👋 Hi pals, Josephine here with a quick note about this edition…
This is Real Green Estate’s first newsletter series: a 3-part exploration of the UK’s historic buildings, written by the brilliant Lydia Loopesko.
Lydia is a fellow climate friend and is passionate about the potential of historic buildings to mitigate emissions from the construction sector.
Her first part (this article) explores how our historic buildings have not just withstood the test of time, but can also teach us valuable lessons about adapting to climate change.
Part two and three to follow!Â
Historic buildings make up a significant portion of the UK’s building stock: 20-30% (6.2 million) were built before 1919. Almost five percent of buildings across Great Britain lie within Conservation Areas, and 2% are listed. These buildings are notoriously draughtier and leakier than modern constructions and create a significant challenge for the UK’s efforts to promote energy-efficiency and reach climate targets. Yet if we only consider historic buildings as a climate challenge, we may overlook the opportunity they give to cut emissions and learn from the past on how to adapt to the changing climate of the future.
When people think of historic buildings, they conjure up images of the Tower of London or Westminster Abbey. However, historic buildings can extend the whole gamut of history. Oxford dictionary defines historic as ‘important to history or likely to be so.’ What is likely to be thought of as historic is any existing building that is considered to be unique; the youngest building listed by Historic England dates to 1997. Furthermore, history is not universal; what is considered historic to one region may not be considered so by another. However, for the sake of simplicity, we will only be talking about buildings that fall under heritage protection in the UK (either as listed buildings, scheduled monuments, or within conservation areas). Preserving these buildings comes with extra challenges, but their renovation is usually the most sustainable option.
A building requires energy throughout its lifetime, be it during its construction or its operation. The total carbon footprint of a building is referred to as its embodied carbon and includes all the carbon emitted over a building’s lifetime. For a historic building, the carbon from its construction phase has already been emitted, and depending on its age, may have been negligible. However, these buildings do require more energy to maintain and heat, not to mention the red tape they demand regarding maintenance, and many prospective building owners prefer to build new, rather than take on the challenges of retrofitting older structures. Yet, a look at how these buildings were built to adapt to various climatic conditions and used over time can teach us not only how to better maintain them, but how to become more climate friendly in the future.
This three-part series on importance of historic buildings for greening our building stock is divided into three discussions:
How historic buildings forced us to adapt to changes in climate;
How historic buildings can inspire our adaptation efforts going forward;
How retrofitting buildings is an important step for climate action.
Part 1: A history of adapting our buildings to the climate
Prior to the middle of the 19th century, the main building materials were timber, stone, and brick; stone was largely reserved for high-status buildings or rural structures, whereas most urban vernacular buildings used brick and timber. These materials would have been locally sourced and transported by cart. Cart-transported stone has a negligible carbon footprint and timber is naturally a carbon sink; one tonne of wood removes 1.8 tonnes of CO2, which is then preserved in the building rather than released through decomposition. The main emission source from before the mid-19th century would have been from bricks. Bricks would have been made locally and fired in small wood-burning ovens. It is impossible to calculate actual carbon footprint of pre-industrial bricks, but current emissions from wood fires are 2.5 times higher than those of the gas most-often used to fire modern bricks. Between the bricks, builders largely used carbon-neutral lime mortar, which emits carbon as it is mixed, to then be absorbed back as it sets.
Before widespread use of coal in the Industrial Revolution, homes were heated with wood-burning fireplaces, and a building’s layout was optimised as such. Most vernacular buildings were small, made of only a few rooms, often with a single central fireplace for more efficient heat distribution. The same held true for larger buildings. Take as an example the Elizabethan Hardwick Hall; its centre consists of a long spine of chimneys to distribute heat more efficiently to both sides. The south side has large windows to trap sunlight and enjoy the summer light and heat, whereas the north side contains smaller rooms that are easier to heat and retreat to in the winter.
The rise of high-emitting materials
The middle of the 19th century saw the advent of the Industrial Revolution and the root of all our climate woes. Mechanisation allowed more bricks to be fired faster, and the dawn of trains allowed for their long-distance transport. Emissions-producing Portland cement was invented in 1824 and gradually replaced lime mortar; it is still the predominant cement used in construction to this day and produces about 1 tonne of CO2 per tonne of cement. Steel became more popular and led to the invention of reinforced concrete in 1867, which, after steel, is among the highest-emitting materials (see below).
With industrialisation came considerable population growth in the UK and the spread of terraced housing across the country. In the Georgian era (1714-1830), terraced houses had largely been used for wealthy homes, yet they were quickly seen as an efficient way of housing the expanding population. Despite the advent of steel and concrete, these materials remained largely for use in industrial buildings and the ubiquitous Victorian (1830 – 1901) terrace still used traditional brick or stone. Brick terraced houses continued to be popular well into the next  century, but it was only in the early decades of the 20th century that the use of insulating cavity walls became widespread. Instead, Victorian terraced houses were built to create microclimates; the rooms were small and easy to heat, each with its own fireplace, whereas the hallways were colder. The single external wall was naturally breathable, making the house draughtier, yet the typical Victorian terraced house was also usually surrounded on both sides by other houses, meaning it lost less heat (unless semi-detached). Terraced houses were also easier to cool with the invention of the sash window, which provided much more ventilation than the casement window before it. When well-balanced, the sash window could be opened at the top and bottom providing a natural flow of air.
Before the 20th-century, and despite advances in building technology during the Industrial Revolution, buildings across the UK retained similar layouts: small rooms that were easy to heat with draughty corridors creating a variety of microclimates for the user. These buildings changed the user’s behaviour to fit the climate, rather than changing a building’s climate to fit the user. Research suggests that buildings with a variety of temperature zones, can help us adjust to find a wider range of temperatures comfortable. Yet this natural temperature variation disappeared in subsequent architectural styles. As housing demand increased alongside access to cheap and reliable energy in 20th century, a building’s layout became independent from its environment. As we will see in Part 2, modern buildings, though much more airtight, present their own challenges in the face of climate change.
Stay tuned!