Estimating brickwork for walls is a core skill in construction, assuring the accurate material planning and cost control. This article provides a comprehensive, step-by-step procedure to calculating the number of bricks, mortar and other materials requirements for wall construction. It covers key concepts, measurements and practical considerations for beginners and professionals alike.
Step 1: Understand the Wall Specifications
Before prepare the estimate gather detailed specifications of the wall. This includes:
Dimensions of the wall : Length, height and thickness of the wall (e.g., half-brick, one-brick, or one-and-a-half-brick thick).
Type of Brick used : Standard bricks (e.g., 190mm x 90mm x 90mm in metric systems) or modular bricks vary in size, affecting calculations.
Mortar Joints: Typically 10mm thick, but confirm as this impacts brick quantity.
Openings: Doors, windows or vents that reduce the brickwork area.
Type of wall : Load-bearing, partition or boundary walls may have different construction methods.
For example, a standard brick wall in the UK uses bricks measuring 215mm x 102.5mm x 65mm with 10mm mortar joints, resulting in a nominal size of 225mm x 112.5mm x 75mm.
Accurately measure the wall’s length, height, and thickness. Use a tape measure or laser device for precision. For irregular walls, break them into smaller rectangular sections.
Length and Height: Measure in meters for metric calculations or feet for imperial.
Thickness: Common thicknesses are:
Half-brick wall: ~100mm (one brick length).
One-brick wall: ~215mm (two bricks side by side).
One-and-a-half-brick wall: ~325mm.
Openings: Measure the dimensions of doors, windows, or other openings to subtract from the total area.
Example: A wall is 5m long, 3m high, and one brick thick (215mm). It has a window of 1m x 1m.
Compute the gross wall area by multiplying length by height. Then, subtract the area of openings to get the net brickwork area.
Example Calculation:
Gross Area = 5m × 3m = 15m².
Window Area = 1m × 1m = 1m².
Net Area = 15m² − 1m² = 14m².
For multi-layered walls (e.g., cavity walls), calculate each face separately if both require brickwork.
The number of bricks per square meter depends on the brick size and mortar joint thickness. For standard UK bricks (215mm x 102.5mm x 65mm with 10mm joints):
Nominal Brick Size (including mortar): 225mm x 112.5mm x 75mm.
Area of One Brick Face: 225mm × 75mm = 0.225m × 0.075m = 0.016875m².
Bricks per Square Meter: 1 ÷ 0.016875 ≈ 59.26 (round up to 60 bricks/m² for simplicity).
For half-brick walls, this is the direct count. For thicker walls, multiply by the number of brick layers (e.g., one-brick wall = 2 layers, so 120 bricks/m²).
Example: For a one-brick-thick wall, use 120 bricks/m².
Multiply the net wall area by the number of bricks per square meter.
Example:
Add a wastage factor (typically 5-10%) to account for breakage, cutting, or errors.
Wastage (10%) = 1,680 × 0.1 = 168 bricks.
Total Bricks Required = 1,680 + 168 = 1,848 bricks.
Mortar is needed for joints between bricks. A standard 10mm joint is assumed. Mortar is typically a mix of cement and sand (e.g., 1:4 ratio).
Add 10-15% for wastage and uneven surfaces:
For a 1:4 cement-sand mix:
Convert volumes to practical units:
Cement: 1m³ ≈ 1,440kg (density of cement). So, 0.098m³ × 1,440 ≈ 141kg (approx. 6 bags of 25kg cement).
Sand: 0.391m³ (order slightly more, e.g., 0.4m³, as sand is sold in cubic meters).
Different wall types affect estimates:
Cavity Walls: Two half-brick walls with a gap. Calculate each leaf separately (e.g., 60 bricks/m² per leaf).
Reinforced Walls: May require additional materials like steel bars.
Curved or Angled Walls: Break into smaller sections or use average dimensions for estimation.
For our example (solid one-brick wall), no additional adjustments are needed.
Beyond bricks and mortar, account for:
Scaffolding: For walls over 1.5m high.
Wall Ties: For cavity walls (approx. 2.5 ties/m²).
Damp-Proof Course (DPC): For base layers to prevent moisture ingress.
Labor: Estimate based on local rates (e.g., 100-150 bricks laid per worker per day).
Double-check calculations:
Ensure measurements are accurate.
Confirm brick and mortar specifications with suppliers.
Cross-check with local standards (e.g., building codes).
Create a detailed estimate:
Bricks: 1,848.
Cement: 6 bags (25kg each).
Sand: 0.4m³.
Additional Materials: DPC, ties, etc., as needed.
Document in a table for clarity:
Material | Quantity | Unit |
|---|
Bricks | 1,848 | Nos. |
Cement | 141kg (6 bags) | Bags |
Sand | 0.4 | m³ |
Source Materials: Contact local suppliers for brick types and prices.
Site Conditions: Uneven terrain or restricted access may increase labor time.
Seasonal Factors: Rain or extreme temperatures can affect mortar curing, so plan accordingly.
Software Tools: Use estimation software (e.g., Excel, Plan Swift) for complex projects.
Ignoring Openings: Forgetting to subtract doors/windows overestimates materials.
Incorrect Brick Size: Always confirm local brick dimensions.
Underestimating Wastage: Always include a 5-10% buffer.
Mortar Mix Errors: Verify the cement-sand ratio with the contractor.
For a 5m x 3m one-brick-thick wall with a 1m x 1m window:
Net Area: 14m².
Bricks: 1,848 (including 10% wastage).
Mortar: 0.489m³ (1:4 mix, ~6 cement bags, 0.4m³ sand).
Additional: DPC, labor, scaffolding as needed.
This guide ensures accurate brickwork estimation, minimizing waste and cost overruns. Adjust calculations based on local standards and project specifics.
.png)
.png)
Comments
Post a Comment