Inputs
Enter wall geometry, bed joint thickness, and material assumptions.
Example data table
Sample inputs and typical results for quick reference.
| Wall L | Wall H | Thickness | Unit H | Bed joint | Wastage | Volume (m3) | Mass (kg) |
|---|---|---|---|---|---|---|---|
| 10 m | 3 m | 230 mm | 75 mm | 10 mm | 7% | 0.092 | 193 |
| 18 m | 3.6 m | 115 mm | 75 mm | 12 mm | 10% | 0.104 | 218 |
Values are illustrative and will vary by workmanship and profile.
Formula used
- Course module: unit_height + bed_thickness
- Courses (conservative): ceiling(wall_height / course_module)
- Bed joints counted: courses + 1
- Total bed joint area: wall_length * wall_thickness * bed_joints
- Bed joint volume (raw): total_area * bed_thickness
- Volume with wastage: raw_volume * (1 + wastage/100)
- Mortar mass: volume_with_wastage * density
- Bags needed: mortar_mass / bag_weight
How to use this calculator
- Enter wall length, height, and thickness with correct units.
- Enter unit height and the intended bed joint thickness.
- Set mortar density and a wastage percentage for losses.
- Optionally add cost per bag or cost per m3.
- Click Calculate to see volume, mass, and bags.
- Use Download buttons to export CSV or PDF.
Professional article: bed joint planning for masonry
1) Why bed joints matter
Bed joints are the horizontal mortar layers that level each course and help distribute load across the wall thickness. Consistent thickness improves alignment, reduces point stresses, and supports reliable bond between units. When thickness varies, the wall can develop uneven bearing and local cracking under service loads.
2) The practical thickness range
On site, bed joint thickness is usually controlled by unit tolerances, workmanship, and the wall’s line and level requirements. Thicker joints may compensate for irregular units but increase shrinkage risk and material use. Thinner joints reduce volume but demand better unit quality and laying control.
3) Linking wall geometry to volume
Mortar demand is governed by wall length, wall thickness, and the number of bed layers. This calculator estimates courses from wall height divided by the course module (unit height plus joint thickness). It then counts bed joints as courses plus one, which is a conservative approach for planning and procurement.
4) Wastage and density considerations
Wastage accounts for spillage, board losses, rework, and variation in finishing. Adding a modest percentage can prevent shortfalls that interrupt laying. Density converts volume into mass for bagged materials. If using site-mixed mortar, density still helps translate volume into batching and delivery quantities.
5) Costing options for different workflows
You can estimate cost using a cost-per-bag value (useful for bagged mortar or cement-based products) or a cost-per-cubic-meter value (useful for ready mix or bulk supply). Enter either option, or both, to compare procurement strategies and reduce budget uncertainty.
6) Example data and interpretation
Example input: wall length 10 m, wall height 3 m, wall thickness 230 mm, unit height 75 mm, bed joint 10 mm, density 2100 kg/m3, wastage 7%. Typical output is about 0.092 m3 of mortar with wastage and roughly 193 kg, helping you size deliveries and labor.
7) Quality checks before ordering
Confirm the unit height used matches your selected block/brick, and that thickness reflects the actual wall (single leaf, cavity, or solid). If joints are intentionally varied (bond beams, level changes, or detailing), run separate calculations and sum results for a more robust plan.
FAQs
1) Does this include vertical joints?
No. This tool focuses on horizontal bed joints only. If you need a full mortar estimate, add an allowance for vertical joints based on unit length, joint width, and bond pattern.
2) Why are bed joints counted as courses plus one?
It provides a conservative planning count that includes a base layer and the layers between courses. Site details may differ, but this approach reduces the risk of under-ordering.
3) What wastage percentage should I use?
Common allowances range from 5% to 15% depending on access, supervision, and rework. Use higher values for complex geometry, hot weather, or less experienced crews.
4) Which mortar density is appropriate?
Use the product data if available. For general planning, typical wet mortar density is often around 2000–2200 kg/m3, but mixes and additives can change this.
5) Should I use cost per bag or cost per m3?
Use cost per bag for bagged materials and cost per m3 for bulk or delivered mortar. Enter both if you want an instant comparison of two supply methods.
6) How do I handle different wall thickness sections?
Run the calculation separately for each thickness or wall segment, then add the volumes. This is more accurate than using a single average thickness for mixed walls.
7) Can I rely on this for final procurement?
Use it for strong planning and budgeting, then validate with drawings, detailing, and site conditions. Special features like ring beams or steps may require separate allowances.
Accurate bed joint estimates reduce delays and waste significantly.