Building materials

What are building materials? 

Building materials are raw materials or, more commonly, manufactured products used in the construction of buildings or civil engineering works.

What are the characteristics and properties of building materials? 

Building materials are used in large quantities, so they must come from abundant, inexpensive raw materials. This is why most construction materials are made from widely available materials such as sand, clay, and stone.

The required manufacturing processes should also consume low energy and not be excessively complicated. This is why glass is considerably more expensive than brick, even though both come from such common, abundant raw materials as sand and clay, respectively.

Building materials come in many varieties, as do their characteristics, but one thing is constant among them: they are durable. Depending on their intended use, they must also meet other requirements, such as hardness, mechanical resistance, fire resistance, or ease of cleaning.

As a general rule, no building material simultaneously meets all the required needs; architecture, engineering, and other disciplines related to construction are responsible for combining materials to meet the demands of each project adequately. 

To use and combine building materials properly, designers must know their properties. Building materials’ characteristics may vary from manufacturer to manufacturer, though they must always meet minimum requirements. The specification sheets for each product, which are prepared by the manufacturers, must be considered throughout projects’ development phase.

The materials’ different properties include the following:

Density: relationship between mass and volume

Hygroscopicity: ability to absorb water

Coefficient of expansion: variation in size depending on temperature

Thermal conductivity: ease with which a material allows heat to flow

Mechanical resistance: ability of materials to withstand forces

Elasticity: ability to recover the original shape when force is removed

Plasticity: the material’s permanent deformation under a load or force

Rigidity: a material’s ability to resist deformation

Regulation on building materials

In European countries, building materials are regulated by a series of codes and regulations that define the characteristics they must meet and their scope of application.

The purpose of this regulation is twofold: on the one hand, it ensures minimum quality levels in construction; on the other, it lets architects and engineers know the behavior and characteristics of the materials used more precisely.

The most widely used international standards to regulate construction materials are ISO standards. In Spain, AENOR is a certifying entity that governs materials.

What are the different types of building materials?

By considering the raw material used for its manufacture, building materials can be classified into various groups:

Stone

Derived from rocks obtained from nature. Rock can be used directly without treatment or as a raw material to create other materials. The types of stone and its derivatives most used in construction include granite, marble, limestone, slate, sandstone, gravel, lime, plaster, cement, mortar, concrete, sand, glass. 

Ceramic

Clay is chemically similar to sand: in addition to silicon dioxide, it contains aluminum oxides and water; however, the size of its particles is much finer, and when wet, it is plastic in consistency. When mixed with dust and other elements from the soil, clay forms mud, a material that is used in various ways. When clay is heated to high temperatures (900°C or higher), it hardens, creating ceramic materials like brick, roofing tiles, stoneware, ceramic tiles, etc.

Metallic

The most used metals are iron and aluminum. The former is alloyed with carbon to make

steel, which is used in structures by itself or with concrete to create reinforced concrete. Other metals used in construction are copper, zinc, and titanium.

Organic

Primarily wood and its derivatives, although other organic plant elements are also used (or have been used in the history of construction), such as straw, bamboo, cork, linen, textile elements, or even animal skins.

Synthetic

Mainly plastics derived from petroleum, though they can also often be synthesized. These are widely used in construction due to their unchanging nature, which also makes them very non-eco-friendly due to the difficulty in recycling them. Tars and other polymers, as well as synthetic products of different kinds, are also used. Synthetic materials are used in a wide range of products, such as binders, sealants, waterproofing agents, and insulators, as well as in the form of paints, enamels, and varnishes.

Fun facts about the evolution of building materials

For centuries, the Great Pyramid of Giza (2560 BC) was the tallest structure in the world. It demonstrates one of the most important contributions to the design of any building: modulation. The stones were cut into sizes that made it possible to transport and place them. Currently, all construction materials are modulated to facilitate assembly and prevent waste.

In ancient Mesopotamia, another material was used: brick, which was used to build the first cities. Applying enamels to the brick is one of the earliest examples of plastic integration. In Mesoamerica, evidence of the pyramids reveals an obsession with representing their symbolic universe in three dimensions, using stone and mud bricks.

In Rome, an impressive breakthrough was made with another material that almost seems miraculous: pozzolana, a powder that turns into stone when mixed with water. This material made it possible to build the Romans’ main buildings and public works, notably the Pantheon (125 AD): its vault still amazes visitors.

In 1851, the first Great Exhibition of the Works of Industry of All Nations (or simply, the Great Exhibition) was held in London. The Crystal Palace was built for the occasion; iron was used for the structure, and glass was used to cover the building. The building was made via the first prefabrication process, material modulation, and assembly in record time.

The Great Exhibitions, later the World Fairs, continued to create impressive structures with new materials for their day; these were intended to be ephemeral works, but in some cases, they lasted over time and became iconic features of their countries. The most famous example is the Eiffel Tower, built for the World’s Fair in 1889.

In Spain, Ferrovial has carried out extraordinary architectural and engineering projects, initially using reinforced concrete. The company has stayed at the cutting edge in terms of materials, techniques, and capacity to respond to infrastructure needs ever since.