One of the many wonderful characteristics of mosaics is their durability. Who knows how many generations can enjoy the art made from glass, china, ceramic, and stone tesserae? We do know that we can easily find mosaics that are 1,000 years older than the oldest paintings.
Choosing the right substrate for your mosaic is critical to its longevity. A mosaic that may get wet should be on a moisture resistant or waterproof backer. Cement board has been around the longest and may thereby be best known, but Skeewbackers are becoming widely recognized as a much better solution even better than Wedi board.
Yet there are still a lot of questions about how they compare. So we set out to find and report on the differences. But first, there are similarities. They are both:
Here are the differences:
Construction - Cement board is a combination of cement and reinforcing fibers formed into sheets of 3 feet by 5 feet or 4 feet by 8 feet.
Wedi is made with a dense polystyrene foam core sandwiched between thin layers of concrete which are reinforced with fiberglass mesh. The fiberglass mesh sticks out beyond the board and can be difficult to trim.
Skeewbackers are similar to wedi board with a high-density, waterproof extruded polystyrene core but they have a reinforced, waterproof membrane on both sides to give triple protection from water and vapor intrusion. No cement dust, no fiberglass mesh issues.
Weight - One square foot of ½ inch thick cement board weighs 40 ounces, wedi is 11 ounces, and Skeewbackers are the lightest at 5 ounces.
Water tightness – Cement board is water and mold resistant and Skeewbackers and Wedi is waterproof.
Shape - Cement board is not shapeable. Skeewbackers and Wedi can be shaped but wedi board has a cement and fiber coating that makes scoring tricky as it can crack and break. Skeewbackers cut and shape cleanly with no cracking or fibers.
Dimensions – Cement board is available in sheets with a thicknesses of 1/2 and 5/8 inch; widths of either 3 feet or 4 feet; and lengths of either 5 feet or 8 feet. Skeewbackers are available in ¼” and ½” and more thicknesses and lots of sizes and shapes as well as large panels. Wedi is available in sheets or panels with thicknesses 1/8, 1/4, 1/2, and more up to 4 inches; widths of 6 to 24 inches; and lengths of 6 to 24 inches.
Availability – Cement board is only available from building material suppliers and must be picked up at the store. Skeewbackers are available at Skeew.biz and are shipped worldwide. Wedi is also available online from mosaic supplies websites and may be available in local stores.
Cost – there is a large difference in their cost. Skeewbackers and Wedi board cost more than cement board, but the advantages outweigh cement board hands-down.
It is my opinion in working with all of the above backers, that foam-core backers provide the best option for mosaic backers and Skeewbackers are my favorite due to their lightness, ease of cutting, very clean edges.
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