2. The cement base surface is flat, without bumps, honeycomb linen and cement knots. Request air smoothness is not greater than the thickness of painting request (with 3 meters ruler flat); appearance is dry, water content is less than 6, adhere to the air dryness and no oil pollution, bear in mind that after the air maintenance period of cement, 5 days before entering the construction site, can not wash or mop the ground with water. The PH value of the surface of the floor should be 6.0-8.0. There is no oil pollution, other paint, latex paint, bubble sugar and other residues in the air; the slope should meet the design requirements, and the allowable deviation value is 2% of the slope, and not more than 30 mm.