Code of Practice for External Facings and Veneers, Part II: Cement Concrete Facing

IS 4101 Part 2: Scope & Key Specifications Summary

The scope of IS 4101 Part 2 (1967) covers external facing and veneering work on walls, focusing on planning, design, and execution. Key points include:

1. Scope & Definitions (Clauses 2.0 & 3.1)

• Applies to external facing/veneering on walls.
• Requires detailed information on:
  • Wall dimensions and backing type/conditions.
  • Method of attachment: independent support or rigid backing.
  • Openings and embedded services: locations of chases, pipes, etc.
  • Special design precautions based on local climate.

2. Design Considerations (Clause 5.1)

• Structural design must ensure durability and stability of facing.
• Must consider load transfer, wind pressure, thermal movements.

3. Material Specifications

• Water used must be clean and free from harmful substances (Clause 4.4.5).

Typical Design Parameters & Checks

Attachment Methods Illustration

graph LR
A[Wall Backing] --> B[Independent Support]
A --> C[Rigid Attachment]
B --> D[Anchors or Brackets]
C --> E[Direct Bonding or Ties]

For detailed formulas and tables, refer to IS 4101 Part 2 sections on structural design and attachment detailing. This standard emphasizes planning with full dimensional and environmental data for safe, durable external facing.

IS 4101 Part 2 - Definitions & Key Specifications for External Facing/Veneering

Key Definitions (Clause 2.0)

• Defines terms related to external facing and veneering.
• Ensures uniform understanding for design and execution.

Essential Planning Data (Clause 3.1)

For efficient design and execution, provide:

• Dimensional details: Wall thickness, height, type of backing.
• Attachment method: Independent support or rigid attachment.
• Openings & embedded items: Location/details of openings, chases, pipes, services.
• Special precautions: Design considerations for local climate and conditions.

Rules for Rounding Off Numerical Values

• Follow standard rounding rules as per IS 4101 Part II (1967) for all dimensions and calculations.

Typical Attachment Methods (Summary)

Structural Design (Clause 5.1)

• Design must consider load transfer, durability, and compatibility with backing.
• Ensure proper anchorage and allowance for differential movements.

flowchart LR
    A[Wall Backing] --> B[Attachment Method]
    B --> C{Type}
    C -->|Rigid| D[Fixed Facing]
    C -->|Independent| E[Separate Support]
    D & E --> F[External Facing]

Summary: IS 4101 Part 2 emphasizes detailed dimensional data, attachment methods, embedded services, and climatic considerations for external facing design. Use proper rounding and structural design per clauses for safe, durable facings.

IS 4101 Part 2: General Requirements and Coordination

Key Specifications & Requirements

• Detailed Information to be Furnished (Clause 3.1):

  • Dimensional details of walls, type & condition of backing.
  • Method of attachment: independent support or rigid fixing.
  • Location/details of openings, chases, pipes, service lines.
  • Special design precautions for local climate or conditions.

• Information & Drawings (Clause 3.2):

  • All necessary data and instructions must be provided to facing contractors for planning and execution.

• Metal Angle Supports (Clause 4.3):

  • Steel angles must be free from mill-scale and rust.
  • Protective coating: galvanizing or minimum two coats of paint as per IS 1477 (Parts I & II).
  • Non-corrosive brass angles are preferred.

Notes on Rounding Off Numerical Values

• Follow revised rules as per IS 4101 Part II - 1967 for consistency in dimensions and tolerances.

Summary Table: Metal Angle Support Coating

flowchart TD
    A[Planning Stage] --> B[Provide Dimensional Details]
    B --> C[Specify Attachment Method]
    C --> D[Mark Openings & Services]
    D --> E[Note Special Design Precautions]
    E --> F[Prepare Drawings & Instructions]
    F --> G[Execution by Contractors]

This ensures coordination and clarity for external facing/veneering work as per IS 4101 Part 2.

IS 4101 Part 2 (1967) — Materials Key Points

1. Mortar Materials (Clause 4.4)

• Mortar for external facing/veneering must use specified materials ensuring durability and bond.
• Cement, sand, and additives should conform to relevant IS standards.
• Proper grading and cleanliness of sand are essential for mortar strength.

