Code of Practice for Whitewashing and Colour-washing

IS 6278: Scope Summary

• Purpose: Specifies methods for preparation of surfaces and application of whitewash and colour-wash on concrete, masonry, and plaster surfaces in buildings (Clause 1.1).

• Surface Preparation:

  • Old whitewashed/colour-washed surfaces must be broomed to remove dust, dirt, loose lime scales, and foreign matter (Clause 4.2.1).
  • Heavy scaling requires scraping the entire surface clean before re-application.

• Rounding Off Values:

  • Final test or analysis values should be rounded per IS 2-1960 rules, retaining the same significant figures as specified in the standard (Clause 0.4).

• International Coordination:

  • The standard aligns with international practices and local field conditions (Clause 0.3).

Key Specification References:

Rounding Off Rule (IS 2-1960)

• Round off numerical results to the same number of significant digits as the specified value.
• Example: If specified value = 12.3 (3 significant digits), round test results to 3 significant digits.

flowchart LR
    A[Surface to be whitewashed/colour-washed]
    B[Check if old whitewash/colour-wash exists]
    C[Remove dust, dirt, loose scales (brooming)]
    D[Heavy scaling?]
    E[Scrape entire surface clean]
    F[Apply whitewash/colour-wash]

    A --> B
    B -- Yes --> C
    C --> D
    D -- Yes --> E
    D -- No --> F
    E --> F
    B -- No --> F

This covers the scope and key preparatory steps per IS 6278.

IS 6278 primarily focuses on surface preparation and application of whitewash and colour-wash on concrete, masonry, and plaster, rather than detailed material properties.

Key Points on Materials from IS 6278:

• Surface Preparation:

  • Old whitewashed or colour-washed surfaces must be broomed to remove dust, dirt, loose lime scales, and foreign matter.
  • Heavy scaling requires scraping the entire surface clean before reapplication.

• Material Specifications Referenced:

  • Building limes (latest revision)
  • Common salt for chemical industries
  • Ultramarine blue and iron oxide pigments for paints (IS:44-1969)
  • Copper sulphate

• Rounding Off Values:

  • All test or calculated values must be rounded as per IS 2:1960, maintaining the same significant figures as specified.

Additional Notes (Engineering Practice):

• Whitewash Composition:

  • Lime (Ca(OH)₂), water, and additives like salt or pigments.
  • Common salt improves adhesion and durability.

• Colour-wash:

  • Lime mixed with pigments (e.g., ultramarine blue, ochre, iron oxide).

Summary Table: Common Materials & Uses

flowchart TD
    A[Old Surface] --> B{Is surface heavily scaled?}
    B -- Yes --> C[Scrape surface clean]
    B -- No --> D[Broom to remove dust/dirt]
    C --> E[Apply whitewash/colour-wash]
    D --> E

For detailed material properties, refer to respective IS codes cited above.

IS 6278: Scaffolding & Safety Measures for Whitewashing/Colour-washing

Key Specifications (Clause 3.1)

• Scaffolding erection: Should avoid resting on surfaces to be white/colour-washed.
• Suspended platforms (Jhoola): Must be properly secured and tied.
• Ladders: Use old gunny bags tied at top/bottom to prevent scratches on walls/floors.
• Ceiling work: Use proper stage scaffolding where necessary.

Surface Preparation (Clause 4.1)

• Surfaces (concrete, masonry, plaster) must be cleaned and prepared before application.

Colour Change (Clause 6.2.2)

• Apply 2 coats of whitewash before at least 2 coats of new colour-wash on prepared surfaces.

Safety & Practical Tips

• Ensure scaffolding is stable and tied to avoid displacement.
• Use protective padding on contact points.
• Maintain clear access and egress on scaffolds.
• Regularly inspect scaffolding for damage or wear.

Summary Table: Coats Application

flowchart TD
    A[Surface Preparation] --> B[Apply 2 coats Whitewash]
    B --> C{Colour Change?}
    C -- Yes --> D[Apply 2+ coats Colourwash]
    C -- No --> E[Finish]

For detailed scaffolding design loads and safety factors, refer to IS 3696 (Safety Code for Scaffolds and Ladders).

IS 6278: Preparation of Surfaces for Whitewash and Colour-wash

Key Specifications & Procedures:

• New Surfaces (Clause 4.1):

  • Clean thoroughly of dirt, dust, mortar drops, and foreign matter before application.

• Old Surfaces with Same Colour-Wash (Clause 4.2.1):

  • Broom to remove dust and dirt.
  • Remove loose lime wash scales and foreign matter.
  • Scrape heavily scaled surfaces clean before reapplication.

