Code of practice for external facings and veneers, Part I: Stone facing

Scope of IS 4101 Part 1 (1967)

• Coverage:
  The standard covers simple, feasible fixing methods for structural components, specifically those practical for adoption in India.

• International Coordination:
  The code aligns with international standards and practices, adapting them to local field conditions.

• Rounding Off Values:
  All test or analysis results must be rounded as per IS 2:1960 rules, maintaining the same number of significant digits as specified values.

Key Points Summary:

No specific formulas or tables are given under the "Scope" clause; the focus is on applicability and standardization principles.

Reference:

• IS 2:1960 — Rules for rounding off numerical values
• IS 4101 Part 1 — Structural fixing methods and design principles

IS 4101 Part 1 - Key Definitions & Specifications Summary

1. Definitions (Clause 0.2.2 & 0.3)

• Methods of fixing covered are simple and feasible for current Indian practice.
• Standard aligns with international coordination and local field practices.
• Numerical results must be rounded per IS 2:1960 rules, retaining significant figures as specified.

2. Structural Design (Clause 5.2.2)

• When facings are supported by cramps, weight-induced stresses must be considered in cramps' design.
• Safe Working Stresses for Metal Cramps (Table 1):

Notes:

• Safe working stresses are constant working stresses, not directly proportional to 1% proof stress.
• Peak wind loads may cause stresses up to 1.5 times the constant working stress.

Summary Diagram of Metal Cramp Design Considerations

flowchart TD
    A[Facings Supported by Cramps] --> B[Calculate Weight-Induced Stress]
    B --> C[Select Metal Type]
    C --> D[Refer Table 1 for Safe Working Stress]
    D --> E[Design Cramp for Tensile and Shear Stresses]
    E --> F[Check for Peak Load (1.5x Stress Allowed)]
    F --> G[Finalize Cramp Design]

This concise info aids in understanding the **definitions, rounding

IS 4101 Part 1 - Materials: Key Formulas, Tables & Specifications

1. Safe Working Stresses for Metal Cramps (Clause 5.2.2, Table 1)

• Note: These stresses are permissible working stresses, not directly proportional to 1% proof stress.
• Peak stresses up to 1.5 × working stress allowed for wind loading.

2. Material Requirements

• Cramps (Clause 4.3): High corrosion resistance against dampness and chemical action of mortar/concrete.
• Metal Angle Supports (Clause 4.4):
  • Clean of mill-scale and rust.
  • Protective coating: galvanizing or phosphating + paint (per IS 1477 Part I & II).
  • Non-corrosive brass angles preferred.

3. Design Considerations

• Include stresses from facing weight on cramps.
• Use recommended working stresses for design safety.

flowchart TD
    A[Facing Weight] --> B[Stresses on Cramps]
    B --> C[Design of Cramps & Attachments]
    C --> D[Use Safe Working Stresses from Table 1]
    D --> E[Material Selection & Corrosion Protection]

Summary: Use Table 1 stresses for cramps, ensure corrosion resistance, and apply protective coatings on metal supports as per IS 4101 Part 1.

Fixing and Attachment Methods (IS 4101 Part 1)

1. Safe Working Stresses for Metal Cramps (Table 1, Clause 5.2.2)

• Note: Peak wind loads may increase stresses by up to 50% over these working stresses.

2. Attachment Arrangements (Clause 5.3.2.3)

• Single cramps:

  • If cramps cannot support weight: Use 3 cramps (2 top, 1 bottom) [Fig.1C].
  • If cramps can support weight: Use 3 cramps (2 bottom, 1 top) [Fig.1D].

• Double cramps:

  • Load-bearing: 4 cramps [Fig.1E].
  • Non-load bearing with grouted vertical joints: 2 cramps (1 top, 1 bottom) [Fig.1F].

3. Side Attachment (Clause 5.3.2.2)

• For horizontal joints, use:
  • One cramp on both sides [Fig.1A], or
  • Two cramps on one side, one on the other [Fig.1B].

4. Integral Bonding (Clause 5.3.3.1)

• Facing units with mechanical projections.
• Masonry bond/keying to backing.
• Combination of both.

flowchart LR
    A[Facing Unit] --> B[Single Cram

IS 4101 Part 1: Key Structural Design Requirements & Safe Working Stresses

1. Structural Design Considerations (Clause 5.2.1 & 5.2.2)

• Facings and attachments must resist positive and negative wind pressures (use IS 875-1964 for wind loads).
• For facings supported by metal cramps or attachments, include stresses from the facing weight in design.
• Design cramps and attachments based on permissible working stresses (see Table 1).

