Code of practice for flat-roof finish: mud phuska

IS 2115: Scope and Key Specifications for Roof Finishing

Scope Summary (Clause 3.1 & 3.2)

• Applies to roof finishes using mud phuska and similar materials.
• Requires detailed info before work:
  • Area of roof to be finished.
  • Roof levels and slope direction for drainage.
  • Details of parapet walls.
  • Information on waterproofing or supplementary treatments below mud phuska.

Important Notes

• All values and test results must be rounded off as per IS 2:1960.
• Drawings and preparatory instructions must be provided to the finishing team.

Key Specifications

Rounding Off (IS 2:1960)

• Round off final values to same significant figures as specified values.
• Ensures consistency in compliance checking.

flowchart TD
    A[Project Design] --> B[Provide Roof Area]
    A --> C[Specify Roof Levels & Slope]
    A --> D[Detail Parapet Walls]
    A --> E[Specify Waterproofing]
    B & C & D & E --> F[Preparation & Drawings]
    F --> G[Roof Finishing Execution]

This ensures efficient planning and quality control in roof finishing per IS 2115.

IS 2115: Definitions & Key Specifications Summary

• Clause 2.0 (Definitions):
  Defines terms specific to the standard for mud phuska roofing, ensuring clarity in interpretation.

• Clause 0.4 (Rounding off values):
  Final test or analysis values must be rounded per IS 2-1960 (Rules for rounding off numerical values).

  • Retain the same number of significant digits as the specified value.

• Clause 3.1 (Information for Roof Finish Planning):
  Essential data before roof finishing:

  • a) Roof area to be finished
  • b) Levels & slope direction for drainage, including parapet details
  • c) Waterproofing or supplementary treatments below mud phuska

• Clause 3.2 (Communication):
  All above details and preparatory drawings must be provided to the roofing team before starting work.

Important Note on Rounding (IS 2-1960)

This ensures uniformity and precision in reporting test or design values related to mud phuska roofing under IS 2115.

IS 2115: Planning and Construction Requirements for Roof Finish

Key Points from Clauses 3.1 to 6.4:

• Planning Information (Clause 3.1):

  • Area of roof to be finished.
  • Levels & slope direction for drainage, including parapet wall details.
  • Waterproofing and supplementary treatments below mud PHUSKA.

• Communication (Clause 3.2 & 3.3):

  • Provide all above info and preparatory drawings to roofing team before work starts.
  • Ensure coordination and information exchange among all executing parties.

• Protection Against Dampness (Clause 6.4):

  • Waterproof sub-floor if moisture percolation is suspected.
  • Waterproof roof surface up to 150 mm above sub-floor level on walls.

Typical Design Specification Summary:

Recommended Workflow Diagram:

flowchart TD
    A[Start Planning] --> B[Determine Roof Area]
    B --> C[Set Levels & Slope Direction]
    C --> D[Design Parapet Walls]
    D --> E[Select Waterproofing Treatment]
    E --> F[Prepare Drawings & Instructions]
    F --> G[Distribute Info to Roofing Team]
    G --> H[Coordinate Execution]
    H --> I[Apply Waterproofing & Mud PHUSKA]
    I --> J[Finish Roof]

References:

• IS 2115 (Roof Finish)
• IS 3370 (Waterproofing Concrete Structures)
• IS 269 (Ordinary Portland Cement)
• IS 2115 Annexures for mortar and tile specifications

This ensures a durable, well-drained roof finish with proper waterproofing and coordination.

IS 2115: Protection Against Water Penetration - Key Points

1. Protection Against Dampness (Clause 6.4)

• Moisture percolation from sub-floor or side walls must be prevented by waterproofing/damp-proofing.
• Waterproofing should extend at least 150 mm above the sub-floor level on walls adjoining the roof.
• Follow relevant IS codes on waterproofing and damp-proofing (e.g., IS 3370 for concrete structures).

2. Waterproofing Specifications

• Use materials conforming to:
  • Burnt clay flat terracing tiles (IS 1237 Part I & II)
  • Ordinary and low heat Portland cement (IS 269)
  • Portland slag cement (IS 455)
  • Portland pozzolana cement (IS 1489)
  • Sand for masonry mortars (IS 2116)
  • Burnt clay pozzolana (IS 2222)
  • Masonry mortars code (IS 2250)

3. Laying & Curing (Clause 10.1 & 11.1)

• Finished roof surface must be kept wet for at least 7 days for proper curing.
• Follow IS codes on waterproofing flat roofs.
• Proper treatment at roof-parapet junctions to prevent leakage.

