There is increased awareness around embodied carbon. This has resulted in some architects and specifiers asking questions about brick building products – and questioning whether there are lower carbon options available. For Ibstock’s products to remain the go to products – and firmly on specification – we know we need to address these questions.
Project objective: Reduce the embodied carbon of our bricks
This project is ongoing – and, at its earliest stages, was designed to answer two questions:
Is it possible to use less raw material to make each brick?
If we can use less raw material, how can we be sure that there is no compromise to the physical performance and aesthetic characteristics of the bricks?
Project overview
This project can be summarised as ‘changing the size, shape and pattern of the holes. That is true for the frogs in soft mud bricks, and the holes (known as ‘voids’ or ‘perforations’) in extruded, wire-cut bricks. This summary, however, vastly underestimates the scale of the technical challenge.
The process
Looking at areas for improvement in embodied carbon began with understanding the constraints, and what couldn’t be changed – for example the technical properties of any brick made with less raw material had to remain the same. The fact of the bricks being kiln-fired couldn’t be changed, and nor could the atmosphere in the kiln be altered. Our next steps were:
First, we looked at areas for improvement by understanding the constraints, and what couldn’t be changed – for example, the kiln-firing process itself.
Next, we considered using different clay – but each clay type produces bricks with different characteristics, and each requires a factory that is set up in a unique way compared to its counterparts.
We then tried using less material – but it was not as simple as ‘make the holes bigger’! A change in void size means major changes to the process, and our factories can’t be expected to run the same as they have previously
Project outcomes
We have reduced the embodied carbon of the clay in each brick – in some cases by up to 8% (the exact reduction varies by factory).
Using less clay extends the life of the quarry from which our clay is sourced. This is good for the environment, the communities around us - and our business asset resilience.
Less clay and a different void pattern mean less water is used and there is less overall mass to dry. Less energy is therefore used in the drying stage.
Less natural gas is required to heat the kiln – because there is less mass to fire, and the bigger voids create more airflow through each brick.
With less mass, bricks can be run through the kiln more quickly and efficiently – which delivers additional operational efficiencies such as reduced time and cost of changing wear parts.
Quality tests show that there will be no aesthetic change in the useable faces of the bricks – this means architects and housebuilders can still achieve the finish they are looking for.
Lessons learnt & next steps
Hard work pays off. At the time of publication, some of Ibstock’s factories have increased their brick voids to lower the embodied carbon of its bricks with several currently undertaking trials.
Set realistic expectations. We now know that the diversity of raw materials and product ranges means we cannot achieve the same uplift with the voids at every factory.
Be realistic - but stay ambitious. Our aim is now to achieve the best embodied carbon improvement possible at each site. That is likely to mean bricks with voids of 30 to 40% of the brick volume, and an average reduction in embodied carbon of 8% at some factories – with ambitions to go further as Ibstock learns more.
Progress is rewarding, but, slower than planned. We promised this paper would be honest, and it is. This project is certainly delivering encouraging outcomes – but it was longer and more complex than we imagined or planned for.
Looking beyond voids. Changes to the traditional brick can make a big difference but we can’t stop there – thinner bricks, brick slips and alternative systems are all in our pipeline of new and more sustainable products.
Our intention is to achieve even more ambitious goals as we implement the lessons learnt in the initial phase of this project.
Other useful benefits
The reduced mass means each brick is lighter – this results in efficiencies in transport & handling:
Forklifts can move more bricks at once.
Lorries restricted to a certain tonnage can carry more bricks in a load and therefore reduce transport miles overall.
Bricks are easier to lay – which speeds up the construction.