IS 2571 — Code of practice for laying in-situ cement concrete flooring

IS 2571: Scope and Key Specifications

Scope (Clause 2.0 & 2.1)

• Defines terms and specifications for cement concrete flooring laid over ground.
• Covers materials, mix proportions, thickness, and construction practices.

Key Tables and Specifications

1. Coarse Aggregate Grading (Clause 4.2.1.1, Table 1)

2. Concrete Floor Finish (Clause 9.2, Table 3)

Notes:

• C = Cement,

IS 2571: Definitions & Key Specifications

1. Definitions (Clause 2.0 & 2.1)

• General Terms: Standardized terms related to cement concrete flooring are defined for clarity and uniformity in interpretation.

2. Coarse Aggregate Grading (Table 4.2.1.1)

3. Recommended Concrete Floor Finishes (Table 9.2)

IS 2571: Preliminary Information and Planning for Cement Concrete Floor Finish

Key Points from Clause 3.1 (Preliminary Info)

For efficient planning, gather:

• Purpose of floor use
• Floor area
• Location & size of openings, ducts, drainage
• Sub-base/sub-floor details
• Soil type & seepage issues
• Colour/appearance requirements
• Skirting requirements
• Slope to be provided

Recommended Floor Finish Specifications (Clause 9.2, Table 3)

Coarse Aggregate Grading (Clause 4.2.1.1, Table 1)

IS 2571 - Key Materials Specifications

1. Coarse Aggregate Grading (Clause 4.2.1.1, Table 1)

• Use graded aggregates conforming to these passing percentages for nominal sizes.
• Fine aggregates and other materials should comply with relevant IS codes.

2. Mixing of Materials (Clause 7.2)

• Proper proportioning and mixing to ensure uniformity.
• Avoid use of calcium chloride with high alumina cement (Clause 2.4).

3. Cement Types (Clause 12.5)

• Ordinary, Rapid-hardening, Low heat Portland cement.
• Portland blast-furnace slag cement.
• Portland pozzolana cement.
• Follow relevant IS specifications for each type.

Summary:

• Ensure aggregate grading as per Table 1 for nominal sizes.
• Avoid harmful admixtures like calcium chloride with high alumina cement.
• Use cement types as per IS 2571 specifications.

flowchart LR
    A[Materials] --> B[Aggregates]
    B --> C[Coarse Aggregate Grading]
    B --> D[Fine Aggregate]
    A --> E[Cement Types]
    A --> F[Mixing]
    F --> G[Proper Proportioning]
    F --> H[Avoid Calcium Chloride with HAC]

For detailed testing and other material properties, refer to IS 383 and IS 456 as complementary standards.

IS 2571: Key Design Considerations for Cement Concrete Floor Finishes (Clause 9.2)

1. Recommended Floor Finish Types & Specifications (Table 3)

2. Floor Topping on Structural/Suspended Slabs

3. Aggregate Grading (Clause 4.2.1.1, Table 1)

IS 2571: Programme of Work in Relation to Floor Finish

Key Specifications & Steps

• Clause 3.1: Preliminary Information

  • Purpose of floor use
  • Floor area coverage
  • Openings, ducts, drainage outlets
  • Sub-base/sub-floor details & soil type
  • Colour/appearance requirements
  • Skirting needs
  • Floor slope design

• Clause 6.3: Marking Levels

  • Mark finished surface points and levels before starting
  • Mark slopes and outlets accurately
  • Prepare outlet openings in advance

• Clause 5.1 & Table 3: Floor Finish Types & Thickness

  • Thickness depends on load, wear, and whether topping is monolithic or separate
  • Ensure good bond between topping and base

• Clause 5.9: Finish Over Stairs

  • Mix same as topping (see Table 3)
  • Risers: 6 mm mortar finish (up to 10 mm if uneven)
  • Treads:
    • Monolithic finish ≥ 20 mm thick
    • Finish over hardened concrete ≥ 40 mm thick

Typical Thicknesses (from Table 3 summary):

Workflow Summary (Mermaid Diagram):

flowchart TD
    A[Collect Preliminary Info (Clause 3.1)] --> B[Mark Levels & Slopes (Clause 6.3)]
    B --> C[Prepare Sub-base & Outlets]
    C --> D[Select Floor Finish Type & Thickness (Clause 5.1, Table 3)]
    D --> E[Apply Floor Finish]
    E --> F[Finish Over Stairs (Clause 5.9)]

Note: Always ensure proper bonding and curing as per IS 2571 for durable floor finishes.

