Building to net zero: costing carbon in construction – Report Summary

Summary

The UK built environment is responsible for approximately 25% of total UK greenhouse gas emissions. The UK has a legally binding target to reach net zero by 2050 and at COP26 the Government committed to achieving 68% reductions in carbon emissions by 2030. This is only eight years away. There is little government guidance as to how these targets are to be met by the built environment industry.

This report examines how to improve sustainability of the built environment in the UK. Five broad themes are addressed: 1) accounting methods for embodied and whole-life carbon; 2) the use of low-carbon building materials; 3) government procurement of buildings; 4) issues surrounding retrofit and reuse; and 5) the skills and training required to delivered sustainable construction.

• Firstly, to date, policy has focused entirely on operational emissions, namely how to make buildings more energy efficient. The embodied carbon cost of the construction is not required by current policy to be assessed or controlled, other than on a voluntary basis. As a result, no progress has been made in reducing these emissions within the built environment. The construction industry is willing and able to undertake whole-life carbon assessments to measure the operational and embodied carbon cost of construction. The standards, methodology and reporting framework exists although it needs standardising, and the cost of undertaking assessments can be minimal. Other countries and some UK local authorities are already requiring whole-life carbon assessments to be undertaken. This leaves the UK slipping behind comparator countries in Europe in monitoring and controlling the embodied carbon in construction. If the UK continues to drag its feet on embodied carbon, it will not meet net zero or its carbon budgets.
• Secondly, there is availability of low-carbon building products to meet current demand, however there are insufficient incentives to develop and use these materials. Obstacles remain preventing the uptake of timber products in construction. This includes issues regarding fire risk and insurance, price volatility, securing sustainable and local supply chains, and addressing skills gaps in the use of timber. The Government has made little progress addressing these barriers in the last three years.
• Thirdly, the Government states it is promoting the benefits of re-using and retrofitting buildings ahead of demolition, but we have seen insufficient evidence of this being the case. The expansion of permitted development rights to allow for demolitions was introduced without proper consideration of its potential impact on carbon emissions and is resulting in buildings being demolished without understanding the whole-life carbon impact.

To address these issues, the single most significant policy the Government could introduce is a mandatory requirement to undertake whole-life carbon assessments for buildings. This requirement should be set within building regulations and the planning system. Following introduction of whole-life carbon assessments, the Government should develop progressively ratcheting carbon targets for buildings, to match the pathway to net zero. A clear timeline for introducing this should be set by the end of 2022. This policy will incentivise greater retrofitting, the development and use of low-carbon materials, and investment in low-carbon construction skills.

Alongside this key recommendation, there are a series of supporting policy changes that can further enhance the sustainability of the built environment. In particular, the Government should urgently undertake a full investigation into the impact extensions to permitted development rights (PDRs) has had on incentives to retrofit existing properties. PDRs should then be reformed to align with the Government commitment to promote reuse and retrofit ahead of demolition, if needs be.

The Government must also develop a coherent, joined-up policy to meet afforestation commitments and the need for commercial plantations to meet the demand for domestic timber in construction. The Government must invest now in further research and safety testing on the use of structural timber.

Ultimately, the carbon emissions associated with construction must be significantly and rapidly reduced if the Government is to meet its net zero goals. Introducing whole-life carbon assessments is a proven and widely supported way to transition to a low-carbon built environment. The Government must set out plans this year to make this a reality.