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How to reduce embodied carbon in the construction sector

Embodied Carbon is the carbon dioxide (CO₂) emissions created from materials and the construction processes used when constructing buildings. To obtain the true calculations and start to look at how to reduce embodied carbon in the construction industry, we need to look at the whole process to make a completed building. These calculations should consider the components/material required to make the building, the machinery needed for assembly, transportation used to get it to the site and how the land is prepared or the demolition of the structure.

What is embodied carbon?

In simple terms, embodied carbon is the footprint of assembling a building; not to be confused with the ‘operational carbon’ affect – the amount of carbon emitted once a building is in use.
With climate change and sustainability a key focus, companies are starting to look at ways to reduce their carbon footprint and how they impact the environment. One area of particular interest for the Glanville team (and our clients) is how we can reduce embodied carbon in the construction industry.

Why embodied carbon is an issue

Architecture 2030 has reported that the world’s building stock is expected to double by 2060, however, our building practices can’t stay the same if we’re also to achieve the ambitious goals of halving carbon emissions by 2030 and reaching Net-Zero by 2050.

Historically, most buildings have been made with a high amount of concrete, it’s the most common form of a structure comprising a network of columns and connecting beams that form the structural ‘skeleton’ of a building. However, where concrete is used most is within the foundations and substructure. Concrete is a very versatile building material that can be used for the foundations, beams, floors, roofs, walls, drains and cladding, however, it’s a high contributor of CO₂ and therefore, an area we can review when establishing methods to reduce embodied carbon in the construction industry

The reason why concrete is such a high contributor to embodied carbon in the construction industry is the way its created. The process of cement production requires a huge amount of energy to heat the core material (which creates CO₂), alongside the chemical reaction produced from the core material when exposed to heat which creates yet more CO₂.

When you factor in the limited options to transport concrete from one location to another, the amount of CO₂ produced is considered unnecessarily high. But it’s not just concrete we should look at, steel needs to be under review too as steel emits on average 1.83 tons of CO₂ per tonne of steel manufactured adding over 3.3million tonnes of CO₂ every year. However, one positive for steel is that it can be reused or recycled.

Glanville has already taken the first steps to help reduce the amount of embodied carbon in the construction industry as a whole. The team are working towards offering calculations of the embodied carbon for new projects to identify “carbon hotspots” and reduce carbon where possible. This could be as simple as reviewing concrete specifications to ensure less cement is required, reducing the depth of foundations, shaving an extra 25mm off a slab depth or reducing the specification of timber from C24 to C16. Although these small changes don’t sound like much, at the cost of a little extra time at the design stage, together they can provide significant savings to the embodied carbon of a building, (and also the cost to the client!)

For existing buildings, when a structure is decommissioned and requires demolition to make way for a new one, the emissions locked into the original building are wasted and the new building’s material manufacturer and construction processes create new emissions. At Glanville, we work with our clients to review where we can re-use parts of existing buildings. The measures outlined in the ‘Built Environment Declares Climate and Biodiversity Emergency’ initiative include “upgrade existing buildings for extended use, a more carbon-efficient alternative to demolition and new-build whenever there is a viable choice” following a review of ways we can look to reduce embodied carbon in the construction industry.

Another viable option for some existing structures is to retrofit and ‘build up’ adding additional floors to existing buildings. Doing this means no additional land is disturbed, materials can be kept to a minimum and demolition of existing buildings is made redundant.

In the past, clients have wanted to work with us to re-use existing buildings due to the advantages of cost, programme and heritage, however, now the demand for reduced carbon is pushing even more towards re-use, re-purposing and retrofitting. Clients, their customers and the general public are becoming more aware of the effect of CO₂ on the planet, and are looking for innovative ways we could reduce embodied carbon in the construction industry.

Glanville has considerable experience working with existing buildings, whether it be restoring and converting a heritage factory building such as the iconic Horlicks factory above in Slough into luxury flats, adding additional storeys to 1970s apartment blocks or converting existing industrial warehouses for residential use. We are think creatively and advise at an early stage whether the retention of an existing building is feasible, and make imaginative suggestions as to how it can be incorporated into a new scheme.