Brickwork Quantity Calculator: Bricks per M2, Mortar Mix Ratios and Waste Allowances

Quick Answer: Standard UK metric bricks (215 × 102.5 × 65 mm) lay at 60 bricks per square metre for half-brick (single-skin) walls and 120 per square metre for one-brick (double-skin) walls. Mortar consumption is approximately 0.022 m³ per square metre of half-brick wall, or roughly 1 tonne of mortar per 1,000 bricks. Add 5–10% waste for new builds and 10–15% for cuts-heavy work; mortar mix is typically 1:1:6 OPC:lime:sand for cavity wall, 1:5 with plasticiser for general use.

Summary

The bricklayer's basic ratio — 60 bricks per square metre on half-brick — has been stable since the 1970s when metric coordinating brick dimensions were standardised. The figure includes the mortar joint (10 mm bed, 10 mm perpend) and assumes courses laid to gauge. Real-world deviations come from waste (cuts, breakages, dropped bricks), wall thickness (single-skin vs cavity), and special configurations (dog-tooth, soldier courses, heading courses).

Mortar quantity tracks brick consumption almost linearly: ~1 tonne per 1,000 bricks for typical cavity work, slightly less for half-brick fence walls, more for mass-brick walls (common in chimneys and arches). Mix ratio depends on exposure: 1:1:6 OPC:lime:sand for cavity walls, 1:1:5 for solid walls in driving rain, 1:0.5:4 for chimneys and copings, 1:5 with plasticiser as the modern site-mix shortcut.

For estimators the core check is whether the takeoff drawing accurately separates half-brick from one-brick walls, includes openings (subtract them) and reveals (add them back at one-third bond), and reflects the actual block above DPC vs brick below. For homeowners reading this looking up "how many bricks for a 5m wall" — the calculator below gives a workable estimate, but a builder will always quote with measurements taken on site.

Key Facts

• Standard UK metric brick — 215 × 102.5 × 65 mm; nominal coordinating size 225 × 112.5 × 75 mm including 10 mm joints.
• Bricks per square metre — 60 for half-brick; 120 for one-brick (cavity wall both leaves combined); 180 for one-and-a-half brick.
• Mortar consumption — approximately 0.022 m³ per m² of half-brick wall (laid joints); 0.044 m³ per m² of one-brick.
• Mortar weight per m³ — 1,800–2,000 kg/m³ depending on aggregate.
• Bag yields — 25 kg cement bag at 1:5 mix yields approximately 0.05 m³ of mortar (60 kg total weight); 1 tonne of dry mix yields approximately 0.55 m³ of mortar.
• Waste allowance — 5% for straightforward elevation; 10% for cuts-heavy (gable returns, openings); 15% for ornamental brickwork.
• Bricklayer's daily output — typical 350–500 bricks per day on standard cavity wall; 600+ on long straight runs.
• Brick types — facing (£0.50–£3.00 each), engineering (£0.60–£1.50), common (£0.30–£0.80), reclaimed (£1.50–£8.00).
• Cavity wall wall ties — typically 4 ties per m² of wall area at 900 mm horizontal × 450 mm vertical centres (BS EN 845-1).
• Wall tie length — 200–225 mm for 100 mm cavity; 250–275 mm for 150 mm cavity.
• Thermal performance — solid 220 mm brick wall U-value approximately 1.5 W/m²K; cavity wall with 100 mm insulation 0.18–0.22 W/m²K.
• Bond patterns — Stretcher (most common), Flemish (alternating headers and stretchers), English (alternating courses), English Garden Wall (3 stretcher courses to 1 header).
• DPC level — minimum 150 mm above ground; typically 2 brick courses = 150 mm above ground level.

Quick Reference Table

Detailed Guidance

Brick quantity calculation step by step

For a typical cavity wall (two leaves of half-brick, separated by a cavity):

1. Measure wall area. Take elevation length × height. Subtract opening areas (windows, doors). Add back any reveals (the brickwork that returns into the opening on the inside of the cavity).
2. Apply per-m² figure. For cavity wall, both leaves combined = 120 bricks per m² (60 outer + 60 inner). For half-brick fence wall, 60 per m².
3. Add waste. 5% for simple work (straight runs, no special features); 10% for typical domestic (with openings, cuts at angles, returns); 15% for arches, dog-tooth, ornamental.

Example: 8 m × 2.4 m external wall with one window opening 1.5 m × 1.2 m.

