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What are sustainable building projects?
Sustainable building projects utilise low embodied carbon building materials, high levels of insulation, and the integration of renewable energy sources. These projects are increasingly prevalent within the local authority sector to meet legal net-zero requirements.
Legal requirements under:
- England, Wales & NI:
- Net-zero mandate with 2050 target.
- Part L of Building Regulations (2021/2022 update): New dwellings must achieve roughly a 30% reduction in CO2 emissions, and non-domestic buildings a 27% reduction compared to previous standards.
- Scotland:
- Net Zero Public Sector Buildings Standard. Applies across all new, or major refurbishment projects. All public sector buildings to achieve net zero emissions by 2045.
Sustainable building projects utilising combustible building materials are more likely to experience a total loss due to fire. The frequency of fires in these buildings is higher due to the integration of renewable energy systems. The insurance market is wary of these new developments, and adequate cover is only provided for those with an acceptable level of protection.
The difficulty that insurance companies have with modern sustainable buildings can be compared to the story of The Three Little Pigs. The wolf can easily tear (burn) down houses made of straw and sticks but cannot destroy the house made of brick. The use of sustainable building materials and practices must be balanced with safety and risk management.
There have been several notable UK fires at premises with sustainable construction:
- The Promise School in Okehampton, Devon (2026) – A timber framed school with high levels of insulation and a roof mounted photovoltaic system.
- Beechmere Care Home, Crewe (2019) – A timber framed care home without sprinkler protection.
- Carbon Neutral Laboratory, Nottingham (2015) – A new development which suffered a fire from an electrical fault whilst construction was ongoing. A lack of complete fire compartmentation or fire suppression systems contributed to the total loss.
It is important to question the sustainability of these buildings. These buildings may have seen smaller losses from improving compartmentation, utilising non-combustible building materials, or the installation of a sprinkler system. Insurance companies, architects, and local authorities must learn from these fires to prevent future developments suffering the same fate.
Primary risks in modern construction
- Low embodied carbon building materials.
The amount of embodied carbon contained within building projects is a key sustainability target for public buildings. Traditional building materials such as concrete, steel, aluminium and mineral wool insulation have high embodied carbon. The production, transportation and disposal of these materials produce high greenhouse gas emissions. Building materials with low embodied carbon include timber, straw, hemp and sheep’s wool insulation. The performance of these materials regarding Reaction to Fire Testing is generally inferior to materials with a high embodied carbon. Reaction to Fire Testing to BS EN 13501-1 determines the combustibility and ignitability of a material and is a key metric insurers will use when evaluating new building developments. Materials such as recycled glass wool, clay bricks or rammed earth strike a good balance between combustibility and embodied carbon. The re-use of existing materials in refurbishment projects helps to minimise the total embodied carbon.
- High levels of (combustible) insulation.
Sustainable building projects utilise high levels of insulation to reduce energy consumption over the building’s lifetime. This provides further challenge, as insurers evaluate the quantity and thickness of insulation used in these projects, for example, 50mm of sheep’s wool insulation presents a lower fire load than 150mm of the same insulation.
- Renewable energy integration.
The integration of renewable energy systems augments the reduction of energy consumption over the lifetime of the building. The addition of roof mounted photovoltaic systems, heat pumps, battery storage systems, or electric vehicle charging facilities add ignition sources to developments, and the risks associated with these must be mitigated accordingly. Consultation with the property insurer is critical for the integration of these systems.
- Build quality.
As important as the above points is whether the structure is built to designed specifications. Third party certification of all fire protection measures incorporated into a sustainable building project is critical. Correct cavity barrier placement and fire stopping is vital to delay the spread of fire in these buildings; verified via photographic evidence. Build quality is highly dependent on the competency of installers and Clerk of Works.
Involve your insurer
Sustainable buildings are at higher risk of significant losses than those made of non-combustible materials. As insurers, we want to enable sustainable building projects, and the best way to ensure that these buildings will stand the test of time is through early engagement and collaboration with your property insurer.
