Code of practice for in-situ waterproofing and damp-proofing treatments with glass fibre tissue-reinforced bitumen

IS 9918: Scope Summary

IS 9918 covers the general design, detailing, and preparatory work for damp-proofing and waterproofing of buildings.

Key Points:

• Scope: Applies to waterproofing and damp-proofing treatments in buildings to prevent moisture ingress.
• Materials Covered:
  • Bitumen primers
  • Glass fibre base coal tar pitch and bitumen felts
  • Industrial bitumen
  • Paving bitumen
• Recommended Materials: Pea-sized gravel/grit for concrete and masonry roofs (flat or sloping).
• Rounding Off: Numerical values for tests or calculations must be rounded as per IS 2:1960 (Rules for rounding off numerical values).

Important References:

This standard ensures uniformity in waterproofing practices and material specifications for building durability.

flowchart LR
    A[IS 9918 Scope] --> B[Waterproofing & Damp-proofing]
    B --> C[Materials]
    C --> D[Bitumen Primer (IS 702)]
    C --> E[Glass Fibre Felts (IS 1322)]
    C --> F[Industrial Bitumen (IS 702)]
    C --> G[Paving Bitumen (IS 73)]
    B --> H[Design & Detailing]
    B --> I[Use of Pea-sized Gravel]

IS 9918 - Definitions & Key Specifications Summary

Definitions (Clause 2.0)

• The standard covers general design, detailing, and preparatory work for damp-proofing and waterproofing in buildings.
• Terms like pea-sized gravel/grit are specified for use in concrete and masonry roofs (Clause 5.1).

Rounding Off (Clause 0.3)

• Numerical values must be rounded per IS 2:1960.
• Retain the same number of significant digits as the specified value.

Important Specifications Referenced

Notes

• Pea-sized gravel/grit is recommended for flat or sloping concrete/masonry roofs to aid waterproofing.
• The standard relies on related IS codes for material specifications.

Rounding Off Example (IS 2:1960)

If a specified value is 3.456 and the test result is 3.4567, round to 3.46 (two decimal places).

flowchart LR
    A[Test/Calculated Value] --> B{Number of Significant Figures?}
    B -->|Match Specified Value| C[Round off accordingly]
    C --> D[Final Value for Compliance]

This ensures consistency and clarity in reporting test results.

IS 9918: Surface Preparation Key Points

1. Surface Preparation (Clause 9.1)

• Follow IS 3067-1966 and IS 1609-1976 for surface prep standards.
• Keep site dry and free of water to ensure good adhesion.
• Walls must remain dry for proper bitumen adhesion and glass fibre impregnation.

2. Treatment for Concrete, Masonry & Metallic Roofs (Clause 6.2)

• Normal Duty Treatment:
  • Clean surface.
  • Apply bitumen primer at 0.4 kg/m².
  • Let primer become touch dry before next step.

3. Bonding Material (Clause 4.3)

• Use blown bitumen (IS 702-1961) or residual bitumen (IS 73-1961).
• Bitumen penetration ≤ 40 (IS 1203-1958 test).
• Heat bitumen to correct working temperature.

Summary Table for Surface Preparation

flowchart TD
    A[Start: Surface Cleaning] --> B[Apply Bitumen Primer (0.4 kg/m²)]
    B --> C{Primer Touch Dry?}
    C -- No --> B
    C -- Yes --> D[Apply Damp-Proofing Membrane]
    D --> E[Finish]

This ensures good adhesion and durability of damp-proofing layers per IS 9918.

IS 9918 - Materials Key Points

1. Bonding Material (Clause 4.3)

• Use blown bitumen (IS:702-1961) or residual bitumen (IS:73-1961) or a mix.
• Must withstand local temperature & slope conditions.
• Bitumen penetration ≤ 40 (IS:1203-1958 test).

2. Pea-Sized Gravel/Grit (Clause 5.1)

• Recommended for concrete and masonry roofs (flat or sloping).
• Provides surface protection and durability.

3. Bitumen Specifications

• Primer, glass fibre base felts, industrial & paving bitumen conforming to respective IS codes.
• Penetration test as per IS:1203 (first revision).