Typical Waterproofing Layer Detail (Simplified)

graph TD
    A[Roof Slab] --> B[Waterproofing Layer]
    B --> C[Protective Screed]
    C --> D[Roof Finish / Tiles]
    D --> E[Parapet Wall with 150mm Waterproofing]

Summary Table: Minimum Waterproofing Height

Note: Always consult the latest IS codes for detailed waterproofing methods and materials.

IS 2115: Materials - Key Specifications & Guidelines

• Material References:

  • Burnt Clay Pozzolana: First revision specification.
  • Burnt Clay Flat Terracing Tiles: Part I (Machine made) & Part II (Hand made).
  • Cement Types:
    • Ordinary & Low Heat Portland Cement (Third revision).
    • Portland Slag Cement (Third revision).
    • Portland Pozzolana Cement (Second revision).
  • Sand for Masonry Mortars (First revision).
  • Code of Practice for Preparation & Use of Masonry Mortars.

• Rounding Off Test Results (Clause 0.4):

  • Follow IS 2-1960 for rounding.
  • Retain significant figures equal to those in the specified value.

• Protection Against Dampness (Clause 6.4):

  • Waterproof sub-floor if moisture percolation is suspected.
  • Waterproof roof surfaces up to 150 mm above sub-floor level where side wall moisture ingress is likely.

• Preparatory Work (Clause 3.2):

  • Provide all necessary drawings, instructions, and material info to those finishing the roof before work starts.

Common Material Properties (Typical values for burnt clay pozzolana tiles):

flowchart TD
    A[Material Specifications] --> B[Burnt Clay Pozzolana]
    A --> C[Terracing Tiles (Machine/Hand Made)]
    A --> D[Cement Types]
    D --> D1[Ordinary Portland Cement]
    D --> D2[Portland Slag Cement]
    D --> D3[Portland Pozzolana Cement]
    A --> E[Sand for Mortars]
    A --> F[Mortar Preparation Code]

For detailed mix ratios and testing methods, refer to respective IS codes cited above.

IS 2115: Sub-floor Preparation Key Points

1. Surface Leveling (Clause 6.2)

• Sub-floor must be reasonably even and at the required level.
• Ensures proper laying of roof finishes and prevents ponding.

2. Protection Against Dampness (Clause 6.4)

• Moisture prevention is critical.
• Waterproofing must follow relevant IS codes (e.g., IS 3370 for waterproofing concrete).
• Roof surface must be waterproofed up to at least 150 mm above sub-floor level to prevent side-wall moisture ingress.

3. Mortar for Grouting (Clause 5.11)

• Cement mortar mix:
  1 part cement : 3 parts sand (by volume).
• Use richer mixes if required.
• Addition of burnt clay pozzolana recommended with ordinary cement for enhanced durability.

4. References for Materials

• Use materials conforming to:
  • IS 269 / IS 1489 (Portland Cement)
  • IS 2116 (Burnt Clay Pozzolana)
  • IS 1542 (Sand for Masonry Mortars)
  • IS 2250 (Code of Practice for Masonry Mortars)

Summary Table: Mortar Mix for Sub-floor Grouting

flowchart TD
    A[Sub-floor Preparation] --> B[Leveling to required surface]
    A --> C[Waterproofing]
    C --> D[Waterproof up to 150 mm above sub-floor]
    A --> E[Mortar Grouting]
    E --> F[Cement : Sand = 1:3]
    E --> G[Add Burnt Clay Pozzolana if ordinary cement used]

Ensure compliance with referenced IS codes for materials and waterproofing details.

IS 2115: Mud Plaster - Key Specifications & Application

Soil & Mix Proportions (Clauses 5.2 & 5.3)

• Soil requirements:
  • Free from roots, gravel, coarse sand > 2 mm.
  • Coarse material ≤ 10% by mass.
  • Plasticity Index: 10% to 15%.
  • Free from harmful salts.
• Mud plaster mix:
  • Soil (dry, powdered) + water.
  • Wheat straw: 6% by mass (any size, breaks down during rotting).
  • Cow dung: 12% by mass.
  • Allow mixture to rot for ≥ 7 days, pugging manually to ensure homogeneity.

Application (Clauses 7.3 & 8.1)

• Apply plaster over mud PHUSKA.
• Total thickness: ≥ 25 mm.
• Preferably in two coats:
  • First coat: 15 mm.
  • Second coat: 10 mm.
• Allow drying for ≥ 24 hours.
• Fill any cracks with grout made of binder material (usually GOBRI).
• Check surface slope and evenness with straight edge & spirit level; rectify as needed.

