Interior Wall Latex Paint Application Process

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I. Prerequisites

1. Walls must be essentially dry with a base moisture content not exceeding 10%.

2. All plastering work shall be completed. Areas such as wall-penetrating pipes, openings, and internal/external corners shall be pre-leveled and repaired with plaster, and thoroughly dried.

3. Door and window glass installation shall be completed, wet-process floor construction shall be finished, and pipeline pressure testing shall be concluded.

4. Winter construction requires heating conditions, with an ambient temperature no lower than 5°C.

II. Application Process

1. Wall Cleaning: Remove all loose and peeling material from the wall. Patch with cement mortar, remove residual debris, and sweep the wall clean.

2. Wall Repair: Level dents, cracks, and uneven areas with gypsum plaster. After drying, sand down protruding parts and remove dust.

3. Applying Putty: The number of putty coats depends on wall evenness, typically three coats. For kitchens, toilets, and bathrooms, use water-resistant putty (polyvinyl acetate emulsion : cement : water = 1:5:1).

   • First coat: Apply horizontally with a rubber trowel, ensuring continuous strokes without overlaps. Finish neatly. After drying, sand smooth and clean.

   • Second coat: Apply vertically with the same material and method. Sand smooth and clean after drying.

   • Third coat: Touch up or apply fully with a rubber or steel trowel to achieve a smooth surface. After drying, polish finely with fine sandpaper, avoiding missed spots or over-sanding.

4. First Coat of Latex Paint: Paint the ceiling first, then the walls from top to bottom. Clean the wall and wipe dust with a cloth. Apply paint with a brush, removing loose bristles from new brushes. Stir paint thoroughly and dilute with water if needed to ensure even application. After drying, touch up putty, sand smooth, and clean.

5. Second Coat of Latex Paint: Same as the first coat. Stir thoroughly before use; avoid adding water if consistency is adequate to prevent transparency. After drying, sand off small bumps and brush marks, then clean.

6. Third Coat of Latex Paint: Same as the second coat. Due to rapid drying, work quickly and continuously. Start from one end and brush toward the other, blending strokes to avoid visible seams.

III. Quality Standards

1. Guarantee Items: Material type and color must meet design and sample requirements. Peeling, missed spots, or transparency are strictly prohibited.

2. Basic Items: Standards for intermediate-level painting.

   • Transparency, sagging, wrinkling: None on major surfaces; none in conspicuous areas on minor surfaces.

   • Gloss and smoothness: Uniform and consistent.

   • Decorative lines: Color separation lines straight, deviation ≤1mm (checked with a 5m line or full-length line for shorter distances).

   • Color and brush marks: Consistent color without obvious brush strokes.

VI. Finished Product Protection

1. Do not sweep floors until paint is dry to avoid dust contamination. Avoid splashing water near walls after drying to prevent soiling.

2. Protect painted walls from impact or damage after completion.

3. Avoid contaminating finished surfaces like floors, doors, windows, and glass during painting.

VII. Common Quality Issues and Solutions

1. Transparency: Caused by thin paint film. Ensure full coverage and maintain paint consistency; avoid excessive water dilution.

2. Visible Seams: Brush vertically with strokes closely blended. Delays between strokes cause visible seams. Ensure sufficient manpower for large areas.

3. Obvious Brush Marks: Maintain moderate paint consistency. Load brush appropriately and smooth strokes to minimize marks.

4. Uneven Color Lines: Mark lines carefully before painting. Use a straight edge for color separation lines, apply even pressure, and brush lightly from left to right with controlled paint load.
   For colored paint: Mix batches properly. Use the same batch for each coat on a single surface, and ideally use up in one go to ensure color consistency.