4. Rounding Off (Clause None: 0.3)

• Final test values rounded per IS:2-1960.
• Maintain same significant digits as specified values.

Typical Bitumen Penetration Test (IS:1203)

flowchart LR
    A[Bitumen Type] --> B[Blown Bitumen (IS:702)]
    A --> C[Residual Bitumen (IS:73)]
    B & C --> D[Penetration ≤ 40 (IS:1203)]
    D --> E[Used as Bonding Material]
    F[Pea-Sized Gravel] --> G[Concrete/Masonry Roofs]

This summary ensures compliance with IS 9918 material specifications for waterproofing.

IS 9918 – Surface Finish Key Points

Surface Finish (Clause 6.2)

For concrete, masonry, and metallic roofs (flat or sloping), IS 9918 recommends:

• Normal Duty Treatment:
  • Clean the surface thoroughly.
  • Apply bitumen primer at the rate of 0.4 kg/m².
  • Allow primer to become touch dry before further treatment.

Bonding Material (Clause 4.3)

• Use blown bitumen (IS:702) or residual bitumen (IS:73) or their mixture.
• Bitumen penetration should be ≤ 40 (tested as per IS:1203).
• Bitumen must be heated to the correct working temperature before application.

Rounding Off (Clause 0.3)

• Final test or analysis values must be rounded off per IS:2-1960.
• Retain the same number of significant digits as in the standard's specified value.

Summary Table: Surface Finish Treatment

flowchart TD
    A[Clean Surface] --> B[Apply Bitumen Primer (0.4 kg/m²)]
    B --> C[Allow Primer to Dry (Touch Dry)]
    C --> D[Apply Bonding Material (Bitumen ≤ 40 Penetration)]
    D --> E[Proceed with Waterproofing Layers]

This ensures proper bonding and waterproofing as per IS 9918 guidelines.

IS 9918 - In-Situ Waterproofing Treatment for Roofs: Key Specifications & Formulas

1. Treatment Types & Course Details

2. Typical Five-Course Treatment Sequence (Fig. 1)

1. Bituminous primer on dry surface
2. First coat of hot bitumen (1.6 kg/m² min)
3. First layer of glass fibre tissue (100 mm overlap)
4. Second coat of hot bitumen (1.6 kg/m² min)
5. Finishing with pea gravel/grit (0.006 m³/m²) or tiles/concrete

3. Notes on Finishing & Materials

• Pea gravel or grit: 0.006 m³/m²
• If gravel unavailable, coarse sand may be used
• Finishing options: tiles, patent stone, cement concrete
• For AC/GI corrugated roofs, refer to Fig. 5 for joint treatment with bituminous washers and leak-stop compound.

4. Additional Guidelines

• Overlap glass fibre layers by 100 mm in both directions
• For heavy and extra heavy duty, embed subsequent glass fibre layers perpendicular to previous
• Bitumen application rate: 1.6 kg/m² minimum per coat
• Adjust number of courses based on rainfall severity (moderate to very severe)

flowchart TD
    A[Dry Roof Surface] --> B[Bituminous Primer]
    B --> C[Hot Bitumen Coat 1 (1.6 kg/m²)]
    C --> D[Glass Fibre Tissue Layer 1 (100 mm overlap)]
    D --> E[Hot Bit

IS 9918: In-Situ Damp-Proofing Treatment for Basements & Below Ground Structures

Key Specifications & Steps (Clause 7.2):

Normal Duty Treatment (6-course)

1. Primer: Bitumen primer @ 0.4 kg/m², allow to dry.
2. Coats & Layers:
   • 1st coat hot bitumen @ 2.4 kg/m² (min).
   • 1st glass fibre tissue layer (100 mm overlap).
   • 2nd coat hot bitumen @ 2.4 kg/m² (min).
   • 2nd glass fibre tissue layer perpendicular to 1st.
   • 3rd coat hot bitumen @ 2.4 kg/m² (min).

Heavy Duty Treatment (8-course)

• Same as Normal Duty +
• 3rd glass fibre tissue layer (perpendicular).
• 4th coat hot bitumen @ 2.4 kg/m² (min).

