Code of Practice for External Cladding, Part 3: Wall Tiling and Mosaics

IS 4101 Part 3 — Scope Summary

• Scope: Covers external facing work details for walls, including materials, design, and execution.
• Key Requirements:
  • Provide detailed info on:
    • Wall details, openings, and service fittings (Clause 3.1a)
    • Exposure conditions and usage situation (Clause 3.1b)
• Rounding Off: Final test or analysis values must be rounded per IS 2-1960 rules, maintaining the same significant figures as specified (Clause 0.6).
• Definitions: Clause 2.0 defines terms relevant to the standard.

Important Notes:

• The standard emphasizes accurate planning based on wall and environmental details.
• No direct formulas or tables in the scope clause; these appear in other parts of IS 4101.

IS 2-1960 Rounding Off Rule (Summary):

flowchart TD
    A[Start: Planning External Facing Work] --> B[Gather Wall Details]
    B --> C[Identify Openings & Fittings]
    C --> D[Assess Exposure & Usage Conditions]
    D --> E[Design & Material Selection]
    E --> F[Execution]

For detailed formulas and tables, refer to other clauses or parts of IS 4101.

IS 4101 Part 3 - Key Specifications for Materials

Mortar Materials (Clause 4.2)

• Mortar for floating coat and bedding must comply with:
  • 4.2.1 to 4.2.3 (details on cement, sand grading, and mix proportions).
• Mortar typically uses:
  • Cement: Ordinary Portland Cement (OPC)
  • Sand: Clean, graded fine sand
  • Water: Clean and potable

Bedding Materials (Clause 8.1)

• Bedding materials may be:
  • Cement-sand mortar (usual ratio 1:3 by volume)
  • Lime mortar or other specified mixes depending on application

Fixing Marble Mosaics (Clause 11.1)

• Use same fixing method as Clause 10 with an additional thin layer of:
  • 2 parts fine sand + 1 part cement on the back of mosaics after grouting

Rounding Off Test Values (Clause 0.6)

• Final test values must be rounded per IS:2-1960
• Retain the same number of significant figures as specified

Typical Mortar Mix Ratios (by volume)

Summary Diagram: Material Application Flow

flowchart TD
    A[Materials] --> B[Mortar for Floating Coat]
    A --> C[Bedding Materials]
    B --> D[Cement + Sand + Water]
    C --> E[Cement-Sand Mortar or Lime Mortar]
    E --> F[Fixing Marble Mosaics]
    F --> G[Apply Cement Grout + Sand-Cement Layer]

Note: For detailed mix proportions and grading, refer to Clauses 4.2.1-4.2.3 and 8.1 in IS 4101 Part 3 (1985).

IS 4101 Part 3 - Design Considerations: Key Points

1. Planning & Design Inputs (Clause 3.1)

• Wall details: Location of openings, service fittings.
• Exposure conditions: Weather, moisture, and environmental factors.
• These inputs ensure correct tile selection and fixing methods.

2. Battens for Tiling (Clause 4.4)

• Battens thickness = Tile thickness + Fixing bed thickness
• Materials: Timber, metal, plastic, or similar.
• Battens must be plane and true for even tile laying.

3. Early Tile Selection (Clause 5.1.2.2)

• Decide tile type early in design.
• Allows proper layout of walls, openings, and fixing details.

Summary Table: Battens Thickness

flowchart TD
    A[Design Stage] --> B[Select Tile Type Early]
    B --> C[Set Out Walls & Openings]
    C --> D[Determine Batten Thickness]
    D --> E[Tile Fixing Execution]

Ensure: Early tile choice → Accurate planning → Proper fixing → Durable external facing.

IS 4101 Part 3: Preparation of Backgrounds to Receive a Floating Coat

Key Specifications & Formulas:

• Purpose (Clause 7.1):
  Floating coat creates a suitable surface for tile fixing on unsuitable backgrounds.

• Surface Preparation (Clause 6.1):

  • Allow complete drying & shrinkage of background.
  • Clean surface thoroughly (remove dust, loose particles).
  • Remove existing coverings down to brickwork/concrete.

• Floating Coat Mix (Clause 7.2.2):
  For moderately weak/porous backgrounds (lightweight concrete, aerated concrete, low-strength bricks):

  • Cement : Sand = 1 : 4 to 5 (by volume)
  • Optional lime addition (to improve workability): up to 0.25 to 0.5 part lime by volume replacing sand.

• Strength Consideration (Clause 5.5.3):
  Floating coat strength ≤ Background strength to avoid differential shrinkage and surface shear.

• Additional Note (Clause 7.1):
  If floating coat has integral waterproofing and tiles fixed with sand-cement mortar, apply a suction coat of cement within 24 hours on the floating coat.

Summary Table: Floating Coat Mix for Weak Backgrounds

flowchart TD
    A[Background Surface] --> B{Is surface dry & clean?}
    B -- No --> C[Allow drying & clean surface]
    B -- Yes --> D{Background Strength?}
    D -- Weak --> E[Use Floating Coat 1:4 to 5 Cement:Sand + Lime]
    D -- Strong --> F[Use standard floating coat mix]
    E --> G{Waterproofing?

