Building blocks or building bricks?

Walls What is the best construction material to use for a wall? K R Srikanta Prasad explores the pros and cons of using bricks and concrete blocks.

Having just a roof over our heads without walls can be impractical. In any liveable space, walls form a major component. We build our homes “brick by brick” and every brick that goes into making the wall matters. In this modular age, trend changes occur for practical reasons. The old building mantra has now changed to “block by block” or “panel by panel”! While the material changes, the wall remains!

During the “cave era”, man lived within strong rock walls and roofs which were natural and safe. Slowly he moved on to homes built with mud walls that were more flexible and convenient. Later came sundried bricks and stones. Every new change has been geared towards shapes that were more well defined and handier for construction. Clay bricks have prevailed from the time of the Harappan civilisation. The bricks have been made in different sizes to suit the times and local conditions. Then the burnt brick sizes were standardised and have remained in the market for hundreds of years.

These standard table moulded bricks are widely used even today. They have many benefits. They are an age-old and highly durable material, they are easy to handle, workable, adaptable and practical. Bricks can be purchased in different grades and are generally affordable. As they are made of clay, thermal insulation is an important quality which makes for the creation of comfortable places. The standard bricks can easily be cut into a fraction of their size which makes it easy to complete difficult bits while building a wall.

The same bricks can also be used to create walls of different thicknesses like a load bearing wall or a partition wall. Bricks are quite small in size and can be used in different masonry bonds that are structurally stable; they can also be used to build arches. High-end wire-cut bricks can also be left exposed without being plastered or painted to give the wall an aesthetic look.

In the current construction scenario, the ever beautiful bricks have their negatives too. They account for a higher labour cost both, during manufacture and construction, which is why their prices seem to be rising. The slow rate of construction makes them unsuitable for large time bound projects. Walls are thicker and hence carpet area is less. An increased structural cost is incurred on account of more self weight. They need to be soaked in water before construction which adds to time and cost.

Now, due to growing demand and changing trends, there are many large scale constructions which are framed structures. Even small dwellings are built with RCC pillars and beams for flexibility as well as more built-up area. Under such circumstances, even the elements of the walls have been changing from bricks to concrete blocks.

As the demand for wall elements grow, there are a variety of blocks that are available depending on budget and purpose. It ranges from locally made crude blocks to highly precise factory mace concrete hollow blocks. These blocks also have their benefits. The units are bigger and use less mortar as well as less construction time. If the blocks are hollow, they are lighter making them ideal for high-rise framed structures. Quarry-waste is used for manufacturing, in which sense, they are eco-friendly. Waste material like fly-ash and cinder are used for certain variety of blocks which are very light and available in bigger sizes. Factory-made concrete blocks have better quality control, a good finish and strength. Block walls are thinner compared to brick walls.

Mass production is possible while labour cost remains low. Ideal for modular construction. Good quality blocks can be exposed without plastering. Water usage minimised during construction.

But concrete blocks also have their lows. Bricks provide better thermal insulation than concrete blocks. Factory made high quality blocks are expensive and not as workable as bricks in several situations. Quality is not assured in locally made concrete blocks which are generally used for temporary sheds etc.

But walls need not be limited to bricks and blocks alone. There are several other materials available such as soil stabilised blocks made out of soil, quarry dust and cement. This is an eco-friendly material that is used in custom made homes which looks beautiful when exposed. But this method might be more labour intensive. Stone walls have also become a new trend, they rarely need plastering, are durable and be used in composite masonry along with bricks.

Terracotta hollow blocks are also popular. They are aesthetically appealing and insulating. In high rise structures, precast RCC wall units are also installed to hasten the construction process.

Finally bricks are bricks and blocks are blocks! It is up to a creative designer and the home-owner to effectively use different material to their advantage. The goal is to build walls that breathe and remain for a long while.

(The writer is a civil engineer)