History and interesting facts about clay bricks

with thanks and recognition to Dr. D van Graan. 

The use of unbaked clay bricks for houses can be dated back to about 7500 BC

Fired clay bricks can in actual fact be called synthetic rock as it has basically the same properties as Basement (primitive) Rock. The reason being that the clay bricks are made from clay and when fired at 1000° C it basically turns back into Basement Rock and to change back to clay will again take a couple of million years.

Primitive people for thousands of years built their shelters with anything they could lay their hands on to try and protect them from the elements, like stone, rock, branches, palm tree leaves, mud, and clay, etc.

The Sumerians were the most advanced group of people in the ancient world and lived in Mesopotamia, a land between the Euphrates and Tigris rivers, surrounded by dessert. They were intelligent and educated in that they were the pioneers in civilizing the world, by, for example, being the first to count in tens and also in the sixties and also the “inventors” of the hour into 60 minutes and seconds as well as dividing a circle into 360 deg.

Living in a huge desert-like most people of that time there was a very little rock and stone available and houses were made from mud and clay from the river banks. Every time the rivers came down annually and filled the flood plains, the houses’ walls would “melt”. About 2600 BC they improved on this problem by firing the clay, and the clay brick, as we know it today, 4600 years later, is still made the same. Can you imagine what an incredible evolution it must have been for that era where everything had to be done repeatedly every day, like hunting for food, make a shelter, etc. All of a sudden, the shelter problem gets solved by not having to rebuild your house yearly, but only once, and then it is forever!

In Europe, most people still built their houses with wood as there always were ample trees and timber available, until 1666, when the city of London burnt down completely, because of the narrow streets and the dry wood the houses were built from. After this disaster, London was rebuilt, but only stone and rock were allowed. Because of the slow supply of stone and rock, fired clay bricks were introduced. This was also the start of the town fathers making an extra income for the city by charging the people a levy on each brick they built with, much like the levy we pay on electricity today. This encouraged the people to make larger bricks, to pay less levy, but it became so big that the builders could not handle it and therefore bricks were brought back to size as they are still today.

Standard clay brick size – length 222mm width 106mm height 73mm

Why? – so than an average man can easily pick it up and handle it with one hand and that is also why the Asian brick is smaller to fit their smaller hands

Built-in with mortar – 235 x 106 x 85mm. Brick length is 2 x width and 3 x thickness

Why? – so that you can build in a bond to ensure wall strength

Bricks were also the creator of the following:

  • The first item to ever be made in a mold and not just shaped by hand
  • By being made like this, also the beginning of standardizing articles to be the same in size, color, weight, etc. and mass production as well as production lines.
  • Also, the first in numbering products as well as trademarking. Brickmakers were the first to mark each individual brick with their mark or name before it was baked. This started when the Israelites were slaves in Egypt and each individual was forced to make a certain amount of bricks every day. The only way to ensure this was to count each slave’s daily production and they only counted bricks with names or marks on.

Classification of bricks:

  • NFP (Non-Face Plaster) Commonly known as “stocks” or “mamparras”. Suitable for general building work which is then plastered and painted. Compressive strength should not be less than 7Mpa.
  • NFX (Non-Face Extra) Commonly known as “Clinkers) Used in general building work for extra durability in such areas as below ground level, retaining walls, in-between concrete columns, etc. Compressive strength should not be less than 14Mpa.
  • (E) Engineering bricks. For special structures or loadbearing purposes, also water-bearing structures like manholes. Compressive strength should be in the region of 21Mpa.
  • FBA (Face Bricks Aesthetic) units that are selected or produced for their durability and aesthetic effect deriving from non-uniformity of shape, size, and color – normally up to 7% allowed. Basically, the “lowest” range of Face Bricks.
  • FBS (Face Bricks Standard) units that are selected or produced for their durability and uniformity of shape, size, and color – normally up to 5% difference allowed. FBS Bricks are the “middle” range of Face Brick
  • FBX (Face Bricks Extra) units that are selected or produced for their durability and a high degree of uniformity of shape, size, and color – normally up to only 2% difference allowed. This being the top of the range of Face Brick

The number one rule when building with any Face brick is to MIX!! To avoid color banding, it is a must that Face bricks are taken from different packs and carefully blended during the building operation.

Mortar mixes

Mortar mixes with sand and cement must always be in volume and not weight, therefore a 4: 1 mix will consist of 4 wheelbarrows of sand mixed with 1 wheelbarrow of cement in volume, or roughly 3 wheelbarrows of sand and 1 bag of cement. To lay 1000 standard bricks you will need 3 bags of cement to 06 m³ of building sand or the equivalent of 4 bags of cement to 1 ton of sand.

To plaster 100m² 15mm thick you will roughly need 4ton (3m³) plaster sand and 15 bags of cement