Code of practice for anti-termite measures in buildings, Part 1: Constructional measures

IS 6313 (Part 1) - 1981: Introduction & Scope - Key Points

Scope:

• Provides constructional measures for termite prevention in buildings.
• Focuses mainly on subterranean termites, the most destructive type.
• Measures include external preventive-cum-detection (e.g., termite shields, grooves, cement concrete aprons) and internal preventive methods (e.g., solid floors).
• Recommended to use all specified measures together for effective protection.
• Complements Parts II (chemical preconstruction treatment) and III (treatment of existing buildings).

Key Specifications:

• Use galvanized steel termite shields around the building perimeter except entrances.
• Provide anti-termite grooves at entrances.
• Construct cement concrete subfloors with 12 mm cement plaster.
• Provide lime concrete aprons around the building.

Typical Dimensions (mm):

Conceptual Diagram of Termite Shield & Groove

flowchart TB
    A[Building Periphery] --> B[Anti-Termite Shield (Galvanized Steel)]
    B --> C[Anti-Termite Groove at Entrance]
    C --> D[Cement Concrete Subfloor]
    D --> E[Lime Concrete Apron]

Summary:

• Termites cause severe damage; subterranean termites are primary concern.
• Mechanical barriers (shields, grooves, aprons) prevent termite entry.
• Use galvanized steel sheets as termite shields.
• Constructional measures must be combined for best results.
• Refer to IS 6313 (Part I) for detailed drawings and dimensions.

IS 6313 (Part 1) - Terminology & Key Specifications on Termite Protection

Key Terminology (Clause 2.1 & Appendix A)

• Termite Presence: Identified by visual signs or infestation evidence at construction site.
• Termite Shield: Physical barrier around building plinth to prevent termite entry.
• Termite Cap: Protective cover on pipes or timber sections at plinth level.
• Termite Collar: Ring fitted on down-water pipes to prevent termite ingress.

Important Specifications & Dimensions

• Termite Shield:
  • Installed all around the building plinth except at entrances.
  • Projection beyond outer edge of columns: 50 mm.
  • Turnover width: 50 mm.
• Anti-termite Groove:
  • Provided at entrances and junctions with termite shields.
• Termite Cap on Pipes:
  • Tight fit with pipe.
  • Sealed with coal tar pitch.
  • Bottom of down-water pipe should be at least 200 mm away from wall.

Material & Construction Notes

• Use galvanized steel sheets (plain or corrugated) for termite shields.
• Seal joints around bolts and caps with coal tar pitch (Clause 5.4.1).
• Cement concrete subfloor with 12 mm thick cement plaster under termite shield.

Visual Summary (from figures 11-15)

flowchart TB
    A[Building Plinth] --> B[Termite Shield]
    B --> C[Projection 50 mm]
    B --> D[Turnover 50 mm]
    A --> E[Anti-termite Groove at Entrance]
    F[Down-water Pipe] --> G[Termite Collar]
    G --> H[Termite Cap]
    H --> I[Sealed with Coal Tar Pitch]

This ensures a continuous physical barrier preventing termite ingress as per IS 6313 Part 1 (1981).

IS 6313 (Part 1) - Site Preparation & Preliminary Measures for Anti-Termite Construction

Key Specifications & Measures:

• Drainage (Clause 2.2):

  • Ensure no water stagnation near the building.
  • Construct a concrete apron around the building to prevent water access under the floor.

• Soil Preparation (Clause 4.1.1):

  • Remove roots, dead leaves, and organic matter from soil.
  • Place earth in layers ≤ 200 mm thick, compacted properly.
  • Insert dry bricks at least 50 mm deep into brick masonry for the apron floor.

• Dry Brick Dimensions (Fig. 1):

  • Standard dry bricks used for apron flooring (dimensions as per IS specifications).

Summary Table: Soil Layer & Brick Insertion

Notes:

• Proper site drainage and soil compaction reduce termite risk by eliminating moisture and organic food sources.
• Use coal tar pitch as per revised IS specifications for termite barriers.

flowchart TD
    A[Site Preparation] --> B[Remove organic matter]
    B --> C[Place soil in ≤ 200mm layers]
    C --> D[Compact soil layers]
    D --> E[Insert dry bricks ≥ 50mm]
    E --> F[Construct concrete apron]
    F --> G[Ensure drainage to prevent water stagnation]

This ensures effective termite control at the foundation stage as per IS 6313 (Part 1).

IS 6313 (Part 1) - 1981: Design Considerations for Termite Control

Key Constructional Measures (Clauses 3.2, 4.3, 5.4.1)

• External Protection:

  • Provide metal termite shields or masonry grooves around building periphery.
  • Use cement concrete aprons (minimum thickness ~75 mm) around the building to prevent termite access.
  • Metal shields must maintain proper shape; joints sealed with coal tar pitch if penetrated by bolts or pipes.

• Internal Protection:

  • Extend concrete sub-base fully under walls and plinth area without breaks.
  • For depressed floors (lift wells, bathrooms), ensure continuous sub-base.
  • Flooring laid over coarse sand layer (>3 mm grain size) to reduce soil moisture rise.

Typical Dimensions (from Figures 8, 9, 10)

Timber Selection (Clause 2.4)

• Use seasoned, naturally durable heartwood treated against subterranean termites.
• Refer IS 401:1967 (Timber preservation) and IS 1141:1973 (Timber seasoning).