2. Metal Angle Supports (Clause 4.3)

• Steel angles must be free from mill-scale and loose rust.
• Protective coating required:
  • Preferably galvanizing.
  • Or at least two coats of paint as per IS 1477 (Part I & II).
• Non-corrosive brass angles are preferred for longevity.

3. Planning & Design Info (Clause 3.1)

• Provide detailed dimensional data of walls and backing.
• Specify attachment method: independent or rigid.
• Include openings, chases, drainage, service lines.
• Account for local climate and special precautions.

Reference Standards:

Summary Table: Metal Angle Support Protection

flowchart LR
    A[Wall Backing] --> B[Attachment Method]
    B --> C{Independent or Rigid?}
    C -->|Independent| D[Supports Required]
    C -->|Rigid| E[Direct Fixing]
    D --> F[Metal Angle Supports]
    F --> G[Steel Angles]
    F --> H[Brass Angles]
    G --> I[Surface Prep & Coating]
    H --> J[Non-corrosive]

This concise summary aligns with IS 4101 Part 2 clauses on materials for external facing and veneering.

IS 4101 Part 2 - Design Considerations Summary

Key Design Considerations (Clauses 3.1 & 5.1)

• Dimensional details of walls, backing type & conditions.
• Attachment method: independent support or rigid fixing.
• Openings & embedded services: location/details of chases, pipes, etc.
• Local climatic effects: special precautions based on environment.
• Water quality (Clause 4.4.5): must be clean, free from harmful materials.

Structural Design (Clause 5.1.1)

• Facings and attachments must resist positive and negative wind pressures.
• Refer to IS 875 (Part 3) - Wind Loads for design wind pressure data.

Important Formula (Wind Pressure)

[ p = 0.6 \times V^2 ]

Where:

• ( p ) = design wind pressure (kN/m²)
• ( V ) = design wind speed (m/s)

(From IS 875 Part 3)

Design Workflow

flowchart TD
    A[Gather Wall & Backing Details] --> B[Select Attachment Method]
    B --> C[Check Openings & Embedded Services]
    C --> D[Apply Local Climatic Precautions]
    D --> E[Calculate Wind Loads (IS 875)]
    E --> F[Structural Design of Facings & Attachments]

Note: Always round off numerical values as per IS 4101 (Part 2) guidelines for consistency.

Fixing and Jointing of Facings as per IS 4101 Part 2 (1967):

1. Types of Joints (Clause 6.1)

• Butt joints
• Single joggled joints
• Double joggled joints
• Grouted joints (see Fig. 2, 3, 4)

2. Methods of Attachment (Clause 5.2.1)

• a) Cramps hold units; weight transferred to unit beneath.
• b) Cramps hold and support units; weight transferred to backing.
• c) Mechanical bonding via projections in facing units.
• d) Masonry bond or keying to backing.
• e) Combination of above methods.

3. Cramps (Clause 5.4.1)

• Number and position depend on facing size, weight, and workmanship.
• Minimum cramps shown in Fig.1 for various attachment types (side, top-bottom, center).
• Adjust cramps if longer side orientation changes.

4. Grouted Joints (Clause 6.6)

• Fill all horizontal and vertical joints with cement-sand grout.
• For horizontal joints: fill upper groove completely.
• For vertical joints: use rolled paper to plank/caulk outer joint, remove after partial set.
• Point joints immediately after grout sets.
• Cramps can be used additionally for support/load bearing.

Summary Table: Attachment & Jointing

Key Notes:

• Use cramps as per Fig.1 arrangements.
• Grouted joints improve stability and weather tightness.
• Combination methods often yield best performance.

flowchart LR
    A[Facing Unit] -->|Fixed by| B(Cramps)
    A -->|Bonded

IS 4101 Part 2 — Attachment Details Summary

Key Attachment Methods (Clause 5.2.1)

• Cramps hold facing units only; weight transferred to unit beneath.
• Cramps hold and support units, transferring weight to backing.
• Mechanical projections in facing bond into backing.
• Masonry bond or keying to backing.
• Combination of above methods.