Summary Table

flowchart TD
    A[Soil Preparation] --> B[Mix soil + water]
    B --> C[Add 6% wheat straw + 12% cow dung]
    C --> D[Rot for ≥7 days, pug manually]
    D --> E[Apply plaster on mud PHUSKA]
    E --> F[Apply 1 or 2 coats (15mm + 10mm)]
    F --> G[Dry for ≥24 hours]
    G --> H{Cracks?}
   

IS 2115 - Protective Coatings (Leeping Plaster) Key Points

Composition (Clause 5.6)

• Mix soil + equal volume cow dung + water to form a thin paste.
• Soil must be free from coarse sand and gravel.
• Optional: Add 5% cut back bitumen by dry soil mass for waterproofing.

Application (Clause 8.2)

• Apply a thin coat of Leeping plaster of minimum 3 mm thickness over dried mud plaster.
• Allow drying; fill hair cracks with grout made from binder (usually Gobri) as per Clause 7.3.
• Finish surface with trowel or float.

Crack Filling (Clause 7.3)

• Dry surface for at least 24 hours.
• Fill cracks with grout of binder material used in Leeping plaster.

Waterproofing Guidance (Clause 6.4)

• Treat sub-floor and walls against moisture per relevant IS waterproofing standards.
• Waterproof roof surface up to 150 mm above sub-floor level to prevent side wall moisture ingress.

Summary Table: Leeping Plaster Specifications

flowchart TD
    A[Soil + Cow Dung + Water] --> B[Mix to Thin Paste]
    B --> C{Add 5% Bitumen?}
    C -- Yes --> D[Add Bitumen]
    C -- No --> E[Proceed]
    D --> E
    E --> F[Apply 3 mm Leeping Plaster]
    F --> G[Dry Surface ≥ 24 hrs]
    G --> H{Cracks?}
    H -- Yes --> I[Fill Cracks with Binder Grout]
    H -- No --> J[Finish with Trowel/Float]

This ensures effective protective coating with waterproofing and crack resistance per IS 2115.

IS 2115 Key Specifications for Paving with Brick Tiles

1. Brick Tiles (Clause 5.7)

• Shall conform to IS 2690 (Part I & II) - 1975.
• Types: Machine-made (Part I) or Hand-made (Part II).

2. Laying Procedure (Clause 9.1)

• Tiles laid flat on a thin layer of mud mortar (as per Clause 5.5).
• Joint thickness: 6 mm to 15 mm.
• Mud mortar must rise vertically in joints to about 15 mm height.
• Allow 24 hours drying before grouting joints.
• Avoid tile displacement during grouting.

3. Mud Mortar (Clause 5.5)

• Used minimally to achieve a level surface.
• Provides bedding and joint filling.

4. Protection Against Dampness (Clause 6.4)

• Waterproofing required if moisture percolation is suspected.
• Waterproofing up to 150 mm above sub-floor level on walls.

Summary Table for Paving Brick Tiles

flowchart TD
    A[Prepare Mud Mortar Bed] --> B[Lay Brick Tiles Flat]
    B --> C[Ensure Joint Thickness 6-15 mm]
    C --> D[Allow 24 hrs Drying]
    D --> E[Grout Joints Carefully]
    E --> F[Waterproofing if Moisture Risk]

This ensures durable, level, and moisture-resistant brick tile paving on roofs per IS 2115.

IS 2115: Durability and Maintenance - Key Points

Durability (Clause 4.2)

• Suitable for hot, dry regions with low rainfall.
• Durability depends on maintaining protective surface layers (mud plaster or brick tiles) free from cracks.
• Cracks or dislodged joints allow water seepage, damaging the mud PHUSKA layer.
• Regular maintenance to fill cracks is essential for longevity.

Maintenance & Inspection (Clause 12.1)

Inspect the roof at these stages:

• Before spreading mud PHUSKA layer
• After mud PHUSKA layer finish
• After mud plaster finish
• After brick-tile layer finish

Protection Against Dampness (Clause 6.4)

• Waterproof roof surface against side walls up to 150 mm above sub-floor.
• Use relevant IS waterproofing standards to prevent moisture percolation.

Summary Table for Inspection Stages

Maintenance Tips

• Fill cracks promptly.
• Ensure waterproofing continuity.
• Follow IS codes for materials: burnt clay tiles, cement, sand, and mortars.

flowchart TD
    A[Start: Base Surface] --> B[Spread Mud PHUSKA]
    B --> C[Inspect Mud PHUSKA Layer]
    C --> D[Apply Mud Plaster]
    D --> E[Inspect Mud Plaster Finish]
    E --> F[Apply Brick-Tile Layer]
    F --> G[Inspect Brick-Tile Finish]
    G --> H[Regular Maintenance & Crack Filling]

This ensures durability and reduces water ingress risks per IS 2115.