• Wall area: 8 × 2.4 = 19.2 m²
• Window opening: 1.5 × 1.2 = 1.8 m²
• Net wall area: 19.2 − 1.8 = 17.4 m²
• Reveals: ~0.6 m × 4 sides × 100 mm thick = ~0.24 m² (brick reveals, half-brick)
• Effective half-brick area: 17.4 m² (outer leaf) + 17.4 m² (inner leaf) + 0.24 m² (reveals)
• Total bricks (no waste): 35.04 × 60 = 2,102 bricks
• With 10% waste: 2,102 × 1.10 = 2,313 bricks
• Round to delivery pack: 2,400 bricks (typical pallet 400-500 bricks).

Mortar quantity calculation

Mortar quantity follows brick quantity approximately linearly:

• Half-brick wall: 0.022 m³ mortar per m² of wall
• One-brick wall (cavity, both leaves): 0.044 m³ per m²
• Solid one-brick wall: 0.044 m³ per m²

Example continued: 17.4 m² cavity wall × 0.044 = 0.766 m³ of mortar.

Convert to material:

• 1 m³ mortar = approximately 1,900 kg
• 1 m³ mortar at 1:5 mix = ~265 kg cement + 1,635 kg sand
• 1 m³ mortar at 1:1:6 mix = ~205 kg cement + 110 kg hydrated lime + 1,635 kg sand

For 0.766 m³:

• Cement: 200 kg (eight 25 kg bags) at 1:5 with plasticiser
• Sand: 1,250 kg (one tonne bag) at 1:5
• Plasticiser: 1 L per 25 kg cement (8 L total)

Bond patterns and quantity adjustments

Stretcher bond — most common; all bricks laid lengthwise. Standard 60 bricks/m² applies.

Flemish bond — alternating headers (short ends visible) and stretchers in same course. Solid wall only (header course bonds the two leaves). Increases brick count by ~10% due to more cuts and headers.

English bond — alternating courses of headers and stretchers. Solid wall, traditional pre-1900s. Increases brick count by ~10%.

English Garden Wall bond — three stretcher courses to one header course. Decorative variation; minimal quantity impact.

Soldier courses — bricks laid vertically as a feature row (e.g. above lintel). Count: 13 bricks per m run.

Mortar mix selection

Mix selection follows BS 5628 / BS EN 1996-2 exposure categories:

Severe exposure — chimneys above roof, parapets, copings, free-standing garden walls, retaining walls. Use 1:0.5:4 (M12 designation in BS EN 1996-2).

Moderate to severe exposure — solid walls in driving rain areas (north-west England, west coast Wales, Scotland). Use 1:1:5 (M6).

Standard exposure — typical cavity walls in average UK conditions. Use 1:1:6 (M4) or 1:5 with plasticiser equivalent.

Sheltered exposure — internal partitions, well-protected walls. Use 1:2:9 (M2) or 1:6 with plasticiser equivalent.

Lime serves multiple functions: improved workability, autogenous healing of micro-cracks, slower set time allowing better adjustment. Plasticiser is a modern site-mix shortcut that gives similar workability without lime, but without the autogenous healing.

Wall ties for cavity walls

BS EN 845-1 specifies wall tie requirements:

• Spacing: 900 mm horizontal × 450 mm vertical, giving 4 ties per m².
• Length: 200–225 mm for 100 mm cavity (insulation up to 100 mm).
• Length: 250–275 mm for 150 mm cavity (insulation up to 100 mm + 50 mm air).
• Length: 275–300 mm for 150 mm cavity with 100 mm full-fill insulation.
• At openings: 600 mm horizontal × 225 mm vertical at jamb (closer spacing).
• Material: stainless steel grade 304 minimum; grade 316 for marine exposure.

DPC and damp-proof construction

The DPC course is typically 2 bricks above ground level (~150 mm). Materials:

• Pitch polymer DPC roll (most common UK domestic).
• Lead-cored bitumen DPC for higher specification.
• Engineering brick coursing as an alternative DPC in older buildings.

Below DPC, mortar mix is 1:0.5:4 (M12) for sulphate resistance and water shedding.

Reclaimed and historical bricks

Reclaimed bricks (Victorian/Edwardian Imperial) are larger:

• Typical Victorian: 230 × 110 × 70 mm — 50 bricks per m² half-brick.
• Edwardian metric-cusp: 220 × 105 × 65 mm — 55 bricks per m² half-brick.

