Adobe Brick Calculator
Calculate the number of sun-dried adobe bricks plus soil, sand, straw, and water totals from wall area, wall thickness, brick dimensions, and joint thickness.
Brick dimensions and mortar joint
How this works
Bricks per wall area is computed by treating each brick + joint as the repeating element across the wall face, then multiplying by the number of brick layers across the wall thickness:
facialArea = (brickLength + joint) × (brickHeight + joint)
bricksFacial = wallArea / facialArea
layers = wallThickness / brickWidth
bricks = ceil(bricksFacial × layers)Per-brick allowances: 0.0045 m³ soil, 0.001 m³ sand, 0.0008 m³ straw, 1.5 L water — all multiplied by the brick count.
Worked example
A wall of 80 m², thickness 0.30 m, with bricks 300 × 150 × 100 mm and a 10 mm joint:
- Facial area = 0.31 × 0.11 ≈ 0.0341 m²
- Bricks per face ≈ 80 / 0.0341 ≈ 2,346
- Layers = 0.30 / 0.15 = 2
- Total bricks ≈ 4,692 (rounded up)
- Soil ≈ 21.1 m³, sand ≈ 4.7 m³
- Straw ≈ 3.8 m³, water ≈ 7,038 L
Sources
- Typical adobe brick workshop allowances (per-brick volume of soil, sand, straw, water)
FAQ
What is an adobe brick?
An adobe brick is a sun-dried block of clay-rich soil mixed with sand, straw, and water. It is laid in courses with mud mortar to form load-bearing walls. Adobe is one of the oldest construction techniques on Earth — pyramids in Peru, mosques in Mali, and pueblos in New Mexico are all adobe.
What are typical adobe brick dimensions?
Modern handmade adobe is usually 300 mm long × 150 mm wide × 100 mm tall (the calculator's defaults), giving a brick that one person can lift. Larger machine-pressed adobes go up to 350 × 250 × 100 mm. Smaller traditional bricks for rural construction are often 230 × 110 × 75 mm. Use whatever the local mould produces.
Why do I add a mortar joint to the brick dimensions?
Each brick takes up its own size plus the joint above and beside it. If the brick is 300 × 100 mm and the joint is 10 mm, the centre-to-centre spacing is 310 × 110 mm, and the wall area divided by 310 × 110 gives the brick count for the wall face. The default joint is 10 mm, which is a thin lime or mud joint typical of careful adobe work.
How are soil, sand, straw, and water quantities estimated?
We use typical workshop allowances for stabilised adobe: 0.0045 m³ of soil, 0.001 m³ of sand, 0.0008 m³ of straw, and 1.5 L of water per brick. These figures assume sun-curing and a moderately dense soil. Always test a small batch of your local subsoil — the right ratio is the one that gives a hard, crack-free brick after a week of drying.
Should I add a wastage allowance?
Yes — plan for 5 to 10 percent wastage from breakage during transport and installation. The calculator returns the net brick count rounded up; pad the order quantity yourself for replacements. For a remote site, pad more (around 10 to 15 percent) because resupply trips are expensive.
Can adobe be used in seismic regions?
Yes, but only with extra precautions. Plain adobe has very low tensile capacity. In seismic zones (most of Nepal, north India, and Pakistan), use a continuous reinforced concrete or timber ring beam at the top of every storey, internal vertical bamboo or steel reinforcing at corners and openings, and a maximum height-to-thickness ratio of 8. Consult a structural engineer for any habitable structure.