Glass Mosaic Tile Art: Base Materials

Making wonderful glass mosaic tile art is easy!  Let me show you how.

Tesserae can be adhered to almost any type of base material.  Size and weight of the finished work, and where and how the work will be displayed are the primary factors to consider when selecting your base material.  Glass is heavy, so the base material must be robust enough to support the weight of the tesserae and grout.  Indoor mosaics that remain dry (i.e., not displayed in steam rooms or similar environments) may be made using wood as the base.  Outdoor mosaics exposed to the weather should be made with backerboard or other water-proof material.

Regardless of the base type, the surface must be clean, free of oil and grease, and with no loose paint or other coverings such as wallpaper.  If not already roughed (especially wood), it’s best to sand or otherwise rough the surface to give the adhesive something extra to “grab” (e.g., scratch it with a flat tip screwdriver or score it with a razor blade knife).

Wood is my favorite base material for indoor hanging mosaics.  It can be easily cut to any size and shape and is relatively cheap.  For my indoor wall-hangings, I prefer 3/4-inch cabinet grade plywood pre-cut at my favorite home improvement store into 2’x4’ pieces (each piece costs about $15).  The standard pre-cut 2’x4’ size limits me to a maximum mosaic width of two feet.  I like this limitation because it prevents me from going crazy and creating gigantic mosaics that take forever to finish.  Over the years, I’ve found that 24”x30” is a good size for wall-hangings of any subject, so the 2’x4’ pre-cut size is just right for me.

I prefer cabinet grade because it’s already sanded and isn’t warped, and the cheaper grades usually have gouges, nicks, and knot holes.  The 3/4-inch plywood is plenty strong enough to handle the weight of the tesserae and grout, and it’s plenty thick enough to accept the 1/2-inch screws needed to install the frame clips and hanging wire.  The 3/4-inch thickness also resists warping, which is important for mosaics.  If the base warps, the grout will likely crack and tesserae will likely pop off.

Bare-wood furniture (i.e., unpainted and unstained), boxes, mirror frames, and other doodads at your favorite craft store make delightful indoor mosaics.

For outdoor mosaics, I prefer backerboard.  The two most common types of backerboard are water-resistant greenboard sheetrock and cementitious-type ceramic tile backerboard.

Greenboard is water-resistant but not waterproof.  Unlike standard drywall, greenboard has a moisture-resistant paper and a treated core.  Although treated, it disintegrates with prolonged exposure to water.  Therefore, don’t use greenboard for outdoor mosaics.

Cement backerboard is strong and water-resistant.  It won’t disintegrate with prolonged exposure to water, and it won’t warp due to changes in temperature or humidity.  Typical cement backerboard is formed with a solid cement core reinforced on both sides with fiberglass mesh.  Hardibacker is a brand of backerboard made with proprietary materials, which don’t include fiberglass mesh.  Hardibacker is purportedly stronger and lighter than other brands.  Cement backerboard or Hardibacker is the best base material for outdoor mosaic tabletops, walls, panels, mailbox address plates, and various other flat mosaic projects.

Terracotta is a hard, brownish-orange mixture of clay and sand used in pottery.  Flower pots are typical examples of terracotta and look wonderful as mosaics.

Cement-based stepping stones and birdbaths make beautiful outdoor mosaics.

Glass plates, bowls, and vases make lovely indoor mosaic knickknacks and keepsakes.

You can mosaic just about anything as long as it’s strong enough to hold the weight of the tesserae, it’s durable enough to endure the environment in which the mosaic will be displayed, and it’s properly prepared (sanded, sealed, etc.).

Remember, making mosaic art is easy. You can do it.  Yes, you can!