For renovation/extension matching, count from a representative wall area; differences from standard metric can be 5-10% in quantity.

Special configurations

Arches — 50–100% extra brick consumption per m of arch length due to cuts and waste.

Dog-tooth bands — alternating bricks set at 45°; ~20% more brick than plain stretcher.

Decorative quoins — corner bricks of contrasting colour; quantity per drawing.

Plinth courses — projection at base of wall; quantity per drawing, typically 10-20% extra in those courses.

Worked example — small extension

Building an extension wall: 6 m wide × 2.6 m high, with door 0.9 m × 2.1 m.

• Wall area: 6 × 2.6 = 15.6 m²
• Door opening: 0.9 × 2.1 = 1.89 m²
• Net wall area: 15.6 − 1.89 = 13.71 m²
• Cavity wall (two leaves): 13.71 × 120 = 1,645 bricks
• Plus 10% waste: 1,810 bricks
• Round to delivery: 2,000 bricks (pallet)

Mortar:

• 13.71 × 0.044 = 0.603 m³
• At 1:1:6 mix: 124 kg cement + 67 kg lime + 985 kg sand
• Or 5 × 25 kg cement bags + 3 × 25 kg lime bags + 1 tonne sand bag

Wall ties:

• 13.71 m² × 4 = 55 ties
• Plus extra at jamb of door opening: ~6 ties
• Total: 61 ties; round to box of 100.

Consumer-facing question — "how many bricks do I need for my garden wall?"

For a single-skin garden wall (half-brick) 6 m long × 1 m high:

• Wall area: 6 m²
• Bricks: 6 × 60 = 360 bricks
• Plus 10% waste: 396 bricks
• Round to pallet: 400 bricks
• Mortar: 6 × 0.022 = 0.132 m³ ≈ 4 × 25 kg cement bags + ~250 kg sand

Add coping or capping bricks separately at 1 cap per 215 mm of wall length = 28 caps for the 6 m wall.

Frequently Asked Questions

How accurate is the 60 bricks per m² figure?

The figure is based on standard 215 × 102.5 × 65 mm metric brick laid to 75 mm coursing (65 mm brick + 10 mm joint). Real-world variations: some bricks vary in dimension by ±2 mm, joint thickness varies 8–12 mm depending on bricklayer style, and modular brick jointing can shift the figure by 5–10%.

How much waste should I allow for matching old brick?

For matching reclaimed Victorian brick to existing work, allow 20–25% waste. Reclaimed bricks have variable dimensions and quality; cuts are slower; many bricks are unusable.

Can I mix mortar by volume on site?

Yes — site mix by volume is accurate enough for typical work. Use a clean shovel-count method: 1 cement : 5 sand for 1:5; 1 cement : 1 lime : 6 sand for 1:1:6.

What's the difference between sharp sand and building sand?

Building sand (soft sand) is fine and rounded — used in mortar for workability. Sharp sand (concrete sand) is coarser and angular — used in concrete. Mortar with sharp sand is harder to lay and harsh on the trowel.

How do I estimate mortar from cement bags?

A 25 kg bag of cement at 1:5 mix yields approximately 50 litres of mortar (0.05 m³). 1 m³ of mortar = 20 bags. For 0.5 m³, allow 10 bags + 250 kg sand.

Regulations & Standards

• BS EN 771-1 — Specification for masonry units; clay brick performance categories.

• BS EN 998-2 — Specification for mortar for masonry; types and designations.

• BS EN 1996-1-1 — Eurocode 6: Design of masonry structures; structural design rules.

• BS EN 1996-2 — Eurocode 6: Design considerations, selection of materials and execution.

• BS EN 845-1 — Specification for ancillary components; wall ties.

• BS 5628 (superseded by BS EN 1996) — Code of practice for use of masonry; legacy reference.

• NHBC Standards Chapter 6.1 — External masonry walls.

• BSI — BS EN 1996 Eurocode 6 — masonry design code.

• BDA Brick Development Association — UK brick manufacturer trade body and technical resources.

• The Mortar Industry Association — mortar mix selection guidance.

• NHBC Standards Chapter 6.1 — external masonry walls.

• mortar quantities — by mix and application — companion calculator focused on mortar volume.

• brick quantities companion calculator — alternative reference.

• decking materials and quantities — comparable trade calculator format.

• loft insulation pricing — wall insulation costs interact with cavity wall brickwork.