📐 Module 3: Complete Concrete Estimation (including formwork & B.B.S.) & DSR Based BOQ
🎓 Step‑by‑step guide | Trapezoidal footing · Column · Beam · Slab | Formwork + Bar Bending Schedule (BBS) principles | CPWD DSR 2023 rates
📲 In this Module 3, I have found the quantities between C1–C2 and C5–C6
✅ Concrete, formwork and reinforcement (preliminary) for footing, column, beam, slab – all included.
📝 The remaining quantities (other spans, extra footings, etc.) you can practice on your own.
🚀 Join the WhatsApp Channel for the full Excel file, drawing‑based exercises, and BBS templates!
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✅ Concrete, formwork and reinforcement (preliminary) for footing, column, beam, slab – all included.
📝 The remaining quantities (other spans, extra footings, etc.) you can practice on your own.
🚀 Join the WhatsApp Channel for the full Excel file, drawing‑based exercises, and BBS templates!
📌 Project Data (Imperial → Metric)
✅ Footing base: 4’9″ × 4’6″ → 1.4478 m × 1.3716 m | Bottom thk = 9″ (0.2286 m)
✅ Sloped part height = 12″ (0.3048 m) | Top landing = 1’3″×1’9″ (0.3810 m × 0.5334 m)
✅ Column: 9″ × 15″ (0.2286 × 0.3810 m) , height = 3.5 m
✅ Beams: 9″ × 15″ (0.2286 × 0.3810 overall depth) – clear spans: B1=9’9″(2.9718m), B5=9′(2.7432m), B14=11’6″(3.5052m), B18=12′(3.6576m)
✅ Slab clear area: 9’9″ × 12’6″ = 2.9718 m × 3.8100 m , thickness = 125 mm (0.125 m)
✅ Steel density = 7850 kg/m³
✅ Footing base: 4’9″ × 4’6″ → 1.4478 m × 1.3716 m | Bottom thk = 9″ (0.2286 m)
✅ Sloped part height = 12″ (0.3048 m) | Top landing = 1’3″×1’9″ (0.3810 m × 0.5334 m)
✅ Column: 9″ × 15″ (0.2286 × 0.3810 m) , height = 3.5 m
✅ Beams: 9″ × 15″ (0.2286 × 0.3810 overall depth) – clear spans: B1=9’9″(2.9718m), B5=9′(2.7432m), B14=11’6″(3.5052m), B18=12′(3.6576m)
✅ Slab clear area: 9’9″ × 12’6″ = 2.9718 m × 3.8100 m , thickness = 125 mm (0.125 m)
✅ Steel density = 7850 kg/m³
📐 Slab drawing & reinforcement detail
🏗️ Footing & column cross-section
📏 Footing layout & positioning
📌 Step A – How to Find Trapezoidal / Sloped Footing (F1) Quantities
📐 Concrete = Base portion + Sloped frustum | Formwork only for bottom | Steel thumb rule 0.6% (preliminary; final BBS required)
| Component | Formula / Description | Value | Unit |
|---|---|---|---|
| Base plate concrete | L×B×thk = 1.4478×1.3716×0.2286 | 0.454 | m³ |
| Sloped frustum | (H/3)×(A₁+A₂+√(A₁A₂)) = 0.1016×2.824 | 0.287 | m³ |
| Total Concrete | 0.454+0.287 | 0.741 | m³ |
| Formwork (bottom) | 2×(L+B)×thk = 2×2.8194×0.2286 | 1.289 | m² |
| Steel (preliminary 0.6%) | 0.741×0.006×7850 | 34.9 | kg |
📌 Step B – How to Find Column (C1) Quantities
📐 Column 9″×15″ (0.2286×0.3810m), height 3.5m | Steel % = 1.5% (preliminary)
| Component | Formula | Value | Unit |