Cramps Positioning & Number (Clause 5.4.1)

• Depends on facing type, unit size, weight, and workmanship.
• Minimum cramps shown in Fig. 1 (diagrammatic).
• Modify number based on site conditions.
• Cramps arranged for longer side vertical; adjust for horizontal.

Specific Attachment Types:

• Centre Attachment (5.4.5): One central cramp for horizontal joints of double joggle or grouted core (Precast only).
• Side Attachment (5.4.2):
  • One cramp on both sides (Fig. 1A), or
  • Two cramps on one side and one on the other (Fig. 1B).
• Top & Bottom Attachment: As per Fig. 1 (D).

Typical Arrangement (Fig. 1)

• Shows cramps for Side, Top & Bottom, Centre attachments.

Typical Cramps Arrangement (Simplified)

graph LR
A[Side Attachment] -->|1 cramp both sides| B(Facing Unit)
C[Side Attachment] -->|2 cramps one side + 1 other| B
D[Centre Attachment] -->|1 central cramp| B
E[Top & Bottom Attachment] -->|cramps at top and bottom| B

Notes:

• Use cramps suitable for double joggle or grouted core joints.
• Adjust cramps for facing orientation.
• Ensure cramps are compatible with precast or masonry facing.

For detailed dimensions and exact number refer to Fig. 1 of IS 4101 Part 2.

IS 4101 Part 2 - Surface Finishes Key Points

Types of Surface Finishes (Clause 4.1.2.1)

• Smooth trowel finish
• Wood float finish
• Cork float finish
• Scraped surface finish
• Rubber sponge float finish
• Sand surface face down finish (see IS 2402-1963)
• Pebble dash finish
• Rough cast finish
• Cast-stone finish

Reference Standard for Finishes

• Detailed specifications and procedures for external rendered finishes are provided in IS 2402-1963 (Code of Practice for External Rendered Finishes).

Metal Angle Supports (Clause 4.3)

• Steel angles must be free of mill-scale and loose rust.
• Protective coatings:
  • Preferably galvanized.
  • Or at least two coats of paint as per IS 1477 (Part I & II).
• Non-corrosive brass angles are preferred for durability.

Summary Table: Surface Finish Types and Characteristics

Additional Notes:

• For design and execution, provide detailed info on wall dimensions, backing type, attachment method, and embedded services (Clause 3.1).
• Consider local climate and conditions for finish selection and precautions.

flowchart LR
    A[Surface Finish Types] --> B[Smooth Trowel]
    A --> C[Wood Float]
    A --> D[C

Corrosion Protection for Metal Components (IS 4101 Part 2)

Key Specifications:

• Metal Angle Supports (Clause 4.3):

  • Must be free from mill-scale and loose rust after fabrication.
  • Protective coating required:
    • Preferably hot-dip galvanizing.
    • Alternatively, at least two coats of paint as per IS 1477 (Part I & II).
  • Non-corrosive brass angles are preferable for better durability.

• Cramps (Clause 4.2):

  • Material must resist corrosion in damp conditions and against mortar/concrete chemical action.
  • Typically use corrosion-resistant steel or brass.

• Finishing Standards:

  • Refer IS 2402-1963 for detailed finishing methods.
  • Painting and allied finishes per IS 1477 (Parts I & II).

Protective Coating Summary

Typical Corrosion Protection Workflow:

flowchart LR
    A[Fabrication] --> B[Remove mill-scale & rust]
    B --> C{Choose Protection}
    C -->|Galvanizing| D[Hot-dip galvanize]
    C -->|Painting| E[Apply 2 coats paint (IS 1477)]
    C -->|Brass| F[Use brass angles]
    D & E & F --> G[Installation]

Note: Always ensure compliance with referenced IS codes for coatings and materials to ensure durability and structural safety.

IS 4101 Part 2: Support Systems for Facings — Key Points

Methods of Attachment (Clause 5.2.1)

• a) Cramps hold facing units in position; weight transferred to the unit below.
• b) Cramps hold and support units; weight transferred to backing.
• c) Facing units have projections mechanically bonded into backing.
• d) Masonry bond or keying to backing.
• e) Combination of above methods.

