A host of innovations are being introduced into the house building industry as it realigns itself to become more environmentally friendly.
According to the Construction Industry Council, the built environment and construction sector account for 38% of global carbon emissions. Central government is committed to becoming a net zero economy by 2050, making sustainable house building crucial.
While the production of clay bricks, steel, and concrete has historically created high levels of carbon emissions, the industry is now developing low-carbon alternative materials to use in the design, construction, operation, and maintenance of buildings.
Our homes are also responsible for high levels of energy use and carbon dioxide and greenhouse gas emissions; the new approach to construction is not only reducing carbon footprints but also creating homes that are energy efficient and better equipped to withstand the challenges of the future.
Let’s look at the new technology, new construction techniques, and new materials being adopted by the house building sector.
With technology evolving at a rapid pace, innovative techniques are emerging to improve the sustainability of housing development in terms of how homes are built and operated. The technology includes solar panels, rainwater harvesting systems, passive heating and cooling systems, ground and air source heat pumps, and renewable energy from wind, alongside digitisation and automation.
3D printing technology is now widely used; it reduces waste and speeds up construction times. Building Information Modelling (BIM) is digital technology that can enable all professionals to collaborate easily on a project to make the best use of resources, helping reduce waste, lower costs and increase construction speed. Advances are being made into solar skin technology, which creates a thin, malleable layer of photovoltaic cells that can be applied to rooftops or a range of other objects, rather than thick, rigid solar panels: the skin is more visually appealing and energy efficient.
New construction techniques
Prefabricated and modular off-site construction is being backed by central government as a way of boosting housebuilding times. Some local authorities also look favourably on modular schemes in terms of granting planning permission. The approach involves manufacturing components off-site and then assembling them on-site, resulting in reduced carbon emissions and less waste. A factory-controlled environment can improve quality control and enables increased use of renewable and recyclable materials, reducing the embodied energy in building materials, and reducing energy consumption on the finished build.
`Whole life carbon’
A statement from the Royal Institute of British Architects (RIBA) stressed the importance of considering materials and carbon in new homes:
Selection and use of materials are incredibly important in minimising the environmental impact of new buildings. Every material has an ‘embodied carbon’ footprint – usually the less processed the material the smaller the footprint. When designing and constructing a building, it is vital that we consider how each material can perform its required function while using the least embodied carbon possible.
RIBA promotes a performance-based approach to the use of materials, and architects have the skills and knowledge to design and choose the right materials to help buildings on the trajectory towards net zero. It is important to consider the ‘whole life carbon’ that housing will produce over its lifetime. This includes the embodied carbon from the materials used, but also the carbon emitted from the construction process itself, a building’s operations and maintenance, refurbishment, and end-of-life and disposal.
Whole-life carbon balances the impacts between increase in the footprint of materials (e.g., more insulation) with reduction in operational footprint. Good design is essential to producing housing that is as energy efficient to operate and inhabit as possible, minimising the emissions produced from heating, cooling, and lighting, whilst also providing comfortable and attractive homes. Architects can play a key role in designing buildings to be as sustainable, safe, and healthy as possible.
However, in the UK, we are currently lacking consistent regulatory requirements that require the assessment of whole-life carbon across the built environment. It is therefore vital that the Government introduces regulation that includes reporting targets for measuring and reporting on embodied and whole-life carbon. Industry is ahead of the curve with initiatives such as the Built Environment Carbon Database, the RIBA 2030 Climate Challenge and the UK Net Zero Carbon Building Standard.
Lessons from the past
Decarbonising the construction industry is essential to allow the UK to reach the national emission reduction targets of 68% by 2030 and 78% by 2035, according to Professor of Intelligent Engineering Systems within the product design team at Nottingham Trent University, Amin Al-Habaibeh, who noted that materials are still being used that have a high carbon footprint due to the energy used during their production and over their life cycle.
Different approaches to enhance sustainability in buildings are being explored at Nottingham Trent University’s School of Architecture Design and the Built Environment. Research includes work with sustainable materials such as Mycelium structures from mushroom roots that could potentially be used as a thermal insulator in new homes.
Professor Al-Habaibeh said that history can provide lessons and direction for the way forward to reduce the construction industry’s carbon footprint.