|---|---|---|---|
| Concrete | 0.2286×0.3810×3.5 | 0.305 | m³ |
| Formwork | 2×(0.2286+0.3810)×3.5 | 4.267 | m² |
| Steel (1.5%) | 0.305×0.015×7850 | 35.9 | kg |
📌 Step C – How to Find Beam Quantities (B1, B5, B14, B18)
⚠️ Net beam depth = 0.381m – 0.125m (slab) = 0.256 m | Steel @ 1.0%
| Beam | Clear span (m) | Concrete (m³) | Formwork 3 sides (m²) | Steel (kg) |
|---|---|---|---|---|
| B1 (C1–C2) | 2.9718 | 0.1740 | 2.201 | 13.66 |
| B5 (C5–C6) | 2.7432 | 0.1606 | 2.032 | 12.61 |
| B14 | 3.5052 | 0.2052 | 2.596 | 16.11 |
| B18 | 3.6576 | 0.2141 | 2.709 | 16.81 |
| Total | 0.754 m³ | 9.538 m² | 59.2 kg |
📌 Step D – How to Find Slab (S1) Quantities
📐 Slab area 2.9718×3.8100 m, thickness 0.125 m | Steel 1.0%
| Component | Formula | Value | Unit |
|---|---|---|---|
| Formwork area | 2.9718×3.8100 | 11.3226 | m² |
| Concrete volume | Area×0.125 | 1.415 | m³ |
| Steel (1.0%) | 1.415×0.01×7850 | 111.1 | kg |
📊 Quantity Summary – Ready for BOQ
| Item | Concrete (m³) | Formwork (m²) | Steel (kg) – preliminary |
|---|---|---|---|
| Footing (F1) – each | 0.741 | 1.289 | 34.9 |
| Column (C1) – each | 0.305 | 4.267 | 35.9 |
| Beams (4 nos – B1,B5,B14,B18) | 0.754 | 9.538 | 59.2 |
| Slab (S1) | 1.415 | 11.323 | 111.1 |
| TOTAL (all items) | 3.215 m³ | 26.417 m² | 241.1 kg |
💰 DSR Based Costing (CPWD DSR 2023, Vol.1)
📖 Base rates (₹) – exclude GST, location index, overhead. Use BBS for final steel quantity.
| S.No | DSR Code | Description | Unit | Qty | Rate (₹) | Amount (₹) |
|---|---|---|---|---|---|---|
| 1 | 5.1.2 | RCC M20 in footings | m³ | 0.741 | 9,380 | 6,951 |
| 2 | 5.2.2 | RCC M20 in columns | m³ | 0.305 | 11,410 | 3,480 |
| 3 | 5.3 | RCC M20 beams & suspended floors | m³ | 0.754 | 11,620 | 8,761 |
| 4 | 5.3 | RCC M20 slabs & roofs | m³ | 1.415 | 11,620 | 16,442 |
| 5 | 5.9.1 | Formwork – foundations | m² | 1.289 | 292 | 376 |
| 6 | 5.9.6 | Formwork – columns | m² | 4.267 | 680 | 2,902 |
| 7 | 5.9.3 | Formwork – beams | m² | 9.538 | 605 | 5,770 |
| 8 | 5.9.3 | Formwork – slab | m² | 11.323 | 605 | 6,850 |
| 9 | 5.22.1 | Steel reinforcement Fe500 (preliminary) | kg | 241.1 | 65 | 15,670 |
| Subtotal → | ₹ 67,202 | |||||
🔧 How to reach final tender price (metro city example)
▪ Location index 1.08 → ₹72,578 | GST 18% → ₹13,064 | OH&P 15% → ₹10,887
▪ 📌 Estimated Contract Value ≈ ₹96,529 (basic DSR + index + GST + OH&P)
▪ Location index 1.08 → ₹72,578 | GST 18% → ₹13,064 | OH&P 15% → ₹10,887
▪ 📌 Estimated Contract Value ≈ ₹96,529 (basic DSR + index + GST + OH&P)
📐 Important Notes on Formwork & Bar Bending Schedule (BBS)
- Formwork: Measured in m² of contact area. For beams – three sides (bottom + two vertical faces). For slab – gross area minus beam top area when cast together.