Application of Floating Coat for Tiles and Mosaics (IS 4101 Part 3)

Key Specifications & Formulas:

• Purpose: Create a suitable surface for tiles/mosaics when the background is unsuitable for direct fixing (Clause 7.1).

• Background Preparation:

  • Weak/disintegrating surfaces must be covered with metal lathing or wire netting (Clause 6.3.2).

• Floating Coat Mix:

  • For dense, strong, or moderately porous surfaces (e.g., high-density bricks, concrete, stone):
    • Cement : Sand = 1 : 3 to 1 : 4 (by volume)
    • Avoid stronger mixes (higher cement) to reduce drying shrinkage.
    • Avoid weaker mixes to maintain sufficient strength (Clause 7.2.1).

• Surface Finish:

  • Floating coat must be plumb and even with unevenness ≤ 1 in 600.
  • Surface should be scratched (not over-trowelled) to provide a key for bedding mortar (Clause 7.3.2).

• Waterproofing:

  • If floating coat contains integral waterproofing and tiles are fixed with sand-cement mortar, apply a suction coat of cement within 24 hours (Clause 7.1).

Summary Table:

flowchart TD
    A[Unsuitable Background] --> B{Is surface weak?}
    B -- Yes --> C[Fix metal lathing/wire netting]
    B -- No --> D[Apply floating coat (1:3 to 1:4 mix)]
    D --> E[Ensure surface plumb & unevenness ≤ 1/600]
    E --> F[Scratch surface for keying]
    F --> G{Is floating coat waterproofed?}
    G -- Yes --> H[Apply suction coat of cement within 24 hrs]
    G -- No --> I[Proceed with

Bedding Materials - IS 4101 Part 3 Key Points

1. Types of Bedding Materials (Clause 8.1):

• Bedding materials can be sand, cement mortar, or sand-cement mortar with additives.

2. Thick-Bed Definition (Clause 2.2):

• Thick-Bed: Bedding coat thickness > 3 mm.

3. Sand Quality (Clause 4.2.3.1):

• Sand for mortar bedding must conform to IS: 2116-1980 (Specifications for sand for masonry mortars).

4. Mortar Mix Ratio (Clause 8.1.2):

• Sand:Cement by volume = 3 to 4 : 1
• Additives (plasticizers, waterproofing agents) allowed per IS: 2250-1981.

Summary Table for Bedding Mortar Mix

Important References:

• IS: 2116-1980 — Sand for masonry mortars
• IS: 2250-1981 — Preparation and use of masonry mortars

flowchart LR
    A[Bedding Materials] --> B[Sand (IS:2116)]
    A --> C[Sand-Cement Mortar (3-4:1)]
    C --> D[Additives Allowed (IS:2250)]
    B --> E[Thin Bed (<3 mm)]
    C --> F[Thick Bed (>3 mm)]

This ensures proper bedding strength and durability per IS 4101 Part 3.

IS 4101 Part 3 - Clause 9.4: Grouting or Pointing of Tiles

Key Specifications:

• Timing: Grouting/pointing should ideally be done the day after tile fixing.
• Ideal Grout/Pointing Mix Properties:
  • Low shrinkage
  • Low compressive strength
  • Good adhesion
  • Impermeability
  • Easy cleaning

Mix & Application:

Notes:

• For pointing, adding fine sand improves workability.
• Work area size depends on climatic conditions (temperature, humidity) to avoid premature hardening.

flowchart LR
    A[Tile Fixing] --> B[Wait 1 day]
    B --> C{Joint Width}
    C -->|≤ 5 mm| D[Grouting]
    C -->|> 5 mm| E[Pointing]
    D --> F[Apply grout with squeegee]
    F --> G[Remove excess, polish dry]
    E --> H[Fill joints with pointing tool]
    H --> I[Clean surplus]

This ensures durable, neat tile joints with proper adhesion and minimal shrinkage.

Fixing of Marble Mosaics (IS 4101 Part 3)

Key Specifications:

• Tolerance: Finished surface should not deviate more than 1 in 200 from the general plane (Clause 9.5).
• Mosaic Size: Applicable for mosaics with area ≤ 900 cm²; larger sizes require special methods not covered here.

Fixing Method (Clause 11.1):

• Same as ceramic mosaics (Clause 10), with an additional step:
• After applying cement grout into joints, cover the back of marble mosaics with a thin layer of mortar made of:
  • 2 parts fine sand
  • 1 part cement
• This layer should be to the thickness level of the mosaic, compensating for thickness variation.

Final Grouting (Clause 10.5):

• Rub grout over joints to fill voids.
• Clean surface after grout hardens.
• Wash with 10% hydrochloric acid + 90% water solution, then clean water.

Summary Table:

flowchart TD
    A[Prepare base surface] --> B[Apply cement grout to mosaic joints]
    B --> C[Back of mosaic covered with 2:1 sand-cement layer]
    C --> D[Place mosaic and beat firmly]
    D --> E[Rub grout over joints]
    E --> F[Clean surface]
    F --> G[Wash with 10% HCl + 90% water]
    G --> H[Final clean water wash]

This ensures proper bonding, compensates for marble thickness variations, and provides a durable finish.