Start with wall volume
The first step is to calculate the gross wall volume from length, height and thickness.
Wall volume = Length × Height × Thickness
Openings such as doors and windows should be deducted when the problem or measurement method requires a net wall quantity.
Estimating brick quantity
Brick count depends on the actual brick dimensions and the assumed mortar joint. A useful method is to calculate the nominal volume occupied by one brick including its mortar allowance, then divide the wall volume by that nominal unit volume.
Approximate brick count = Wall volume ÷ nominal brick-with-mortar volume
Mortar
Mortar quantity is not simply the wall volume multiplied by an arbitrary percentage. A more transparent approach is to calculate the total volume of brick units plus the volume occupied by joints, then apply the selected mortar mix and dry-volume allowance.
Checklist
- Confirm brick dimensions.
- Confirm wall thickness.
- Deduct openings when required.
- State the mortar-joint assumption.
- State the wastage allowance.
- Keep wet and dry volumes clearly separated.
Brickwork estimates are sensitive to brick size and joint thickness. Always show the assumptions so another person can reproduce the quantity.