- Bar Bending Schedule (BBS): The steel quantities shown above are preliminary thumb‑rule estimates. For final BOQ and tenders, always prepare a detailed BBS from structural drawings to include overlaps, bends, development length, and wastage. BBS gives exact length, shape, and weight of each bar.
- Concrete cover: Not deducted from volume – standard practice as per IS 1200.
🧾 BOQ for concrete work (with formwork & steel – preliminary)
| S.No | DSR Code | Description | Unit | Qty | Base Rate (₹) | Adjusted* (₹) | Amount (₹) |
|---|---|---|---|---|---|---|---|
| 1 | 5.1.2 | RCC M20 footings | m³ | 0.741 | 9,380 | 10,130 | 7,506 |
| 2 | 5.2.2 | RCC M20 columns | m³ | 0.305 | 11,410 | 12,323 | 3,758 |
| 3 | 5.3 | RCC M20 beams+slabs | m³ | 2.169 | 11,620 | 12,550 | 27,219 |
| 4 | 5.9.1 | Formwork footing | m² | 1.289 | 292 | 315 | 406 |
| 5 | 5.9.6 | Formwork column | m² | 4.267 | 680 | 734 | 3,132 |
| 6 | 5.9.3 | Formwork beams+slab | m² | 20.861 | 605 | 653 | 13,622 |
| 7 | 5.22.1 | Steel reinforcement (preliminary) | kg | 241.1 | 65 | 70 | 16,877 |
| Total (incl. location index 1.08 + 18% GST) | ₹ 72,520 | ||||||
*Adjusted rate includes location index 1.08 & 18% GST. Overhead/profit not included. For final steel, replace with BBS quantities.
📖 Important Note about DSR (Delhi Schedule of Rates) & BBS
DSR: Official CPWD rate document for Delhi. For BOQ: identify correct code → match unit → apply depth/height extras → add location index → add GST & overheads.
Bar Bending Schedule (BBS): The steel quantities here are thumb‑rule estimates. In professional practice, prepare a detailed BBS from structural drawings to get exact cutting lengths, number of bars, and weight. BBS is mandatory for tenders and final billing.
📎 Download DSR Vol.1 (CPWD) →
💡 Always use latest DSR (2023) and prepare BBS for accurate reinforcement cost.
DSR: Official CPWD rate document for Delhi. For BOQ: identify correct code → match unit → apply depth/height extras → add location index → add GST & overheads.
Bar Bending Schedule (BBS): The steel quantities here are thumb‑rule estimates. In professional practice, prepare a detailed BBS from structural drawings to get exact cutting lengths, number of bars, and weight. BBS is mandatory for tenders and final billing.
📎 Download DSR Vol.1 (CPWD) →
💡 Always use latest DSR (2023) and prepare BBS for accurate reinforcement cost.
❓ Frequently Asked Questions (FAQs)
📌 Q1: DSR vs SOR – which to use?
DSR for Delhi; use state SOR for other states. For benchmarks, DSR is widely accepted.
📏 Q2: Why deduct slab thickness from beam depth?
Monolithic casting – slab occupies top of beam. Net depth avoids double counting (IS 1200).
🧾 Q3: How to prepare BOQ from DSR?
Takeoff quantities → match DSR code/unit → multiply by base rate → apply index/GST/OH&P → sum.
🛠️ Q4: What is a Bar Bending Schedule (BBS) and why do I need it?
BBS is a detailed list of reinforcement bars with shape, length, and weight. It is essential for accurate steel estimation, procurement, and site fabrication – thumb rules are only for preliminary checks.
📊 Q5: Is formwork always in m² as per DSR?
Yes, for most RCC items. Codes differ: 5.9.1 (foundations), 5.9.6 (columns), 5.9.3 (beams/slabs).
🚀 Want the full Excel file, BBS template, and practice remaining quantities?
We calculated C1–C2 & C5–C6. The rest is for you to practice. Join the channel for more!
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