if the displacement is too small to be noticed, it can still cause grout to crack and tiles to pop off. Once grout has hairline cracks, moisture can penetrate underneath, and then there isn’t any hope for the mosaic lasting after that happens.
If you have a wooden table that you want to mosaic for outdoors, then attach a piece of 1/4-inch concrete backer board over the top of the wood and mosaic on that.
Seal your finished outdoor mosaic with a tile and grout sealer and reseal it each fall. Silicone-based gout sealers are wipe-on-wipe-off and easy to apply. Most of the work is buffing off the excess so that the surfaces are slippery. Continue reading