Terrazzo Flooring

This is a special kind of concrete flooring in that marble chips are used as aggregates and this concrete on polishing along with carborundum stone presents a smooth surface. It is extremely decorative and has good wearing properties. Since of this, it is widely used in residential buildings, offices, hospitals, schools and other public buildings. Terrazzo is a specially prepared concrete surface holding cement (white or grey) and marble chips (of different colors), in proportion to 1 : 2 to 1 : 3, while the surface has set, the chips are exposed through grinding operation. Marble chips might vary from 2 mm to 8 mm size. Color could be mixed to white cement to set desired tint. The flooring is, thus, more expensive.

The sub-base preparation and concrete base laying is completed in a same manner, as explained for cement concrete flooring. The top layer might have about 40 mm thickness, consisting of

(a)        34 mm thick cement concrete layer (1 : 2 : 4) laid over the base concrete, and

(b)       About 6 mm thick terrazzo topping.

Before laying the flooring; the whole area is divided within appropriate panels of predetermined size and shape. For this, aluminum or glass strips are used. The strips have the similar height as the thickness of the flooring (i.e. 40 mm). The strips are jointed to the base concrete, along with the help of cement mortar, and their tops are perfectly set to level and line. Alternate panels are filled. The width of the strips might be 1.5 to 2.0 mm.

The surface of base concrete is cleaned of dirt etc. and by wetted. The wet surface of the base concrete is smeared along with cement slurry. Concrete of grade 1: 2: 4 is then laid in alternate panels leveled and finished to rough surface. While the surface is hardened, the terrazzo mix (holding cement, marble chips and water) is laid and finished to the level surface. In further marble chips might be added during tamping and rolling operation, so in which atleast 85 percent of the finished surface show exposed marble chips. The surface is then floated and trowelled, and left to dry for 12 to 20 hours. After that, the surface is cured properly for two to three days.

The first grinding is completed, preferably through machine, using coarse grade (No. 60) carborundum stones, by using plenty of water. The ground surface is then scrabbed and cleaned. Cement grout of cream such as consistency, of the similar color, is then applied on the surface so in which pores and holes etc. are filled. The surface is cured for 7 days and then second grinding is done along with carborundum stones of fine grade (No. 120). The surface is scrabbed and cleaned thoroughly, and cement grout is again applied. The surface is cured for 4 to 6 days and final grinding is completed along with carborundum stones of 320 grit size. The surface is thoroughly scrabbed and cleaned, by using plenty of water. The floor is then washed along with dilute oxalic acid solution. At last, the floor is polished, with polishing machines the wheels of that are fitted along with felt or hessian bobs, to get fine shine. Wax polish is also applied within the help of the polishing machine, to get final glossy surface.