Focus on materials #1
This blog post is the first in a new series focussing on building materials. Each post in this series will explore a different material looking briefly at its history, use, appearance, design potential and, an aspect which is becoming increasingly important, its environmental impact. The aim of the series is to introduce and showcase the potential of each material and offer an overview of the advantages and disadvantages of its use in new building projects.
The humble brick
In the UK housing is synonymous with brick. In many cases bricks form the backdrop to our everyday lives, we may live, work and socialise in buildings built of brick and barely notice. This everyday material however, deserves closer attention, not only because of its possibilities for architectural expression but also due to its potentially harmful environmental impacts. As awareness increases of the environmental impact of building materials, architects and clients alike will need to take a second look at the humble brick and make careful decisions about why, how and when to use bricks.
A very brief history
The most basic form of brick, the unfired mud brick dates back to around 10,000 BC. The first fired bricks began to be produced around 3,500 BC, dramatically improving strength and resilience and resulting in a material comparable to stone. In the UK, the nineteenth century industrialisation of the brick production process led to increased availability and reduced cost and the humble brick was propelled to its status as the go-to material for both commercial and residential buildings.1 The UK’s love of brick continues today well into the 21st century with many new residential and commercial buildings being sheathed in a skin of traditional brickwork whilst others take advantage of technical advances to use bricks in more innovative ways.
Reasons to use brick
Due to the proliferation of brick and its longevity as a construction material, one of its key advantages is familiarity. The properties of brick, together with construction methods and detailing are well understood, with architects and builders well versed in how to use brick to best advantage. Another plus point is its durability and low maintenance requirements. Many of the brick houses we live in today date from the 19th century with the inherent qualities of the original brick walls still intact. Brick also offers much potential for architectural expression with a large range of brick and mortar colours, bonding types and design details possible.
Appearance of brick
One of the attractions of brick as a construction material and a key reason why architects often choose it is its diversity of appearance and potential for design creativity. Within the gamut of brick types available are a wide variety of colours, textures and even special size options, for example extra long bricks or rounded bull nose bricks. In addition to the bricks themselves, three other factors have a strong influence on the overall appearance of the brickwork: the bonding (i.e how the bricks fit together), the mortar colour and the pointing (the type of mortar joints used). A quick look at the Brick Development Association’s ‘Brick Bulletin’ https://www.brick.org.uk/bulletin/ illustrates the creativity and architectural expression possible using brickwork across a range of building types.
Environmental impact & mitigation measures
Unfortunately, despite all the positive reasons to choose brick, the key disadvantage of this ubiquitous material is the environmental impact associated with its production, predominantly the use of large amounts of fossil fuel energy to fire the bricks and the associated CO2 emissions. The brick industry is working to reduce its environmental impact and has taken a number of measures in recent years to mitigate some of the worst aspects, such as the transformation of former clay mines into water based wildlife reserves. However, the fundamental fact that large amounts of energy and water are required in the brick production process remains difficult to tackle.2
Several factors should be considered when choosing brick for a building project. Firstly, the benefits of durability and longevity. Despite the high energy use in the production of bricks, the potential for the bricks to remain in place for many years and many future occupants of a building mitigates against the initial energy outlay. Buildings that are designed for long term use with an element of flexibility to facilitate future adaptation are suited to brickwork. Consideration should also be given as to whether reclaimed bricks can be used for any part of the project. Reclaimed bricks have a particular, characterful aesthetic which can add texture and interest to a new building project or may suit an extension or alteration where new brickwork would not be appropriate. Furthermore when bricks are used, the specification of lime mortar rather than cement based mortar would allow the bricks to be easily reclaimed at the end of the building’s life.
The first in this series of ‘focus on materials’ posts has looked at the humble brick. This ever popular building material has many positive aspects including familiarity, variety and longevity. The negative aspects of using brick are however associated with the energy required and resultant emissions produced through the firing process, a factor which is becoming increasingly important in the light of recent climate change predictions. However, the potential for brick buildings to be re-purposed throughout their lifetime and for the bricks to be re-used again in the future mitigates against the initial energy required in production. If bricks are used wisely and with thought for their environmental impact through their lifetime, bricks have the potential to continue to be used in creative ways for many years to come.
- Campbell, J.W.P. Bryce, W (2003) ‘Brick: A World History’ Thames & Hudson: London
- GreenSpec (2019) Bricks: unfired, fired, reclaimed & calcium siicate. Available at: http://www.greenspec.co.uk/building-design/bricks [accessed 21-oct-19]