Support Specifications (Clause 5.2.2)

• Continuous supports at ground and storey levels (projections/recesses in slabs, beams, metal angles).
• Vertical spacing of supports ≤ 3.5 m.
• Supports required over heads of openings and transitions in facing thickness.
• Intermediate supports essential to prevent progressive failure.

Design Considerations (Clause 5.1.2 & 5.3)

• Design cramps to resist stresses from facing weight.
• Projections must be reinforced; provide adequate cover to reinforcement in severe exposure to prevent corrosion.

Typical Support Spacing & Detailing Summary

Diagram: Support System for Facings

graph TD
    A[Concrete Backing] --> B[Facing Unit]
    B --> C{Support Method}
    C -->|Cramps only| D[Weight to unit below]
    C -->|Cramps + support| E[Weight to backing]
    C -->|Projections| F[Mechanical bond + reinforcement]
    C -->|Masonry bond| G[Keying into backing]
    C -->|Combination| H[Mixed methods]

    subgraph Supports at intervals ≤ 3.5 m
        I[Projection/Recess in slab]
        J[Beam between columns]
        K[Metal angle on slab/beam]
    end

    I --> B
    J --> B
    K --> B

This concise summary aligns with IS 4101 Part 2 clauses and provides practical design guidance for support systems of facings.

IS 4101 Part 2: Precast Concrete Facing Blocks - Key Points

• Reference Standard: Blocks must conform to IS 2185-1962 for general requirements.

• Special Treatments:

  • Durability, color, and surface texture must be enhanced for exposed faces.
  • Horizontal core machine: Use a special face mix with waterproofing compound cast integrally, matching moisture movement with the body.
  • Vertical core machine: Apply combing marks on one face, then treat with a waterproofing face mix.
  • Optionally, a richer waterproofed mix can be used throughout if cost permits.

• Durability Considerations:

  • Facing blocks must accommodate higher dimensional changes due to weather exposure.
  • Concrete mix design should focus on minimizing moisture movement and enhancing waterproofing.

• Fixing Techniques:

  • Selection depends on exposure conditions and type of facing units.
  • Jointing mortars and fixing devices must be compatible with the facing blocks.

Typical Mix and Waterproofing Notes:

Moisture Movement Consideration Formula (Conceptual)

[ \Delta L = \alpha \times L \times \Delta T + \beta \times L \times \Delta H ]

• (\Delta L): Dimensional change
• (\alpha): Thermal expansion coefficient
• (\beta): Moisture expansion coefficient
• (L): Length of block
• (\Delta T), (\Delta H): Changes in temperature and humidity

flowchart LR
    A[Precast Block Body Mix] --> B[Waterproofing Compound]
    C[Face Mix] --> B
    B --> D[Integral Casting or Surface Treatment]
    D --> E[Durable, Weather-Resistant Facing Block]

Summary: Use IS 2185 blocks with special waterproofed face mixes, ensure moisture compatibility between face and body, and apply suitable fixing methods per IS 4101 Part 2 for durable precast concrete facing blocks.

Moisture Control Measures per IS 4101 Part 2 (1967):

Key Specifications:

• Mortar Application (Clause 5.5.2):

  • Use dabs of mortar instead of full bedding to reduce moisture travel from backing to facing.
  • Trade-offs: less impact protection, risk of warping, and weaker cramp fixing.

• Water Deflection Features (Clause 5.5.3):

  • Incorporate string courses or similar to deflect water on high buildings.
  • Seal vertical/horizontal joints around these features with waterproofing compounds.
  • Recommended sealing material: Bitumen Grade 250 to 500 (see IS 1834-1961).

Additional Notes:

• Ensure clean water free from harmful impurities in mortar (Clause 4.4.5).
• Detailed planning of facings including backing type, attachment method, and openings is essential (Clause 3.1).

