Estimate the number of concrete blocks required for one or more walls. Subtract doors and windows, include a waste allowance and obtain an approximate mortar estimate.
Estimate the number of concrete blocks required for a wall after subtracting doors and windows.
No doors or windows have been added. The full wall area will be calculated.
First, calculate the gross wall area by multiplying its length by its height. For several identical walls, multiply the result by the wall quantity.
Next, subtract the surface area of doors, windows and other openings.
Finally, divide the net area by the modular face area of the block, including its visible dimensions and mortar joint thickness.
General formula
Blocks = net area ÷ modular block area
Calculate the wall area by multiplying length by height. Subtract doors and windows, then divide the net area by the modular face area of the block.
The quantity depends on block dimensions and joint thickness. A nominal 40 × 20 cm block generally requires approximately 11.5 to 12.5 units per square meter.
A waste allowance of 5% to 10% is common for cuts, breakage and adjustments. Walls with many openings or details may require more.
Yes. You can add multiple openings and specify the width, height and quantity of each one.