Painting the Walls of Cement Prefabricated Houses

The painting of walls in cement prefabricated houses can be carried out according to the following steps, with attention to relevant considerations:

I. Pre-construction Preparation

1. Wall Condition Inspection: Inspect the moisture content and alkalinity of the walls. If the moisture content is too high or the alkalinity is too strong, ventilation and drying or the use of an alkali-resistant primer is required. For new walls, remove residues (such as release agents, floating dust, etc.) and apply putty for leveling, ensuring that the wall flatness error does not exceed 3 millimeters. For old walls, sand the surface to enhance adhesion and prevent new paint from cracking due to the脱落 (peeling) of old paint layers.
2. Material Selection: Prioritize the use of branded wall consolidators, primers, and topcoats, ensuring that environmental indicators (such as VOC content) comply with national standards and that performance metrics such as weather resistance and adhesion are up to standard. For example, primers should have the functions of sealing alkalinity and preventing salt efflorescence, while topcoats should be selected based on the usage scenario, such as matte, semi-gloss, or high-gloss types.

II. Construction Steps

1. Wall Cleaning:
   • Remove protruding cement lumps, mortar residues, etc., to prevent bumps after painting.
   • Sweep the floor dust with a broom, then use an industrial vacuum cleaner for secondary cleaning of the walls and floor to ensure no fine particles are attached, preventing a grainy texture on the paint film.
2. Wall Treatment:
   • Apply a wall consolidator to solidify surface dust and enhance the bonding force between the putty layer and the wall. The wall consolidator should be applied evenly, avoiding missed areas or accumulation.
3. Primer Application:
   • Use a large roller to蘸取 (dip) an appropriate amount of latex paint and apply it continuously from the top of the wall downward, maintaining uniform pressure to avoid drips or brush marks.
   • Use a small roller to supplement areas that the large roller cannot cover, such as around sockets and switches, corners, and the edges of door and window frames, ensuring complete primer coverage.
   • After primer application, close doors and windows and allow it to dry naturally for about a week, depending on the ambient temperature (recommended 5-35°C) and humidity (≤85%), to prevent the primer from cracking due to rapid ventilation.
4. Topcoat Application:
   • Ensure that the primer is completely dry (no sticky feeling when touched); otherwise, it may cause the topcoat to bubble or peel.
   • After the first coat of topcoat, it can resolve issues such as wall mottling and color differences. Apply a second coat after an interval of 2-4 hours to enhance the paint film thickness and hiding power, ultimately achieving a uniform white wall effect.

III. Considerations

• Avoid painting during rainy days or when humidity is too high to prevent moisture from affecting the drying of the paint film.
• Keep painting tools clean and avoid mixing different colors or types of paints.
• Maintain ventilation after painting to accelerate the curing of the paint film, but avoid direct strong winds blowing on the walls.