Masonry Takeoff: openings, brick/block count and order quantity
A useful masonry takeoff goes beyond length × height. Door and window openings must be deducted, the installed brick or block module must be understood, and theoretical quantity should be separated from the final order allowance. This workflow connects drawing measurements to a practical material takeoff.
Content and method review: September 19, 2026
1. Gross area to net masonry area
Anet = L × H − Σ(Aopenings)
For multiple doors or windows, calculate each opening and add them together. A 20 ft × 9 ft wall with a 3 ft × 7 ft door and a 5 ft × 4 ft window has 180 − 21 − 20 = 139 ft² of net wall area.
2. Net area to unit count
Theoretical units ≈ Anet / Amodule
The module is the visible wall area occupied by one installed unit. For mortared masonry, using the project or manufacturer module including the intended joint can be more accurate than using the bare unit dimensions alone.
Quick unit-count reference
| Illustrative face/module | Area | Theoretical units | Note |
|---|
| 16 × 8 in | 0.889 ft² | ≈ 1.13 / ft² | Geometric example |
| 16 × 10 in | 1.111 ft² | ≈ 0.90 / ft² | Large-unit example |
| 400 × 200 mm | 0.080 m² | 12.5 / m² | Metric module example |
| 500 × 200 mm | 0.100 m² | 10.0 / m² | Metric module example |
These are geometric examples, not a product standard or purchase schedule. Verify actual unit dimensions, joint system and manufacturer data.
Worked takeoff example
Wall: 26 ft × 10 ft = 260 ft²
Door: 3 ft × 7 ft = 21 ft²
2 windows: 2 × (5 ft × 4 ft) = 40 ft²
Net area: 260 − 61 = 199 ft²
16 × 8 in geometric face: 199 / 0.889 ≈ 224 units
5% planning allowance: 224 × 1.05 = 235.2 → about 236 units
Theoretical count is not the purchase order
Corners, cut units, service penetrations, breakage, pallet quantities and installation method can change the actual order. Treat waste as a project input rather than a universal fixed percentage.
What does wall thickness change?
Wall thickness is not directly part of a single-face area calculation, but it affects wall volume, dead load, mortar or adhesive demand and the selected masonry product. Walls of different thicknesses should normally be separated in a material takeoff.
Mortar and thin-set consumption
A universal mortar-per-square-foot factor is unreliable. Unit geometry, joint thickness, hollow or solid construction, and thin-bed adhesive systems can materially change consumption. Use manufacturer coverage and the project specification for purchasing.
Six checks before ordering masonry
1 — OpeningsHave doors, windows and major penetrations been deducted?
2 — Wall typesAre different materials and thicknesses taken off separately?
3 — ModuleAre bare unit dimensions being confused with the installed module?
4 — WasteDoes the allowance reflect cuts, breakage and handling?
5 — PackagingWill the order need to be rounded to full pallets or packs?
6 — DetailsHave lintels, bond beams, columns and service shafts been checked separately?
Masonry takeoff FAQ
How many bricks or blocks are needed per square foot?
There is no universal number. Divide one square foot by the installed face/module area of the selected unit; joint dimensions and product geometry can change the result.
How do I subtract doors and windows?
Multiply width by height for each opening, add the opening areas, and subtract the total from gross wall area.
Should waste be applied before or after openings?
Deduct openings first to obtain net masonry area and theoretical units, then apply the selected material allowance.
Does wall thickness affect block count?
For a single-wythe wall with the same face module, units per area are not calculated from thickness alone. In practice, a different thickness often means a different product and module.
Why can’t mortar quantity be exact from wall area alone?
Joint thickness, unit voids, installation system and mortar or adhesive type all affect consumption. Manufacturer and specification data should govern purchasing.
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