Extra Heavy Duty Treatment (10-course)

• Same as Heavy Duty +
• 4th glass fibre tissue layer (perpendicular).
• 5th coat hot bitumen @ 2.4 kg/m² (min).

Notes:

• 6-course: Normal conditions
• 8-course: Severe conditions
• 10-course: Very severe conditions
• Optional 10-15 mm mastic asphalt layer (IS 1195:1978) for added protection on basement floors.
• Protect basement wall treatment during backfilling.

Summary Table:

flowchart TD
    A[Clean & Prime Surface] --> B[1st Coat Bitumen]
    B --> C[1st Glass Fibre Layer]
    C --> D[2nd Coat Bitumen]

IS 9918: Method of Laying In-Situ Waterproofing Treatment

Key Specifications & Steps (Clause 8):

• Surface Preparation:

  • Clean with wire brushes.
  • Prime entire surface with recommended primer.

• Application Process:

  1. Pour hot bitumen on surface (min 1.6 kg/m² for waterproofing).
  2. Embed glass fibre tissue with 100 mm overlap in both directions.
  3. Apply second coat of hot bitumen at 1.6 kg/m².
  4. For multi-layer, stagger joints midway.
  5. Embed finishing materials (pea gravel/grit at 0.006 m³/m²) into hot bitumen while wet.

Treatment Types & Coats:

Notes on Rainfall Severity for In-Situ Waterproofing:

• Moderate: <50 cm rainfall → 5 courses
• Severe: 50-150 cm rainfall → 7 courses
• Very Severe: >150 cm rainfall → 9 courses

Typical 5-Course Waterproofing Layer Sequence (Fig. 1):

graph TB
   A[Bituminous Primer on Dry Surface]
   B[1st Coat Hot Bitumen (1.6 kg/m²)]
   C[1st Glass Fibre Tissue Layer (100 mm overlap)]
   D

IS 9918: Method of Laying In-Situ Damp-Proofing Treatment

Key Specifications & Steps:

1. Surface Preparation

• Clean surface thoroughly (wire brush for waterproofing).
• Prime with bitumen primer @ 0.4 kg/m²; allow to become touch dry.

2. Bitumen & Glass Fibre Tissue Application (Above Ground & Basement)

• Each glass fibre layer is embedded perpendicular to the previous.
• Overlaps staggered and sealed with hot bitumen.

3. Additional Protection (Optional)

• Mastic asphalt coat: 10-15 mm thick (IS 1195-1978) for basement floors.
• Protective lining for basement walls during backfilling.

Summary of Coats for Normal Duty (Example):

Important Notes:

• Overlap joints: Minimum 100 mm, staggered in multi-layers.
• Number of courses:
  • Normal: 6 courses

IS 9918: List of Equipment and Tools for Laying In-Situ Glass Fibre Treatment (Clause 9.2 & Appendix A)

Key Equipment & Tools:

• Bitumen melting kettle with stirrer (for heating and maintaining hot bitumen)
• Rubber squeegees (for spreading bitumen evenly)
• Spraying or watering cans (for surface preparation or cleaning)
• Accessories: mineral turpentine, waste cotton, firewood, scaffolding (for support and safety)

Specifications for Laying Treatment (Summary):

• Overlap joints should be staggered midway between layers.
• Finishing materials embedded into hot bitumen while pouring.
• For basement damp-proofing, bitumen coat rate is higher (2.4 kg/m²) with more layers (up to 5 layers for extra heavy duty).
• Course of treatment varies by rainfall severity (5, 7, 9 courses for moderate to very severe rainfall).

Typical Five-Course Waterproofing Treatment (Fig. 1 Summary):

flowchart TB
    A[Bituminous Primer on Dry Surface]
    B[1st Coat Hot Bitumen]
    C[1st Layer Glass Fibre Tissue]
    D[2nd Coat Hot Bitumen]
    E[Pea Gravel or Grit Finish]

    A --> B --> C --> D --> E

Important Notes:

• Minimum 100 mm overlap on sides and ends.
• Joints between layers must be staggered.
• Care to avoid damage when laying heavy stone flooring.
• Protection (e.g., mastic asphalt) recommended for basement treatments.

This concise summary