IS 2571: Preparatory Work for Floor Finish

Key Points from IS 2571:

• Marking Levels (Clause 6.3):

  • Before floor finishing, mark all points/levels for the finished surface.
  • Mark slopes and outlet points clearly.
  • Make outlet openings in advance.

• Planning Details (Clause 3.1):

  • Define:
    • Purpose of floor use.
    • Floor area.
    • Openings, ducts, drainage outlets.
    • Sub-base/sub-floor details.
    • Soil type and seepage issues.
    • Surface appearance and aggregate color.
    • Skirting requirements.
    • Required slope.

• Sub-base Preparation (Clauses 8.1.1 & 8.2.1):

  • Prepare sub-base as per 8.1.1.1 to 8.1.1.3 (typically involves compaction, leveling, and moisture conditioning).

Typical Preparatory Work Checklist:

Slope Provision Formula:

[ \text{Slope} = \frac{\text{Vertical Drop}}{\text{Horizontal Distance}} \quad \text{(typically 1:100 to 1:200)} ]

flowchart TD
    A[Planning & Design] --> B[Mark Levels & Slopes]
    B --> C[Prepare Sub-base]
    C --> D[Make Outlet Openings]
    D --> E[Clean Surface]
    E --> F[Start Floor Finishing]

Summary: Proper marking, sub-base preparation, and outlet provision are critical preparatory steps per IS 2571 to ensure durable and functional floor finishes.

IS 2571: Laying Concrete Flooring on Ground — Key Specifications & Formulas

1. Sub-base & Base Concrete (Clause 9.2, Table 3)

2. Mix Preparation & Placement (Clauses 7.2.2 & 8.2.2)

• Use concrete within 30 minutes of water addition.
• Sub-base must be wetted and rammed before placing base concrete.
• Base concrete is laid continuously, tamped, and finished level.
• Surface left rough to bond topping.
• After 2-3 hours, brush surface to expose coarse aggregate.

3. Recommended Mix Proportions

IS 2571 Key Points for Laying Concrete Flooring on Structural Slabs

1. Formwork & Surface Preparation (Clause 9.1.1)

• Formwork erected to finished floor thickness.
• Structural concrete deposited and consolidated below form top to allow topping thickness.
• Provide slope in structural concrete.
• Surface kept rough (not smooth) for good bond with topping.
• Remove laitance/scum while concrete is green.

2. Recommended Specifications (Clause 9.2, Table 3)

3. Important Notes

• Topping should be laid immediately after slab stiffens but still green for monolithic bond.
• For hardened slabs, prepare surface properly before topping.
• Use planks to walk on green concrete during topping placement.
• Cushioning lime concrete layer may be used under topping (Fig. 5).

4. Typical Mix Proportions

• Base Concrete: 1:3:6 or 1:4:8 (cement : fine agg : coarse agg)
• Topping: 1:2 to 3 (cement : stone aggregate ≤ 4.75 mm) or 1:2:3 for heavier traffic

5. Illustrative Concept (Monolithic Topping on Structural Slab)

flowchart TB
    A[Structural Slab - Fresh Concrete] --> B[Topping Laid Immediately]
    B --> C[Consolidation & Finishing]
    C --> D[Rough Surface for Bond]
    D --> E[Finished Floor]

References: IS 2571 Clauses 9.1.1, 9.2, 5.1.3, and Figures

IS 2571: Floor Finish Over Stairs - Key Specifications & Formulas

1. Mix for Finish (Clause 5.9)

• Use the same mix as topping (see Clause 5.1 & Table 3).
• Risers: Minimum thickness 6 mm (mortar finish), up to 10 mm if uneven.
• Treads:
  • Monolithic finish: ≥ 20 mm thick.
  • Finish over hardened concrete: ≥ 40 mm thick.

2. Surface Preparation (Clause 9.3.2)

• Clean lime concrete surface thoroughly.
• Apply neat cement slurry before topping.
• Follow layering and curing as per Clauses 8.2.3 & 8.2.4.

3. Non-Slip Finish (Clause 5.5.1)

• Use chequered pattern on ramps/stairs exposed to wet conditions.

