Scope
- Class F covers all types of in situ concrete works, i.e., concrete that is mixed, transported, placed, and cured directly on site, within formwork, foundations, substructures, and superstructures.
- It includes plain (mass) concrete and reinforced concrete.
- The classification ensures clarity in measurement, pricing, and execution.
1. General Principles
- Measurement must distinguish between:
- Type of concrete (plain vs. reinforced).
- Grade/strength of concrete (e.g., C20/25, C25/30).
- Location of work (foundation, column, slab, wall, etc.).
- Shape/complexity (simple mass concrete vs. structural concrete).
- The unit of measurement is cubic metre (m³).
- Formwork and reinforcement are measured separately (Class G: Formwork, Class H: Reinforcement).
2. Sub-classifications under Class F
CESMM4 divides in situ concrete into several categories:
F1 – Mass Concrete (Plain Concrete)
- Used where no reinforcement is provided.
- Examples: blinding layers, mass foundations, levelling courses.
- Measured in m³, itemized by:
- Mix proportion / grade (e.g., C15, C20).
- Thickness and extent.
- Location (e.g., foundation, basement slab).
F2 – Reinforced Concrete
- Includes concrete that incorporates reinforcement (measured separately in Class H).
- Examples: columns, slabs, beams, walls.
- Measured in m³, with details:
- Grade (e.g., C25/30).
- Structural member (slab/beam/wall/column).
- Location (substructure/superstructure).
- Form of construction (horizontal, vertical, inclined).
F3 – Special Concrete
- Covers concrete with special properties:
- High-strength concrete.
- Lightweight concrete.
- No-fines concrete.
- Permeable or aerated concrete.
- Used in specialized structural works, bridge decks, precast in-situ joints, etc.
F4 – Surface Finishes to Concrete
- Includes trowelling, bush-hammering, ribbed finishes, or textured finishes required for appearance or bonding.
- Measured in square metres (m²).
- Example: Fair-faced concrete in architectural structures.
F5 – Cast-in Items
- Items embedded into concrete at the time of placing:
- Water stops.
- Anchor bolts.
- Inserts.
- These are measured separately with clear descriptions.
3. Measurement Rules
- Formwork and reinforcement are excluded from Class F (see Class G and H).
- Concrete is measured net volume in place, no allowance for wastage.
- Openings >0.5 m² or recesses >0.05 m³ are deducted from measurements.
- Small holes (<0.5 m²) are not deducted.
4. Information Required in Bill Descriptions
Each item of in situ concrete must state:
- Concrete grade or mix.
- Type: plain, reinforced, or special.
- Member: slab, column, beam, foundation, wall.
- Location: substructure, superstructure, below/above ground.
- Finish: fair-faced, exposed, or ordinary.
- Any embedded items or special curing methods.
5. Example BOQ Items (Class F)
- Plain concrete blinding layer, 100 mm thick, Grade C15, to foundations. (m³)
- Reinforced concrete Grade C25/30 in beams at ground floor level. (m³)
- Reinforced concrete Grade C30/37 in shear walls, below ground level. (m³)
- Lightweight reinforced concrete, slab, 200 mm thick, above ground floor. (m³)
- Fair-faced surface finish to reinforced concrete wall, 25 m². (m²)
- Cast-in water bar in expansion joint, 50 m length. (m).
✅ Summary
Class F ensures that in situ concrete is measured in a clear, structured way that reflects its grade, type, and application. Reinforcement (Class H) and formwork (Class G) are measured separately to avoid duplication.
