CHB Wall Estimation Calculator

Compliant with NSCP, ACI, ASTM, and Eurocode standards

Note: This calculator uses practical approximations based on NSCP/ACI standards. For formal design, consult the actual code provisions and a licensed structural engineer.

Project Information

Dimensions
Materials
Labor & Costs
Adjustment Factors
Help & Formulas

Openings

Reinforcement

Mortar & Plaster

Productivity Adjustment Factors

Wall Complexity:
Scaffolding Required:
Opening Complexity:

Crew Composition

Costs

5%
100%
100%
100%
15%
10%

Standards References

  • NSCP 2015: Section 418.7.3 - Lap splices
  • ACI 318-19: Chapter 25 - Splices and development length
  • ASTM C270: Standard specification for mortar
  • Eurocode 2: EN 1992-1-1 - Concrete structures
  • DPWH Blue Book: Standard specifications

Adjustment Factors Explained

Waste Factor

Accounts for material loss during construction due to cutting, breakage, or other inefficiencies. Typical values range from 5-10%.

Weather Conditions

Adjusts productivity based on weather impact. Rainy conditions may reduce productivity by 20%, while ideal conditions may increase it by 10%.

Crew Skill Level

Accounts for the experience and efficiency of the construction crew. Highly skilled crews can be 30% more productive than inexperienced ones.

Site Access Difficulty

Considers how easy or difficult it is to access the construction site. Limited access can reduce productivity by up to 20%.

Overhead

Covers indirect costs like supervision, tools, equipment, and administrative expenses. Typically ranges from 10-20% of direct costs.

Profit Margin

The contractor's profit added to the project cost. Typically ranges from 10-20% of the total cost.

Calculation Formulas

Wall Area Calculation
Net Wall Area = (Length × Height) - (Door Area + Window Area)

Where Door Area = Number of Doors × Door Width × Door Height

Window Area = Number of Windows × Window Width × Window Height

CHB Quantity Calculation
CHB Quantity = Ceiling(Net Wall Area / 0.08)

Standard CHB size is 0.4m × 0.2m = 0.08m² per piece

Mortar Calculation
Mortar Volume = Net Wall Area × CHB Thickness × 0.25

25% of wall volume is estimated to be mortar for joints

Cement Calculation
Cement Bags = Mortar Volume × (Cement Part / Total Parts) × Cement Factor

Cement factor varies by mix ratio (typically 9-12 bags per m³)

Sand Calculation
Sand Volume = Mortar Volume × (Sand Part / Total Parts)

For 1:4 mix ratio, sand part is 4 of 5 total parts

Rebar Calculation
Vertical Bars = Ceiling(Length / Vertical Spacing) + 1 Horizontal Bars = Ceiling(Height / (0.2 × Horizontal Layers))

Standard CHB height is 0.2m per course

Plaster Calculation
Plaster Volume = (Net Wall Area × Sides × Thickness) + (Opening Perimeter × Reveal Width × Thickness)

Accounts for both main wall surface and opening reveals

Labor Calculation
Labor Days = Net Wall Area / (Productivity Rate × Weather Factor × Crew Skill × Site Access)

Adjusted for various productivity factors

Calculation Results

Enter wall dimensions and click Calculate to see results

Wall Visualization

CHB Blocks
Openings
Rebar

Bill of Quantities

Calculation required to generate BOQ