• Old Surfaces Spoiled by Smoke/Soot (Clause 4.2.3):

  • Scrape with steel wire brushes or steel scrapers.
  • Broom to remove dust.
  • Wash with clean water before whitewashing.

Important Notes:

• Surfaces must be dry and sound before application.
• Remove all loose particles to ensure good adhesion.
• Use steel wire brushes for tough soot/scaling.

Summary Table for Surface Preparation:

flowchart TD
    A[Surface Type] --> B{New Surface?}
    B -- Yes --> C[Clean dirt, dust, mortar]
    B -- No --> D{Old Surface with same colour-wash?}
    D -- Yes --> E[Broom, remove loose scales, scrape if heavy scaling]
    D -- No --> F{Old Surface spoiled by smoke/soot?}
    F -- Yes --> G[Scrape with steel wire brush, broom, wash with water]
    F -- No --> H[Assess and clean accordingly]

This ensures proper adhesion and durability of whitewash/colour-wash coatings as per IS 6278.

IS 6278: Preparation of Whitewash and Colour-Wash

Key Specifications & Formulas

1. Whitewash Preparation (Clause 1.3)

• Lime Cream Mix:
  • 1 kg unslaked lime + ~5 litres water → thin cream
  • Stand for 24 hours
  • Screen through coarse cloth
• Additives per m³ lime cream:
  • Gum: 1 kg (dissolved in hot water)
  • Sodium chloride: 1.3 kg per 10 kg lime (dissolved in hot water) → speeds carbonation, hardens coating
• Optional: Ultramarine blue up to 3 g/kg lime for last two coats (for slight tint)

2. Colour-Wash Preparation (Clause 5.2)

• Prepare sufficient quantity in one batch to maintain uniform shade
• Base: Whitewash solution as above
• Add mineral colours unaffected by lime (e.g., iron oxide red/yellow, chromium oxide green, carbon black)

3. Exterior Work Enhancement (Note 2)

• Mix 1 part tallow with 12 parts quick lime, slake with minimal water to thick paste, cool
• Thin and strain to wash
• If tallow unavailable, use linseed or castor oil (~10% dry lime weight)
• Oil forms insoluble soap → water-resistant coating
• Linseed oil may impart slight yellow tint

Summary Table

flowchart TD
    A[Unsalked Lime] --> B[Add ~5L Water]
    B --> C[Thin Lime Cream]
    C --> D[Stand 

IS 6278: Application of Whitewash and Colour-Wash — Key Points

Preparation of Colour-Wash (Clause 5.2)

• Prepare sufficient quantity of colour-wash in one batch to maintain uniform shade.
• Start with basic whitewash solution (per Clause 5.1).
• Add mineral colours stable in lime to the whitewash solution.

Application Procedure (Clause 6.2)

• Surface preparation as per Clause 4.1 (clean, smooth).
• For new works:
  • First coat: Whitewash.
  • Subsequent coats: Minimum two coats of colour-wash.
• Test a small area (~0.1 m²) with full coats to check shade uniformity before full application.
• Note: Small patches appear lighter than large surfaces.

Surface Preparation for Different Colour-Wash (Clause 4.2.2)

• Remove old colour-wash completely.
• Clean surface by brushing, scraping, or other means.
• Broom to remove dust and dirt.

Summary Table:

Notes:

• Uniform mixing is critical to avoid shade variation.
• Lime-resistant mineral pigments ensure durability.
• Hygienic and aesthetic finish requires adherence to these steps.

flowchart TD
    A[Surface Preparation] --> B[Apply 1st Coat Whitewash]
    B --> C[Test 0.1 m² for Shade]
    C --> D{Shade Uniform?}
    D -- Yes --> E[Apply 2+ Coats Colour-Wash]
    D -- No --> F[Adjust Mix and Re-test]
    E --> G[Final Uniform Finish]

IS 6278: Protective Measures for Whitewashing and Colour-washing

Key Specifications (Clause 6.2.2)

• Surface Preparation: As per Clause 4.2.2 (clean, dry, and sound surface).
• Whitewash Application: Apply two coats of whitewash before colour-wash.
• Colour-wash Application: Minimum two coats of the new shade.
• This ensures proper adhesion and uniform colour.

Additional Notes

• The standard aligns with international practices (Clause 0.3).
• Numerical results should be rounded off per IS 2-1960 rules (Clause 0.4).

Summary Table for Application

Conceptual Flow

flowchart TD
    A[Surface Preparation] --> B[Apply 2 Coats Whitewash]
    B --> C[Apply Minimum 2 Coats Colour-wash]
    C --> D[Finished Surface with Protective Colour Layer]

This process ensures durability, aesthetic finish, and protective qualities of the surface coating.