2. Safe Working Stresses for Metal Cramps (Table 1)

Notes:

• These stresses are constant working stresses; peak wind loads can be allowed up to 50% above these values.
• Values do not directly correlate to 1% proof stress due to material property differences.

Summary Diagram of Design Process

flowchart TD
    A[Start: Facings & Attachments] --> B[Calculate Wind Loads (IS 875)]
    B --> C[Calculate Weight-induced Stresses]
    C --> D[Select Metal Cramp Material]
    D --> E[Check Stresses ≤ Safe Working Stress (Table 1)]
    E --> F{Within Limits?}
    F -- Yes --> G[Design Approved]
    F -- No --> H[Redesign or Select Different Material]

**Use IS 875 for wind pressures and Table 1 for safe working stresses in cramps to ensure safe, durable masonry facing

Programming Work with Backing Wall Construction (IS 4101 Part 1)

Key Points & Specifications:

• Planning Inputs (Clause 3.1):

  • Dimensional details of walls to be faced/veneered.
  • Types & condition of backing walls.
  • Special design precautions for local climate.

• Waterproofing (Clause 5.6.2):

  • Use string courses or features to deflect water.
  • Seal vertical & horizontal joints near features with waterproof bitumen (Grade 250-500, per IS:1834-1961).

• Fixing Details (Clause 7.4.1):

  • Embed fixing cramps at proper positions during backing wall construction for facing attachment.

• Ashlar Masonry Facing (Clause 7.4):

  • Follow IS 1597 (Part II) for ashlar facing integrally built with backing wall.

Typical Fixing Arrangement (Conceptual):

graph LR
A[Backing Wall] --> B[Embedded Fixing Cramps]
B --> C[Stone Facing Units]
C --> D[Waterproof Sealed Joints]
D --> E[String Course for Water Deflection]

Notes:

• All dimensions in cm.
• Refer IS 1597 (Part II) for detailed ashlar masonry backing wall construction.
• Use copper pin dowels or embedded cramps as per fig. 5 in IS 4101 for fixing.

This ensures durable, weather-resistant stone facing integrated with backing walls.

IS 4101 Part 1: Jointing and Pointing Key Points

Joint Thickness & Mortar Mix

• Aggregate: Use crushed stone sand from the same stone as facing units for pointing mortar.
• Joint preparation: For filler/compound use, rake out joints 20-50 mm deep after initial mortar set.
• Joint sealing compounds: Choose based on shrinkage, hardening, cracking resistance, and oil retention; follow manufacturer's guidelines.

Design Considerations

• Larger facing units require joints to accommodate greater dimensional changes.
• Use specially designed sealing compounds or proven masonry mortars (1:1:6) for such cases.
• Water penetration mostly occurs through joints, not facing units.

flowchart LR
    A[Exposed Joints] -->|≤6 mm| B[Mortar 1:2:9]
    C[Close Butt Joints] -->|≤1.5 mm| B
    D[General Joints] -->|6-12 mm| E[Mortar 1:1:5 to 6]
    E --> F[Rake joints 20-50 mm for filler]
    G[Large Facing Units] --> H[Use special sealing compounds or 1:1:6 mortar]

This summary aligns with IS 4101 Part 1 clauses 7.3, 7.4.2, 4.6, and 5.6.

IS 4101 Part 1: Control of Alignment – Key Points

1. Joint Mortar (Clause 7.4.2)

• Mortar mix: 1:1:5 to 6 (Cement : Lime : Sand)
• Joint thickness: 6 to 12 mm
• Joint finishing: After initial mortar sets, rake out joints 2-5 cm deep for filler/compound application, then finish with suitable mortar.

2. Alignment Control (Clause 8.1.1)

• Uniform slab size: Ensures consistent alignment.
• Freedom from warping: Stone slabs must be flat and free from distortion.
• Fixing accuracy: Use cramps correctly to maintain alignment.

3. Metal-Angle Supports (Clause 4.4)

• Surface preparation: Remove mill-scale and rust.
• Protective coating: Galvanizing or phosphating + paint as per IS 1477 (Parts I & II).
• Material preference: Non-corrosive brass angles preferred over steel.

Summary Table: Joint and Alignment Control

flowchart TD
    A[Stone Slabs] --> B[Check Uniform Size]
    A --> C[Check Warping]
    B & C --> D[Fix with Cramps]
    D --> E[Control Alignment Achieved]

Note: Proper jointing and fixing techniques per IS 4101 ensure structural stability and aesthetic alignment in stone masonry facings.

