Structured lessons that make math stick.
Complete reference tables for concrete mix quantities, mortar, brickwork, blockwork, screeds, and render — with a live material quantity calculator. All figures checked against UK standards and supplier data.
Dry material requirements per 1 m³ of finished concrete, by mix ratio and grade. All figures include the 1.54 dry-volume factor and assume 25kg bag sizes.
| Designation | Grade | Strength | Cement/m³ | 25kg Bags/m³ | Sharp Sand/m³ | 20mm Agg/m³ | Water/m³ | Typical Use |
|---|---|---|---|---|---|---|---|---|
| GEN0/GEN1 | C8/C10 | 10 N/mm² | 180–200 kg | 7–8 bags | 0.45 m³ | 0.85 m³ | 150 L | Trench fill blinding, non-structural fill |
| GEN2 | C15 | 15 N/mm² | 210–230 kg | 9 bags | 0.44 m³ | 0.83 m³ | 155 L | Unreinforced strip footings, kerb bedding |
| GEN3 | C20/25 | 20 N/mm² | 250–270 kg | 10–11 bags | 0.47 m³ | 0.78 m³ | 160 L | Domestic bases, shed floors, paths, steps |
| RC25 / ST3 | C25/30 | 25 N/mm² | 320–340 kg | 13–14 bags | 0.46 m³ | 0.75 m³ | 165 L | Standard structural — driveways, slabs, foundations |
| RC30 / ST4 | C30/37 | 30 N/mm² | 360–380 kg | 14–16 bags | 0.44 m³ | 0.72 m³ | 168 L | Beams, columns, retaining walls, bridges |
| PAV1 | C35/45 | 35 N/mm² | 380–400 kg | 15–16 bags | 0.42 m³ | 0.70 m³ | 170 L | External frost-exposed paving, driveways — air-entrained |
| PAV2 | C40/50 | 40 N/mm² | 420–450 kg | 17–18 bags | 0.40 m³ | 0.68 m³ | 172 L | Heavy-duty industrial paving, HGV loading |
| Mix Ratio (C:S:A) | Equiv. Grade | Cement/m³ | 25kg Bags | Sharp Sand/m³ | 20mm Agg/m³ | Total Dry Vol. | Application |
|---|---|---|---|---|---|---|---|
| 1 : 3 : 6 | ~C10 | 195 kg | 8 bags | 0.47 m³ | 0.93 m³ | 1.54 m³ | Mass fill, blinding, non-structural |
| 1 : 2 : 4 | ~C20 | 280–300 kg | 11–12 bags | 0.44 m³ | 0.88 m³ | 1.54 m³ | General purpose — most common domestic mix |
| 1 : 1.5 : 3 | ~C25 | 360–380 kg | 14–15 bags | 0.40 m³ | 0.80 m³ | 1.54 m³ | Structural slabs, foundations, garage floors |
| 1 : 1 : 2 | ~C30 | 440–460 kg | 18 bags | 0.33 m³ | 0.66 m³ | 1.54 m³ | High-strength structural work |
| Mix Ratio (C:Ballast) | Cement/m³ | 25kg Bags/m³ | Ballast/m³ | Ballast (850kg bags) | Grade Equiv. | Use |
|---|---|---|---|---|---|---|
| 1 : 8 | 190 kg | 8 bags | 1,520 kg | 1.8 bulk bags | ~C10 | Shed base, light paths, non-structural |
| 1 : 6 | 240 kg | 10 bags | 1,440 kg | 1.7 bulk bags | ~C15 | General purpose, garden bases, steps |
| 1 : 5 | 285 kg | 11–12 bags | 1,425 kg | 1.7 bulk bags | ~C20 | Driveways, floor slabs, footpaths |
| 1 : 4 | 330 kg | 13–14 bags | 1,320 kg | 1.6 bulk bags | ~C25 | Structural slabs, lintels, heavy-duty |
Dry materials (cement, sand, aggregate) have air voids between particles. When mixed with water, these voids collapse and the volume reduces by approximately 35%. So for 1 m³ of wet concrete you must start with 1.54 m³ of dry materials. Every calculation in this table already applies this factor — but never skip it when doing your own sums.
