How many bricks, how much cement and steel to build a house?

Short answer: for a single-storey, two-bedroom home of 62 m² (2.5 m ceilings) with 9-inch brick outside walls and 4½-inch inside walls, the walls take about 14,000 bricks, and the mortar, plaster, footings and ground slab about 144 bags of cement (50 kg), 19 m³ (680 cft) of sand and 16 m³ (580 cft) of stone. The same home on two storeys with a gable roof takes about 31,700 bricks, 271 bags, 36 m³ of sand, 23 m³ of stone and 564 kg of steel. Draw your own plan to get your own numbers.

Step 1: measure the walls the right way

Wall quantities go wrong in two places:

• Outside walls are measured along their middle line, not the inside of the rooms: each room wall gets the wall's thickness added, half at each end. For a 4 × 3 m room with 9-inch walls that is 14 m inside but 14.93 m along the middle.
• A wall between two rooms is counted once. If you add up every room's walls, the shared walls come in twice.

Doors and windows come out, and under a gable roof the two triangles of end wall are added: for a house 7.3 m deep at a 30° pitch, 15.4 m² of extra brickwork.

Step 2: bricks and mortar

The Pakistani building brick is 9 × 4⅜ × 2 11/16 in (228 × 111 × 68 mm) laid with ⅜ in joints. That is 54 bricks per m² for each leaf, so a 9-inch wall (two leaves) takes about 108 per m², the local "13½ bricks per cubic foot". Add 5 % for breakage.

The mortar fills the joints between the bricks and between the leaves, plus a little extra. A 1 : 6 mix (cement : sand) is turned into cement and sand with a dry-volume factor of 1.33, because loose sand and cement shrink when they are mixed with water.

Step 3: plaster

Plaster goes on the outside face of the outside walls, both faces of every inside wall and, usually in Pakistan and India, the ceilings: 12 mm of 1 : 4, plus 10 %.

Step 4: footings and slabs

• Strip footings under every ground-floor wall: length along the middle line × 0.6 m wide × 0.3 m deep, in 1 : 3 : 6 concrete.
• Ground slab: the floor area × 100 mm, 1 : 3 : 6.
• Slabs between floors (and under a flat roof): 125 mm of 1 : 2 : 4, with 10 mm bars every 150 mm both ways. Stair holes are left out.

Concrete uses a dry-volume factor of 1.54. Steel is the slab area × 2 ÷ spacing × 0.617 kg per metre for a 10 mm bar, plus 10 % for laps: about 9 kg per m² of slab.

The example in numbers

For the single storey the cement splits into 31 bags for the brick mortar, 35 for the plaster, 51 for the footings and 28 for the ground slab (each part is rounded up on its own, the total once).

Use your own plan

Draw the house room by room in the floor plan creator, add the floors, stairs and roof, and open Build the house. Choose the wall type (Pakistani or UK brick, German or Dutch brick, concrete blocks), the mixes, the plaster thickness, the footing and slab sizes and the bars; every number follows the plan. Our guide on drawing a floor plan shows how to draw it. For a single wall or slab, the brick calculator, concrete calculator and rebar calculator do the same sums on their own.

Frequently asked questions

How many bricks are in 1 m² of 9-inch wall?

About 108 Pakistani bricks with ⅜ in joints (54 per leaf, two leaves), plus 5 % for breakage. A 4½-inch wall takes half that.

Why are my wall numbers higher than the room sizes suggest?

Outside walls are measured along their middle line, which is longer than the inside of the rooms, and the triangles at the ends of a gable roof are brickwork too.

Are columns and beams included?

No. A framed house or a house in an earthquake area needs columns, beams and bands that an engineer designs; add their concrete and steel to these quantities.

How much steel does a slab need?

With 10 mm bars every 150 mm both ways, about 9 kg per m² including 10 % for laps. Your engineer may ask for more, or for two layers.

Is sand measured loose?

Yes. Sand and stone are loose volumes as delivered, and cement is counted in whole bags.