The choice of building materials to use in a construction is determined by factors such as availability, cost, tenacity and durability.
Below are some of the most common building materials in Kenya.
This is the most common construction material in the country. There are two types of stones in the market; manually cut stones and machine cut stones. The manually cut stones are strong and are preferred for foundations and load bearing walls.
Machine cut stones are well shaped with an even surface, which helps in saving on time and labour cost that would have gone into dressing. They also save on mortar during building and plastering since there are no uneven gaps to be filled.
This is used with cement, and sometimes lime, to make mortar for masonry work and plaster. The material is also used as a part of the concrete mix.
These are made using clay which is compressed to form blocks then air-dried. After drying, the bricks are burnt or fired in a kiln to permanently harden them.
Fired bricks are commonly used for construction of walls and arches as a substitute to stone.
Bricks can have hollow cavities to lighten them and hasten the drying process. The products are popular due to their fire resistance abilities
Metal features prominently in structural framework of buildings. While there is a wide variety of metals that can be used in construction, steel remains the most popular in the industrialised world.
Steel is an alloy of iron combined with a small percentage of carbon. It is strong, flexible and long lasting making it the most preferred metal for structural building. It is commonly used to make reinforced concrete used as support for structures in buildings, dams and bridges.
Besides steel, metals such as aluminum and copper have continued to gain popularity as a result of their rust and corrosion resistance.
Copper is commonly used for electric wires, indoor design elements and piping for water supply.
Aluminum is used for gutters, roofing sheets and roofing nails while other metals such a gold silver and chrome are used for decorations due to their high cost and lack of tensile strength and hardness.
Cement features commonly in the world’s most popular construction materials list. It is easily the most essential building material with about 6 billion tonnes being manufactured every year. Cement is used in masonry work as an adhesive to hold the stones, bricks and blocks in place as well as in plastering.
The material is mixed with aggregate (sand and gravel) as a binder to form concrete which is commonly used for building of floors, bridges, dams and roads in the country.
This is a composite building substance made by combining cement, gravel, sand and water in recommended proportions.
Cement, which acts as the binder, chemically reacts with water through a process known as hydration – binding the other components into a stone-like substance.
Concrete is strong, very durable and the most used man-made building material globally. It has a high compressive strength but low tensile strength and must therefore be reinforced using steel bars or rods.
This is one of the oldest building materials in the world – mainly used in panelling, flooring and general finishing. It is also used in construction of roofs, ceiling, doors and window frames and exterior cladding.
In recent years, the use of wood as a building material has reduced with many people opting for its alternatives. This is mainly due to the rising cost of the material amid growing threat of deforestation.
Glass is quickly becoming an essential material in modern architecture. The material is important on buildings since it provides the ability to let in light into the interiors while simultaneously locking out undesirable weather elements.
The provision of natural lighting is crucial in saving on energy costs.
Though glass is very brittle, modern technologies have enabled it to be used for covering entire walls of a building with the support of some form of frame. The use of decorative glass is now a trend as more designers seek innovative ways to decorate the exteriors of buildings.
This is among the world’s fastest growing plants. It has a high strength-to-weight ratio which is useful for structures. It also beats concrete, brick and wood in terms of compressive strength and rivals steel in tensile strength.
Bamboo is mostly used in building houses, bridges and scaffolding. It can also be cut and laminated to produce sheets and planks commonly used in flooring, furniture and cabinetry.
The use of prefabricated building materials (prefabs) is fast gaining currency in the country. The technology involves the frames of houses being manufactured in a factory before being shipped to a construction site for assembly.
There are different types of prefabs available in the market with the most popular ones in the country being the pre-engineered steel structures. Prefab structures are easier, cheaper and faster to construct than the normal brick and mortar buildings.
Glazed ceramic tiles
These have quickly become one of the most popular building materials in modern buildings. They are formed from a mixture of clay, sand and natural additives moulded into desired shape then permanently hardened by heat in a kiln at very high temperatures of up to 1500 degrees.
They are commonly used to cover floors, walls and surfaces such as counter tops.
The tiles come in a wide variety of designs ranging from simple squares to complex mosaics. They are durable, resistant to tread wear, have colour permanence and are easy to clean.
These are the most common roofing materials in the country due to their affordability. They come in a variety of colours, shapes and sizes and are usually produced with a series of alternating grooves and ridges (corrugation) which increase their bending strength.
Additional improvements such as galvanisation (coating with zinc to prevent rust and corrosion) have added to their popularity among home builders. The sheets are strong, corrosion resistant, light in weight and easy to transport.
Their light weight property reduces stress exerted on the underlying walls hence they do not require much structural support.
These are thin flat slabs of fired clay, concrete, cement or metal usually laid in rows to form a roofing cover. The most common in the country are clay tiles, popular in urban areas.
Due to their heavy weight, roofing tiles require more wood for the roofing truss compared to roofing sheets. They are very durable and are the best for harvesting rain water since clay is a natural filter.
However, roofing tiles can leak if not provided with an underlay of polyvinyl paper sheets or light gauge roofing sheets.
Concrete tiles are a great alternative to clay tiles due to their many similarities the only difference being that they are lighter in weight and are available in a vast array of colours.
Stone coated roofing tiles, a combination of natural stone and zinc-alume coated steel are also gaining popularity due to their durability, easy installation and maintenance, attractive appearance and light weight which reduces timber requirements for the truss.
However, they are more pricey compared to other roofings and are not suitable for rain water harvesting.