Table Extract (Thickness of Finish Over Stairs)

Summary Diagram: Floor Finish Layers on Stairs

graph TD
  A[Structural Concrete] --> B[Surface Preparation]
  B --> C[Neat Cement Slurry]
  C --> D[Finish Layer]
  D --> E{Type of Finish}
  E -->|Riser| F[6-10 mm Mortar Finish]
  E -->|Tread Monolithic| G[≥ 20 mm Finish]
  E -->|Tread Over Hardened Concrete| H[≥ 40 mm Finish]

Note: Follow bitumen specifications and damp-proofing codes where applicable for waterproofing layers.

IS 2571: Key Points on Curing and Protection of Cement Concrete Flooring

Curing (Clause 11.1)

• Immediate Protection: After finishing, protect the surface from rapid drying by erecting barriers against wind, draught, and strong sunlight.
• Moist Curing Duration: Keep the surface continuously moist for at least 15 days using:
  • Wet gunny bags
  • 50 mm thick damp sand layer
  • Pooling water on the surface
• Traffic Restriction: No traffic during curing; allow regular traffic only after 28 days.

Surface Preparation (Clause A-1.1)

• Clean the floor surface thoroughly (remove grease/oil).
• Wet and scrub with coir/steel wire brush.
• Wash with clean water and allow drying before applying hardening solutions.

Surface Hardening (Clause 5.6)

• Optional dust reduction by applying surface hardening solutions like:
  • Sodium silicate
  • Magnesium silico-fluoride
  • Zinc silico-fluoride
• Renewal recommended every 1 year.

Summary Table: Moist Curing Methods

flowchart TD
    A[Finished Flooring Surface] --> B{Protect from rapid drying}
    B --> C[Barriers against wind/sunlight]
    B --> D[Start moist curing]
    D --> E[Wet Gunny Bags]
    D --> F[50 mm Damp Sand]
    D --> G[Pooling Water]
    E & F & G --> H[Continuous moist curing for 15 days]
    H --> I[No traffic allowed]
    I --> J[Allow traffic after 28 days]

This ensures proper hydration for strength and durability per IS 2571 standards.

IS 2571: Inspection and Testing - Key Points

1. Curing and Protection (Clause 11.1)

• Immediately after finishing, protect flooring from rapid drying (wind, sun).
• Keep surface continuously moist for at least 15 days using:
  • Wet gunny bags
  • 50 mm thick damp sand layer
  • Pooling water
• No traffic on floor during curing.
• Allow regular traffic only after 28 days.

2. Coarse Aggregate Grading (Clause 4.2.1.1)

3. Cement Concrete Floor Finishes (Clause 9.2, Table 3)

• Base thickness: Minimum 100 mm (well-compacted sub-base)
• Topping thickness: 20-25 mm
• Mix proportions:
  • Base: 1:4:8 (cement:fine aggregate:coarse aggregate)
  • Topping: 1:2 to 1:3 (cement:stone aggregate ≤4.75 mm)
• Variants for sub-base include rammed ground, hardcore, or stone ballast depending on soil conditions.

Summary Diagram of Curing Process

flowchart TD
    A[Finished Flooring Surface] --> B[Protect from Wind & Sunlight]
    B --> C[Keep Surface Moist for 15 Days]
    C --> D[Methods: Wet Gunny Bags / Damp Sand / Pooling Water]
    D --> E

IS 2571: Surface Treatment to Cement Concrete Floor Topping

Key Specifications & Formulas

• Surface Hardening Solutions (Clause 5.6):

  • Sodium silicate, magnesium silico-fluoride, zinc silico-fluoride, or proprietary compounds.
  • Applied to reduce dusting; renewal typically every 1 year.
  • Surface must be clean, dry, and free from grease/oil before application (Appendix A).
  • Cleaning: wetting, scrubbing with coir/steel brush, washing, drying.

• Concrete Floor Topping Thickness & Mix (Table 3, Clause 9.2):

• Wearing Layer (Clause 8.2.4.1):
  • Top 15 mm wearing layer of 1:2 to 3 mix, stiffer consistency.
  • Laid immediately on green under-layer, tamped, struck off, floated.
  • Surface leveled with straight-edge and spirit level; undulations corrected.
  • Finished smooth per Clause 8.1.3.2.

Summary Diagram: Surface Treatment Process

flowchart TD
    A[Clean Surface] --> B[Wet & Scrub (coir/steel brush)]
    B --> C[Wash with Clean Water]
    C --> D[Dry Surface]
    D --> E[Apply Hardening Solution]
    E --> F[Allow Absorption]