3" Sand Cushion – Historically the most crack-resistant system. A dusting of sand is spread on slab to act as ball bearings; tar paper or polyethylene is put down as a slip sheet: a reinforced underbed is installed to within ½" of the finish floor elevation; 1 ¼" divider strips are anchored into the setting bed with the top edge at the finished floor elevation to form panels no larger than 6’-0" per side and the ½" Terrazzo Finish (Portland Cement and marble Chips) is poured the next day to a level slightly above the finished floor elevation set by the strips.

The floor is allowed to cure four or five days and is then ground with a Terrazzo grinding machine using carborundum or diamond impregnated stones. A #24 grit is used first to cut down to the level of the divider strips, then a #80 grit is used to remove deep scratches; the floor is then grouted to fill air and/or water voids (same as voids along the sides of a core sample from concrete slab). The cement grout leaves a skim coat on the surface and the Terrazzo is often left in this condition while other messy work is completed. The skim coat protects against casual scratching.

The final polishing is done using either #110 or #220 stones, the Terrazzo is then washed and sealed with three coats of water based acrylic floor finish and sealer.

Every divider strip in this system acts as a control joint to take care of anticipated shrinkage and/or movement at control joints in the slab. This means that spaces develop between the Terrazzo Finish and the Divider Strips rather than a random crack.

2" Bonded Terrazzo- Similar to the typical mud-set ceramic or quarry tile. An underbed is installed 1 ½" thick over the slab with the 1 ¼" divider strips installed to within ½" of the finish floor elevation as in the Sand Cushion System and panels are no larger than 8’-0" per side. The rest of the installation and finishing is the same as the Sand Cushion.

The divider strips acts like the score mark in a concrete sidewalk to control shrinkage and casual movement in the vicinity of the divide strip. However, concrete movement in the center of a panel will result in a crack.

½" Monolithic Terrazzo – The least expensive Terrazzo system. The slab is acid washed (no dustproofer-sealer-hardener compounds should be used) and control joints in concrete slab are acknowledged with back "L" strips ½" high. Additional divider strips are only decorative and/or to provide method of change Terrazzo color. We always use an epoxy-bonding agent to promote adhesion between the ½" Terrazzo Finish (same as Portland Cement and Marble Chips in the mud-set systems). The floor is then cured and finished as above.

The best floor for the dollar. Although the Terrazzo will crack if the slab cracks, cracks are not a disaster or a failure. Cracks can be easily grouted to match the matrix and typically develop in the first year of building occupancy.

Does not usually require a slab depression and weighs about 6 lbs. per square foot.

3/8" Polyacrylate Modified Cement Terrazzo – Similar to ½" Monolithic Terrazzo in price, installation and lack of crack-resistance. The water is replaced with an acrylic (polyacrylate) emulsion and the same emulsion is used as a latex-bonding agent.

System is vulnerable to bastardization. Thirty-two percent solids emulsion (the recommended strength) looks exactly the same as sixteen percent solids emulsions (one that has been cut fifty percent with water).

¼" Epoxy Terrazzo – a true resinous Terrazzo. The Epoxy Resin has about three times the chemical and stain resistance of the cementitious matrices above. Installed and finished as ½" Monolithic with Epoxy Bonding Agent as recommended by the manufacturer.

The one-fourth inch system has about twice the tensile strength (crack resistance) of the cementitious types above. However the limited thickness severely limits the type of divider strip to the #16 gauge (1/16") white metal or brass and the maximum size of the marble chips is reduced from the usual #2 (3/8") to the smaller #1 (1/4") with resultant change in texture.

The concrete slab must have an effective vapor barrier placed directly below the slab for all on or below grade installations.

The Epoxy Terrazzo is available in any color of the rainbow just like epoxy paint. Exotic aggregates such as glass or mother of pearl can be used to create unique visual effects. In addition, the Epoxy Terrazzo takes a great polish and the hard surface is easier to maintain.