Durability and Corrosion Protection as per IS 4101 (Part 1) - 1967:

Key Specifications:

• Metal Angle Supports (Clause 4.4):

  • Must be free of mill-scale and loose rust.
  • Protective coating required:
    • Preferably galvanizing.
    • Alternatively, phosphating + 1-2 coats of paint as per IS:1477 (Parts I & II).
  • Non-corrosive brass angles are preferred.

• Cramps Material (Clause 4.3):

  • Must resist corrosion in damp conditions and chemical action of mortar/concrete.

Safe Working Stresses for Metal Cramps (Clause 5.2.2, Table 1):

Notes:

• Working stresses are constant working stresses, allowing for 50% peak wind load increase.
• Protective coatings and corrosion-resistant materials are essential for durability.

Summary Diagram:

flowchart TD
    A[Metal Angle Supports] --> B[Clean surface: no rust/mill-scale]
    B --> C[Protective Coating]
    C --> D[Galvanizing (preferred)]
    C --> E[Phosphating + Paint (IS:1477)]
    A --> F[Non-corrosive Brass Angles (preferred)]

    G[Cramps Material] --> H[High corrosion resistance]
    G --> I[Safe Working Stress Table]

    I --> J[Tensile and Shear stresses

IS 4101 Part 1: Waterproofing and Moisture Control - Key Points

1. Waterproofing Measures (Clause 5.6.2)

• String courses or similar projections deflect water from building faces, reducing moisture penetration.
• Joints around these features must be sealed with waterproof compounds.
• Recommended sealing material: Bitumen Grade 250 to 500 (see IS:1834-1961).

2. Joint Sealing Compounds (Clauses 4.6, 5.5)

• Selection depends on:
  • Shrinkage resistance
  • Hardening rate
  • Crack resistance
  • Oil retention
• Use specialized joint sealing compounds suitable for the facing type and local weather.
• Essential for facings exposed to heavy rain and wind.

3. Design Considerations (Clause 5.2.1)

• Facings and attachments must withstand positive and negative air pressure from wind loads.
• Refer to IS 875-1964 for wind load design data.

Summary Table: Waterproofing Materials

Diagram: Water Deflection by String Course

flowchart TB
    A[Rainfall] --> B[String Course Projection]
    B --> C[Water deflected away]
    B --> D[Joints sealed with bitumen]
    D --> E[Prevents moisture penetration]

Note: Always verify compound compatibility with facing materials and local climatic conditions.

IS 4101 Part 1: Quality Control & Workmanship - Key Points

1. Structural Design & Workmanship (Clauses 5.2.1 & 5.2.2)

• Facings and attachments must resist positive and negative wind pressures (see IS 875 for wind load data).
• Attachments like cramps must be designed considering stresses from the weight of facings.

2. Safe Working Stresses for Metal Cramps (Table 1)

• Note: Safe working stresses are constant working stresses; peak loads can be 50% higher.

3. Rounding Off Results (Clause 0.4)

• Follow IS 2-1960 for rounding numerical test results.
• Retain significant figures consistent with specified values.

Summary Diagram: Facings & Attachment Stress Flow

flowchart LR
    A[Wind Load] --> B[Facings]
    B --> C[Weight of Facings]
    C --> D[Cramps & Attachments]
    B --> D
    D --> E[Structural Support]

References:

• IS 4101 Part 1 (1967)
• IS 875 (Wind Loads)
• IS 2 (Rounding Off Rules)

IS 4101 Part 1: References to Other Standards & Key Specifications

• Rounding Off Values:
  Follow IS 2-1960 for rounding numerical results in tests or calculations, keeping significant figures consistent with specified values.

• Wind Load Design:
  For wind pressure on facings and attachments, refer to IS 875-1964 for wind load data and design guidelines.

• Safe Working Stresses for Metal Cramps (Table 1):

• Notes:
  • Safe working stresses are constant working stresses; peak stresses (e.g., wind) can be allowed up to 50% higher.
  • These stresses do not directly correlate with 1% proof stresses due to differing metal properties.

Summary Diagram of Design References

graph TD
  A[IS 4101 Part 1] --> B[IS 2-1960: Rounding Rules]
  A --> C[IS 875-1964: Wind Loads]
  A --> D[Safe Working Stresses for Metal Cramps]
  D --> D1[Copper, Brass, Stainless Steel, Steel, Cast Iron]

This ensures structural safety by integrating international coordination, local practices, and relevant IS codes.