Material quantities per 1 m³ of mixed mortar, and per 1,000 bricks / 100 m² of wall, for all common UK mortar designations.
| Mix Ratio (C:S) | BS Designation | Strength Class | Cement/m³ | 25kg Bags/m³ | Building Sand/m³ | Lime (optional)/m³ | Use |
|---|---|---|---|---|---|---|---|
| 1 : 2 | M12 | 12 N/mm² | 430 kg | 17 bags | 0.86 m³ | — | Rarely used — too strong for most brickwork |
| 1 : 3 | M6 | 6 N/mm² | 320 kg | 13 bags | 0.96 m³ | — | Engineering brickwork, manholes, below DPC |
| 1 : 4 | M4 | 4 N/mm² | 255 kg | 10–11 bags | 1.02 m³ | — | General brickwork, blockwork, most walls above DPC |
| 1 : 5 | M3 | 3 N/mm² | 210 kg | 9 bags | 1.05 m³ | — | Internal blockwork, lightweight partitions |
| 1 : 1 : 6 | M4 plasticised | 4 N/mm² | 175 kg | 7 bags | 1.05 m³ | 175 kg (20kg bags: 9) | Most common UK mix — good workability, flexible joints |
| 1 : 0.5 : 4.5 | M6 | 6 N/mm² | 225 kg | 9 bags | 1.01 m³ | 113 kg (20kg bags: 6) | Stronger lime-gauged mix, exposed locations |
| 1 : 6 (with plasticiser) | M2–M4 | 2–4 N/mm² | 175 kg | 7 bags | 1.05 m³ | + plasticiser admixture | Internal walls, non-loadbearing partitions |
| Mix | Mortar Volume/1,000 bricks | Cement (25kg bags) | Building Sand | Bricks/m² (single leaf) | Notes |
|---|---|---|---|---|---|
| 1 : 3 | 0.65 m³ | 13 bags | 0.63 m³ (≈ 1.1t) | 60 | Engineering / below DPC only |
| 1 : 4 | 0.65 m³ | 10 bags | 0.66 m³ (≈ 1.1t) | 60 | Most common above-DPC mix |
| 1 : 5 | 0.65 m³ | 8 bags | 0.68 m³ (≈ 1.1t) | 60 | Internal / sheltered locations |
| 1 : 1 : 6 | 0.65 m³ | 7 bags | 0.68 m³ (≈ 1.1t) | 60 | + 5–6 bags lime — flexible, forgiving |
For every 1,000 standard UK bricks (215×102.5×65mm) with 10mm joints using a 1:5 mix, you need approximately 120 kg of cement (5 × 25kg bags) plus 0.4 m³ of building sand. This is the official Travis Perkins guide figure and is widely used by UK bricklayers as a quick site reference.
| Wall Area | Bricks Required | Mortar Volume | Cement (25kg bags) | Building Sand | Pre-mixed Bags (20kg) |
|---|---|---|---|---|---|
| 1 m² | 60 bricks | 0.039 m³ | 1 bag | 40 kg (0.025 m³) | 2–3 bags |
| 5 m² | 300 bricks | 0.20 m³ | 4 bags | 200 kg (0.13 m³) | 10–12 bags |
| 10 m² | 600 bricks | 0.39 m³ | 6 bags | 400 kg (0.25 m³) | 20–22 bags |
| 20 m² | 1,200 bricks | 0.78 m³ | 12 bags | 800 kg (0.50 m³) | 38–42 bags |
| 50 m² | 3,000 bricks | 1.95 m³ | 30 bags | 2.0 t (bulk bag ×2.4) | 95–105 bags |
| 100 m² | 6,000 bricks | 3.90 m³ | 60 bags | 4.0 t (bulk bag ×4.7) | 190–210 bags |
Mortar must use building sand (also called soft sand or bricklaying sand) — not sharp sand. Building sand has rounder particles that create a workable, adhesive mortar. Sharp sand is too coarse and creates a weak, crumbly mortar joint. Conversely, always use sharp sand for concrete, render base coats, and floor screeds — never building sand. The two are not interchangeable.
Number of bricks, blocks, and associated mortar for standard UK masonry construction.
| Wall Type | Bricks/m² | Bricks/m³ | Mortar/m² | Cement (25kg)/m² | Sand/m² | Notes |
|---|---|---|---|---|---|---|
| Half brick (102.5mm) | 60 | ~580 | 0.039 m³ | 0.6 bags | 40 kg | Single leaf — garden walls, facing, partition |
| One brick (215mm) | 120 | ~480 | 0.083 m³ | 1.3 bags | 85 kg | Full brick wall — structural, loadbearing |
| One-and-a-half brick (327mm) | 180 | ~420 | 0.125 m³ | 2.0 bags | 130 kg | Heavy structural walls, retaining, chimney |
| Rat-trap bond (215mm) | 90 | ~400 | 0.065 m³ | 1.0 bag | 67 kg | Cavity effect — insulation potential, saves ~25% bricks |
| Honeycomb sleeper wall | 45 | — | 0.022 m³ | 0.35 bags | 22 kg | Subfloor ventilation walls — 75mm gaps every 4 bricks |
| Block Type | Size (mm) | Blocks/m² | Mortar/m² | Cement (25kg)/m² | Sand/m² | Use |
|---|---|---|---|---|---|---|
| Standard dense block | 440×215×100 | 10 | 0.012 m³ | 0.18 bags | 12 kg | Inner leaf cavity, foundations, garden walls |
| Standard dense block | 440×215×140 | 10 | 0.015 m³ | 0.22 bags | 15 kg | Structural walls, retaining, extra insulation |
| Standard dense block | 440×215×215 | 10 | 0.020 m³ | 0.30 bags | 20 kg | Heavily loaded piers, retaining walls |
| Aerated / Thermalite | 600×215×100 | 7.7 | 0.008 m³ | 0.12 bags | 8 kg | Inner leaf — excellent thermal, use 1:1:6 mortar |
| Coursing / Concrete brick | 215×65×100 | 60 | 0.039 m³ | 0.6 bags | 40 kg | Matching brick coursing to block, copings |
| Wall Construction | Bricks or Blocks/lm | Mortar/lm | Cement bags/lm | Sand/lm | Approximate Weight |
|---|---|---|---|---|---|
| Half-brick wall (102mm), 2.4m high | 144 bricks | 0.094 m³ | 1.5 bags | 97 kg | ~432 kg/lm |
| Full brick wall (215mm), 2.4m high | 288 bricks | 0.200 m³ | 3.2 bags | 207 kg | ~1,008 kg/lm |
| 100mm block wall, 2.4m high | 24 blocks | 0.029 m³ | 0.45 bags | 29 kg | ~580 kg/lm |
| 140mm block wall, 2.4m high | 24 blocks | 0.036 m³ | 0.55 bags | 37 kg | ~792 kg/lm |
Material quantities per m² for all common screed and render applications used in UK construction.
