Timber vs Concrete and Brick: How Material Choices Shape Sustainable Construction

Understanding Embodied Carbon in Construction

Buildings contribute almost 40% of global greenhouse-gas emissions; about 11% of that figure comes from the embodied carbon in construction materials rather than the energy used when a building is occupied. In the UK built environment, embodied carbon in the materials used for construction and refurbishment accounts for roughly 20% of emissions. Materials such as concrete, steel and fired-clay bricks require large amounts of energy for extraction and manufacturing, producing significant carbon dioxide emissions. By contrast, using reclaimed or renewable materials can dramatically reduce a project’s carbon footprint without sacrificing performance.

Why Traditional Concrete and Fired-Clay Bricks Are Carbon-Intensive

Energy-intensive cement production: Concrete is made up of cement, aggregates and water. While aggregates and water have relatively low impacts, cement production has the highest embodied energy. Limestone and other raw materials are heated to around 2,700°F in rotary kilns, a process powered largely by coal and petroleum coke. The Portland cement industry is among the most energy-intensive manufacturing sectors.

High emissions from clay bricks: Fired-clay bricks are durable and relatively inexpensive, but their production is carbon-intensive. Globally, consumption of fired-clay bricks is about 2.18 gigatonnes per year, resulting in roughly 500 million tonnes of CO₂-equivalent emissions—around 1% of global greenhouse-gas emissions. Producing bricks requires quarrying clay, drying and firing it in energy-hungry kilns. These activities emit greenhouse gases, cause land degradation, and contribute to particulate pollution.

Transport impacts: New bricks and cement are heavy and often transported long distances. Their weight increases fuel use and emissions during transport. By contrast, locally sourced reclaimed bricks avoid most transportation and manufacturing impacts.

Low-Carbon Alternatives: Mass Timber and Reclaimed Bricks

Mass Timber (Engineered Wood)

Mass timber refers to engineered wood products such as cross-laminated timber (CLT) and glue-laminated beams. These are manufactured by bonding layers of timber to form structural panels or beams with strength comparable to concrete or steel.

• Lower embodied emissions: Wood products require less energy to produce and result in far fewer carbon emissions than concrete or steel. Mass timber buildings can reduce embodied carbon by 30–50% compared with concrete or steel structures.

• Carbon sequestration: Wood acts as a carbon sink. Each cubic metre of cross-laminated timber stores about one tonne of CO₂, which remains locked in the building for decades.

• Lightweight construction: Mass timber structures weigh around 35% less than steel equivalents. Lighter structures need smaller foundations, further reducing embodied emissions.

• Faster, efficient installation: Prefabricated timber panels allow quicker assembly. Projects can be built about 25% faster and at lower cost, reducing site emissions and labour needs.

• Health and comfort: Timber construction supports occupant wellbeing by regulating humidity and providing a warm aesthetic. Many producers fuel operations with residues, making timber manufacturing relatively energy-self-sufficient.

Reclaimed Bricks

Reusing bricks salvaged from demolished structures is a simple but impactful step:

• No new extraction or firing: Reclaimed bricks avoid the quarrying, drying and high-temperature firing needed for new clay bricks, removing associated emissions entirely.

• Local sourcing: Salvaged bricks can often be sourced locally, cutting down on transport emissions.

• Embodied carbon savings: Reclaimed bricks are classed as low-embodied-carbon materials. They support a circular economy by keeping materials in use.

• Character and heritage: Salvaged bricks offer unique colours and textures, adding aesthetic and historical value to new projects.

Evolving Concrete: Low-Carbon Mixes

Concrete remains essential for foundations and some structural elements, but low-carbon options are becoming available:

• Supplementary Cementitious Materials (SCMs): Replacing a portion of Portland cement with fly ash, slag, or natural pozzolan reduces the carbon footprint and improves durability. Some new blended cements cut embodied emissions by up to 25% without performance loss.

• Carbonation: Concrete naturally absorbs CO₂ during its life. Reusing end-of-life concrete and maximising surface exposure can enhance this benefit.

• Optimised mix design: Using less cement while maintaining strength reduces waste and resource demand.

Practical Tips for Small Construction Firms

• Choose timber where performance allows: Use engineered timber for framing, floors, or roof systems. Always seek certified products from responsibly managed forests.

• Specify low-carbon concrete: Ask suppliers for mixes containing SCMs or low-embodied-carbon certifications. Request environmental product declarations to compare options.

• Source reclaimed masonry: For walls, landscaping, or architectural features, reclaimed bricks reduce emissions while adding character.

• Plan for disassembly and reuse: Use modular assemblies and mechanical fixings to make future reuse easier. Mass timber components in particular can be repurposed effectively.

• Engage with sustainability networks: Forums such as REFEA help firms share knowledge, access resources, and stay up to date with sustainable technologies.

Small Choices, Big Impact

The choice of building materials has a profound influence on a project’s environmental footprint. Traditional materials like concrete, steel and new clay bricks carry heavy carbon burdens due to energy-intensive manufacturing and long supply chains. Switching to mass timber, specifying low-carbon concrete mixes and choosing reclaimed bricks can substantially reduce embodied carbon without compromising quality or performance.

A mass-timber structure can lower global-warming potential by 30–50% compared with conventional construction, while reclaimed bricks remove emissions linked to extraction and firing. Even refining concrete mixes with supplementary materials can cut emissions by around a quarter.

For small construction firms, these changes are achievable and increasingly expected in a market focused on sustainability. By making conscious material choices today, builders can contribute to a lower-carbon future and lead the way in sustainable design.