Summary Diagram of Anti-termite Construction Layers (simplified):

graph TD
  Soil -->|Coarse sand layer (>3mm)| SandLayer
  SandLayer -->|Concrete subfloor (75 mm)| Subfloor
  Subfloor -->|Cement plaster (12 mm)| Plaster
  Plaster -->|Floor finish| Floor
  Subfloor -->|Anti-termite groove| Groove
  Groove -->|Metal shield / masonry groove| Shield
  Shield -->|Cement concrete apron| Apron
  Apron --> Soil

Note: Proper sealing of joints and continuous concrete layers are critical for effective termite barriers.

IS 6313 Part 1: Internal & External Anti-Termite Construction Methods

Key Specifications:

• External Protection:

  • Provide metal termite shields or masonry grooves around building periphery.
  • Use a cement concrete apron (lime concrete recommended) around the building.
  • Metal shields must maintain proper shape as termite barriers.
  • Masonry grooves act as physical barriers to termite entry.

• Internal Protection:

  • Extend concrete sub-base (≥75 mm thick) continuously under walls and plinth area.
  • For depressed floors (lift wells, bathrooms), sub-base must be continuous.
  • Lay concrete flooring over a coarse sand layer (>3 mm grain size) to prevent moisture rise.
  • Avoid vertical joints between floor and plinth masonry; fill joints with heavy grade coal tar pitch (IS 216-1961) if unavoidable.

Typical Dimensions & Layers (from Figures 8-10):

Construction Notes:

• Use stone masonry with lime mortar ≥1:3 when in contact with soil.
• Avoid voids in masonry or concrete to prevent termite ingress.
• Ensure continuous sub-base and flooring to block termite access.

flowchart TB
    Soil -->|Termite access| External_Protection
    External_Protection -->|Metal shields, grooves, apron| Building_Periphery
    Soil -->|Termite access under floor| Internal_Protection
    Internal_Protection -->|Concrete sub-base + sand layer| Floor
    Floor --> Building_Interior

This integrated approach ensures effective termite barriers both outside and inside the building, minimizing termite infestation risks.

IS 6313 Part 1 (1981) - Termite Shields, Caps, Frames, and Masonry Grooves

Function (Clause 5.1)

• To force termites to build visible entry tunnels for easy detection.
• Regular inspections are essential; frequency depends on local termite hazard.

Key Specifications & Details:

Construction Details (Figures 8, 9, 10)

• Stone masonry walls: Include anti-termite groove at plinth level.
• Brick superstructure: 75 mm concrete subfloor, anti-termite groove, 12 mm plaster.
• Junctions: Ensure seamless connection between termite shield and groove to block termite entry (see Fig. 13).

Installation Notes (Clause 5.2 & 5.2.4)

• Termite shields installed on walls under floors.
• At doorways/entrances where shields are impractical, use anti-termite masonry grooves.
• Proper sealing/junction treatment between shields and grooves is critical.

Summary Table of Anti-Termite Layers

IS 6313 (Part 1) - Installation & Maintenance of Termite Barriers: Key Points

1. Anti-Termite Constructional Details (Clause 4.3, Fig. 10)

• Stone Masonry Walls:
  • Anti-termite groove around plinth.
  • 75 mm thick cement concrete subfloor.
  • 12 mm thick cement plaster on walls.
  • Cement concrete topping and lime concrete apron around the base.
  • Floor finish over sand layer (> 3 mm grain size) to prevent moisture rise.

2. Termite Shields, Caps, and Frames (Clause 5.4.1)

• Holding down bolts passing through termite shields must be sealed with coal tar pitch.
• Termite caps on pipes must be tight fit and sealed similarly.
• Termite caps must cover the entire plinth section with 50 mm projection and 50 mm turnover beyond edges.
• Down-water pipes should have termite collars and caps soldered, with minimum 200 mm clearance from walls.

3. External & Internal Protection (Clause 3.2)

• External: Metal shields or masonry grooves + cement concrete apron.
• Internal: Continuous concrete sub-base under walls and floors, including pits.
• Sand layer (grain size > 3 mm) under concrete flooring to block moisture and termite access.

Summary Table: Typical Dimensions for Termite Barriers

Visual Concept (Mermaid Diagram)

flowchart TD
    A[Soil] --> B[Sand Layer (>3mm)]
    B --> C[Cement Concrete Subfloor (75mm)]
    C --> D[Anti-term

Short Note on Termites - Classification and Behavior (IS 6313 Part 1)

Classification:

• Subterranean Termites (Ground Nesting):
  • Build nests in soil
  • Require constant moisture
  • Construct covered tunnels for humidity, protection, and movement
  • Enter structures from ground level, attacking wood internally
• Non-Subterranean Termites (Wood Nesting):
  • Nest directly in wood without soil contact

Behavior:

• Subterranean termites maintain contact with soil and build mud tubes to access food sources.
• They destroy wood from inside, leaving a thin outer shell.
• Their tunnels ensure darkness and moisture, vital for survival.

Protection Measures (Clause 5.4.1):

• Seal joints between termite shields and bolts with coal tar pitch.
• Termite caps on pipes must fit tightly and be sealed with coal tar pitch to prevent termite entry.

flowchart LR
    Soil -->|Nest| Subterranean
    Wood -->|Nest| NonSubterranean
    Subterranean -->|Builds| Tunnels
    Tunnels -->|Access| Structure
    Structure -->|Damage| Wood

This classification and behavior guide termite control in structural design per IS 6313 Part 1.