Summary Table for Moisture Control

flowchart TD
    A[Backing] -->|Moisture travels| B[Facing]
    B --> C{Mortar Application}
    C -->|Full bedding| D[High moisture transfer]
    C -->|Dabs of mortar| E[Reduced moisture transfer]
    F[String Course] --> G[Water deflection]
    G --> H[Sealed joints with bitumen]
    H --> B

This approach balances moisture control with structural integrity and durability.

IS 4101 Part 2 - Quality and Workmanship: Key Points

1. Planning & Design Information (Clause 3.1):

   • Provide dimensional details of walls, backing types, and conditions.
   • Specify attachment method: independent support or rigid fixing.
   • Detail openings, chases, pipes, service lines embedded.
   • Note special design precautions for local climate or conditions.

2. Materials:

   • Water used must be clean and free from deleterious substances (Clause 4.4.5).

3. Finishes:

   • Refer IS 2402-1963 for details on various finishes (Clause 4.1.2.2).

4. Rounding Off Numerical Values:

   • Follow IS 4101 Part II rules for rounding dimensions and quantities for accuracy.

Typical Specification Summary Table

Attachment Methods Diagram

graph LR
A[Wall Backing] --> B[Independent Support]
A --> C[Rigid Attachment]
B --> D[Facings fixed with brackets]
C --> E[Facings bonded directly]

Summary: Ensure detailed design info, clean materials, proper attachment, and finish standards per IS 4101 Part 2 and related IS codes for quality external facings and veneers.

IS 4101 Part 2 - References to Related Standards: Key Points

This part of IS 4101 (1967) focuses on external facing and veneering work, emphasizing the need for detailed coordination with related standards for effective design and execution.

Key Specifications:

• Dimensional details of walls and backing types must be clearly specified.
• Attachment methods: Whether facings are independently supported or rigidly fixed to backing.
• Embedded elements: Location/details of openings, chases, pipes, and service lines.
• Design precautions: Must consider local climate and special conditions.

Related Standards to Reference:

• IS 4101 (Part I): General requirements for facing and veneering.
• IS 456: Code of practice for plain and reinforced concrete (for backing design).
• IS 875: Code of practice for loads (wind, live, etc.).
• IS 1200: Methods of measurement for building works.
• IS 1905: Code of practice for structural use of masonry.

Rounding Off Numerical Values:

• Follow the revised rules as per IS 4101 Part II for consistency in calculations.

Summary Table for Attachment Methods:

flowchart LR
    A[Wall Dimensions & Backing] --> B[Attachment Method]
    B --> C{Type of Attachment}
    C -->|Independent| D[Separate Support Structure]
    C -->|Rigid| E[Fixed to Backing]
    A --> F[Embedded Services]
    A --> G[Design Precautions]
    G --> H[Climate Considerations]

Use this framework to coordinate with related IS codes ensuring safe, durable external facing and veneering work.

IS 4101 Part 2 (1967) - Annexures & Illustrative Figures Key Points

1. Planning & Design Data (Clause 3.1)

• Provide dimensional details of walls to be faced or veneered.
• Specify type and condition of backing (masonry, concrete, etc.).
• Define the method of attachment:
  • Independent support or rigid attachment to backing.
• Detail openings, chases, drainage pipes, service lines embedded.
• Note special precautions for local climatic or site conditions.

2. Rounding Off Numerical Values

• Follow standard rounding rules for all dimensional and design values to maintain uniformity.

3. Annexures and Illustrative Figures

• Typically include:
  • Dimensional sketches of wall facings.
  • Attachment details (e.g., anchors, ties).
  • Cross-sections showing backing and facing layers.
  • Service embedding locations.

4. General Specifications

• Use standardized dimensions and tolerances.
• Ensure compatibility of materials between backing and facing.

Summary Table: Attachment Methods

flowchart LR
    A[Wall Backing] --> B[Attachment Method]
    B --> C{Type of Attachment}
    C -->|Rigid| D[Rigidly Fixed Facing]
    C -->|Independent| E[Separately Supported Facing]
    D & E --> F[Final External Facing]

Note: For detailed formulas and tables, refer to specific annexures in the full IS 4101 Part 2 document or related IS codes on masonry and facing work.