The cement and building bricks used in the construction industries are made normally in high temperature kilns, hence consuming a significant amount of energy, the majority is from fossil fuel in many parts of the world. There are many lessons we can take from the past towards a sustainable future, starting with mud bricks buildings that were built about 4000 years ago.
The pyramids of El Lahun and Hawara in Fayoum south of Cairo are great examples of how sun-dried mud and straw bricks can be used to build stable builds that can survive for thousands of years. The same technology was used over centuries to build houses in the same area. The material was put in a mould to manufacture bricks that keep buildings warm in winter and cool in summer due to the material thermal capacity and moisture regulation characteristics.
Similar mud brick technology was used over centuries in Yemen to build what could be described as the first skyscraper cities. In the UK, traditional cob or earth house are well known and there have been attempts to build modern houses using that material. And cob or earth bricks or blocks are now commercially available. They are typically made of clayey soil, straw and water and dried at ambient temperatures.
Significant research is being done now to enhance traditional material properties and strength. For many years, researchers have been investigating new sustainable materials that could provide suitable building properties but can be produced with low carbon footprint, such as using clay and hemp fibres. Hemp-lime material is now commercially available for use in buildings as a low embodied carbon construction material which is characterised by being a good thermal insulator and temperature and moisture regulator. However, more research is also focused now on using waste plastic as a building material due to its durability and availability, creating another sustainable approach to tackle climate change.
A range of green building alternatives have been developed that are both durable and environmentally friendly. They include:
Cross laminated timber (CLT)
This is a sustainable wood product that offers high strength and durability. It’s made by layering wood boards at right angles and bonding them with non-toxic adhesives. CLT reduces reliance on concrete and steel, as it can be used for walls, floors and roofs, sequestering carbon in the process.
Reusing existing materials lowers steel’s carbon footprint and preserves natural resources. Steel is the world’s most recycled material, and it plays a key role in the transition to a low-carbon, circular economy.
Insulating Concrete Forms (ICFs)
ICFs are made from recycled materials like polystyrene or polyurethane foam and are used in the construction of reinforced concrete walls. They reduce energy consumption, minimise heating and cooling costs and enhance the overall energy efficiency of buildings. They are often used in place of plywood or planks for pouring concrete walls: the H-shaped structure allows concrete to be cased between insulating layers, allowing open air and easy access for first fix works. They are strong, improve air quality, offer good sound insulation and are a cost-effective material.
Sustainable building materials
Several sustainable brick alternatives are also available, according to Architecture and Design:
These are made from raw material from the hemp plant, which absorbs high levels of carbon in its lifespan. Hemp is sustainable as it can grow in most soils and climates, reducing transport costs and emissions. Hemp blocks are non-load bearing, glued products, used for partition walls and building envelopes. They can regulate temperature and humidity and offer good acoustic insulation and fire resistance. The low-energy manufacturing process gives it a low-carbon footprint.
Gent waste brick
These bricks are cured not fired and contain 63% recycled waste. Lime captures CO2 from the atmosphere in the process, sequestering carbon over the life of the building. Strong and resilient, a brick contains a third of the embodied carbon of a clay brick over a 60-year lifespan.
Made from waste products, these lightweight and durable blocks don’t need mortar in the construction process. Experiments into creating them using waste cooking oil and industrial waste are under way and further development is likely.
Fly ash bricks
Fly ash is an industrial waste produced in thermal power plants. Lighter and stronger than clay brick, fly ash brick has a smooth surface which eliminates the need for external works such as plastering walls, reducing construction costs. They are sustainable as they prevent fly ash waste from going to landfill, and the construction process has a low carbon footprint; it involves compaction, curing and drying and no fossil fuels. The brick also absorbs less heat, it’s highly durable with low permeability, reducing dampness in walls, and offers fire resistance. They can be used in load-bearing and non-load-bearing walls, and their lightness makes them ideal for high-rise housing development.
K-BRIQ contains at least 90% recycled construction waste. Manufactured through a low-carbon production process that doesn’t need high-temperature firing, they can be used in interior and exterior building work. Their carbon footprint is less than 5% of that of a clay brick, and they are strong, with a high thermal mass.
It may have taken some time, but innovation is changing the sector dramatically as it embraces sustainability, new construction methods, and the use of renewable and recyclable materials. And technological advances and cutting-edge techniques promise more improvements to come.
Sustainable housing development will lead to long-term cost savings, improve the durability of new homes and infrastructure, and contribute to a greener future.