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  6. Calculating the number of bricks
Calculating quantities

Calculating the number of bricks

The number of bricks depends on the used format.

By means of a table

Here we give a table with the number of bricks and amount of mortar per m² measured for a half brick wall (1 stone wall = x2) in half stone bond, this is masonry that exclusively consists of stretchers, and with a joint width of 10 mm. Included is a chopping/breaking loss of brick of 3% and a prefab-mortar loss of 3%. With a traditional mortar you can count on 10% of mortar loss. (Data from Royal Assembly of Dutch Brick Factories and from Jozef Dockx)












Table of currently used Dutch/Belgian brick types and formats

By means of surface calculation

  • Put the bricks on their side on one square meter (100 x 100 cm) and count how many stones can be placed horizontally and vertically.
  • Multiply both numbers by each other and you get the number of stones necessary for 1 m²;
  • Take into account a cut and break loss of brick of 3 % and you get the number of bricks per m² for a halfstone wall (approx. 10 cm thick);
  • Double the number of bricks and you will get the number of bricks per m² for a wall of one brick thick (approx. 20 cm);
  • Measure the necessary surface by multiplying the length by the height.
  • Do this for every façade.
  • Next you have to multiply the sum of the surfaces with the number of bricks per m² and you will get the number of bricks necessary.

Example for a "module 50" (see Moduul 50 in table above):

  • There can be 5 bricks next to each other (5 x 20 cm = 100 cm) and 16,5 bricks on top of each other (16,5 x 6 = 99 cm) in 1 m².
  • 5 x 16,5 = 82,5 bricks/m².
  • 82,5 + 3 % = 85 bricks for half stone wall (approx. 10 cm thick)
  • 85 x 2 = 170 bricks for wall of 1 stone (approx. 20 cm) thick.
  • Surface façade (1 brick thick): l x h = 1,59 x 1,25 = 1,988 m²
  • Surface gabled façade (1 brick thick):
  • ((l x h) / 2) = ((1,59 x 0,78) / 2) = 0,62 m²
  • Surface sides 1 brick thick:
  • (l x h) x 2 = 1,59 x 0,59 x 2 = 1,876 m²
  • Surface sides ½ stone thick (l x h) x 2 = 1,59 x 0,54 x 2 = 1,717 m²
  • surface rear side 1 brick thick: l x h = 1,59 x 0,59 = 0,938 m²
  • surface rear side ½ brick thick: l x h = 1,59 x 0,54 = 0,859 m²
  • Total surface ½ brick thick x number of bricks per m² = (1,717 + 0,859) x 85 = approx. 220 bricks
  • Total surface 1 brick thick x number of bricks per m² = (1,988 + 0,62 + 1,876 + 0,938) x 170 = approx. 920 bricks
  • Total number of needed bricks = 220 + 920 = 1140 bricks

By means of volume calculation

In order to get a wall in cross bond, divide the volume of the wall (expressed in cm³) (h x w x d) by the volume of the brick including joint. Add to this a cut and break loss of brick of 3 % and you will get the number of bricks necessary per m².

Example for 1 m²:

  • volume of wall = h x w x d = 100 x 100 x 20 = 200000 cm³
  • volume of brick module 50 including joint of 1 cm = l x w x d = 20 x 10 x 6 = 1200 cm³
  • 200000 / 1200 = 166 bricks
  • 166 + 3 % = approx. 170 bricks

Calculating the number of fire bricks for the oven floor

The principle of the calculation of number of bricks is applied to the oven floor.

Example (by means of building plan):

  • length oven floor = l = 1m
  • width oven floor = w = 0,75 m
  • l x w= 1 x 0,75 = 0,75 m²

Place the bricks on their flat side on one square meter (100 x 100 cm) and count how many bricks can be placed horizontally and vertically: 5 bricks next to each other (5 x 19,3 cm = 96,5 cm) and 11 bricks on top of each other (11 x 9,3 = 102,3 cm).

  • 5 x 11 = 55 bricks/m².
  • 55 + 3 % = 57 bricks on their flat side (approx. 5 cm thick) per m²
  • 0,75 m² x 57 bricks/m² = approx. 43 bricks
Calculating the number of fire bricks for the oven vault

By dividing the surface of the vault by the surface of the used brick you can estimate the number of fire bricks. ( or to be multiplied with the number of bricks/m² 1 brick wall)

  • You can calculate the surface of the vault (+ oven flloor) by means of the surface of a rectangular parallelepiped by adding up the surfaces of the 6 sides (A = 2(ab + ac + bc));
  • Subtract the surface of the oven floor and you will get the surface of the vault;
  • multiply the surface of the vault with the number of bricks/m² stone wall.

Example (by means of building plan)

  • a = 0,8 m (width vault)
  • b = 1 m (length vault)
  • c = 0,4 m (height vault)
  • number of bricks /m² in head joint module 50 = (11 x 20) = approx. 220
  • surface of used bricks= 0,09 x 0,05= 0,005m²
  • surface vault + oven floor (A) = 2 (ab + ac + bc) = 2 (0,8 + 0,32 + 0,4) = 3,04 m²
  • surface oven floor= a x b = 0,8 x 1 = 0,8 m²
  • surface vault = 3,04 - 0,8 = 2,24 m²
  • number of bricks= (surface vault x number of bricks) / (m² stone wall) = 2,24 x 220= 493 bricks
Or
  • number of bricks = surface vault / surface used bricks= 2,24/ 0,005= 448 bricks
  • + 3% cut and break loss of bricks = 448 + 13,4 = 462 bricks