| Screed Type | Mix Ratio | Thickness | Cement/m² | 25kg Bags/m² | Sharp Sand/m² | Bags per 10m² | Application |
|---|---|---|---|---|---|---|---|
| Thin bonded screed | 1:3 | 25–40mm | 13–18 kg | 0.55–0.72 | 0.025–0.040 m³ | 6–8 bags | Directly bonded over structural slab |
| Standard unbonded screed | 1:3.5 | 50mm | 18–22 kg | 0.75 | 0.050 m³ | 7–8 bags | Standard domestic — over DPM or insulation |
| Floating screed (UFH) | 1:4 | 65–75mm | 22–28 kg | 0.90–1.10 | 0.065–0.075 m³ | 9–11 bags | Underfloor heating — over 50–100mm insulation |
| Heavy-duty screed | 1:3 | 75mm | 28–32 kg | 1.15–1.30 | 0.075 m³ | 12–13 bags | Garage, workshop, heavy forklift loading |
| Self-levelling (flow screed) | Proprietary | 30–50mm | — | — | — | 1 bag = 0.015 m³ | Fast finish, UFH, large areas — pump-applied |
| Render Type | Mix Ratio | Coat | Thickness | Cement/m² | 25kg Bags/m² | Sand/m² | Notes |
|---|---|---|---|---|---|---|---|
| Scratch coat (base) | 1:3 | 1st | 10–12mm | 5–6 kg | 0.22 | 15–18 kg | Always key the surface before applying |
| Float coat | 1:4 | 2nd | 8–10mm | 3.5–4 kg | 0.15 | 14–16 kg | Main body coat — smooth or textured finish |
| Finish coat (set) | 1:2 gauged | 3rd | 3–5mm | 2–3 kg | 0.10 | 4–6 kg | Fine sand only — steel-float smooth |
| Single-coat render | 1:4 | 1 coat | 15–20mm | 8–10 kg | 0.35 | 32–40 kg | Fast application — internal walls only |
| External 2-coat system total | Mixed | 2 coats | 18–22mm total | 8–10 kg | 0.37 | 29–34 kg | Typical UK external render — scratch + float |
| Application | Mix | Cement/m² | Sand/m² | Depth | Notes |
|---|---|---|---|---|---|
| Paving slab bedding (dry mix) | 1:6 (dry) | 3 kg | 18 kg | 25–30mm | Semi-dry — "tamp and go" method |
| Kerb bedding mortar | 1:3 | 8 kg | 24 kg | 50mm | Standard kerb bed and haunch to both sides |
| Pointing — paving joints | 1:3 dry | 0.5 kg | 1.5 kg | ~20mm deep | Dry brush-in for block paving; wet point flags |
| Tile adhesive bedding | Proprietary | 4–5 kg | — | 5–10mm | 1 bag flexible adhesive ≈ 5 m² at 5mm bed |
| Concrete bed (block paving) | C20 | — | — | 100mm | 0.1 m³/m² — see concrete table for quantities |
Calculate exact material quantities for any concrete, mortar, screed, or render job — with bag counts, bulk bag estimates, and 2026 cost guide.
Enter volume in m³ for concrete / screed / render
All quantities in these tables are net calculated figures — they represent exactly the theoretical requirement with zero waste. In practice, material is lost to spillage, over-batching, absorption into dry sub-bases, slight formwork inaccuracies, and mixing losses. A 10% allowance on straightforward slabs and 15% on steps, curved walls, or complex shapes is standard UK practice. Running short mid-pour or mid-wall is always more expensive than having a small amount left over.