Portland Cement Terrazzo Flooring

Terrazzo flooring can be installed either as tiles, or poured in-situ on site. In-situ products can use an epoxy, polyacrylate, or Portland cement binder. This Common Product describes sand cushion terrazzo flooring, a Portland cement based in-situ product for interior use. Other types of Portland cement terrazzo flooring that were beyond the scope of this Common Product include bonded, monolithic, and rustic flooring. 

To install sand cushion Terrazzo flooring a layer of sand dusting is applied to an existing concrete slab. An isolation sheet is laid on top of this, followed by a galvanized wire mesh reinforcement. An underbed of Portland cement and sand is then poured. The combination of the isolation sheet, wire mesh, and cement underbed help offset minor imperfections in the substrate. These layers are then topped by a half-inch layer of gray or white Portland cement containing aggregates, such as marble or glass chips. Standard terrazzo flooring uses aggregate sizes #1 and #2 (⅛ inch and ¼ inch retained on a screen respectively). Venetian terrazzo, which uses larger aggregates, was beyond the scope of this Common Product. A wide variety of alkali-resistant pigments can also be added to the top layer. Zinc or brass dividers are placed in the underbed to offset expansion and contraction, and also allow for separation of sections that incorporate different pigments. 

After the terrazzo has been placed it is cured by covering it with either water or polyethylene sheeting. The flooring is then ground, grouted, polished, cleaned, and sealed. Accessories like grout and sealer can add additional hazards not considered by this Common Product.