Rockwool                            SBE0058

Written Evidence Submitted by ROCKWOOL Ltd



ROCKWOOL Ltd is part of the ROCKWOOL Group. With more than 11,500 colleagues in 39 countries, the ROCKWOOL Group is the world leader in stone wool solutions. ROCKWOOL Ltd is the UK's leading manufacturer in sustainable stone wool insulation materials for thermal and acoustic purposes as well as fire resilience. Our insulation is non-combustible and is produced at our factory near Bridgend, South Wales.

ROCKWOOL Ltd welcomes the opportunity to respond to the Environmental Audit Committee’s call for evidence on sustainability in the built environment. We are committed to reducing the environmental and climate footprint of our operations, and have set ambitious sustainability goals in line with this commitment. Last year the ROCKWOOL Group announced ambitious new science-based global decarbonisation targets that equate to a one-third reduction in our lifecycle emissions. The new decarbonisation commitments build on ROCKWOOL’s existing status as a net carbon negative company, in that over the lifetime of its use, the ROCKWOOL insulation will save 100 times the carbon emitted in its production.

To what extent have the Climate Change Committee’s recommendations on decarbonising the structural fabric of new homes been met?

The Climate Change Committee (CCC) wrote to the Ministry of Housing, Communities & Local Government (MHCLG) in February 2020 in response to the proposals for the Future Homes Standard,[1] outlining concerns that the proposals would not go far enough to reducing carbon emissions from the UK’s built environment.

Some of these concerns have been addressed through MHCLG’s response to the Future Homes Standard consultation, including the retention of the Fabric Energy Efficiency Standard which ROCKWOOL strongly supports. Initial plans to remove this could have inadvertently resulted in homes being built to lower fabric energy efficiencies than current standards require.

However, some of the concerns raised by the CCC have not been addressed. In particular, the CCC has called for a framework for reducing the whole-life carbon impact of new homes, including assessing carbon emissions associated with the building materials used, but MHCLG has only committed to further examining low carbon materials in the longer term. Our own views on assessing the whole-life carbon impact of buildings are addressed later in our response.

The CCC has also raised the broader issues of needing to improve in-use performance in the Building Regulations for new homes.  We agree and believe operational targets should be introduced by 2025 to close the gap between as-designed and as-built performance. This will be critical to meeting carbon reduction targets. If we continue to assess building performance based on theoretical carbon savings whilst buildings are not in reality meeting the energy efficiency standards government sets, this will create a deficit in emissions reductions that will become difficult to address.  

How can materials be employed to reduce the carbon impact of new buildings, including efficient heating and cooling, and which materials are most effective at reducing embodied carbon?

Embodied carbon should not be considered in terms of a finite measurement undertaken when construction is complete but considered across the lifecycle of a building. When buildings fail to fulfil their function, they become obsolete. Keeping buildings in service for longer, making them durable and flexible to adapt to changing needs has a lower carbon impact over time. In terms of the material choices being made, embodied carbon must be considered alongside questions such as what function they perform in the building, durability and consistency of performance.

ROCKWOOL stone wool insulation is a net carbon negative company, saving 100 time more carbon that is emitted during its production, including upstream impacts from raw material extraction, processing and transport. Therefore, the embodied carbon within the product is ‘paid back’ in terms of avoided emissions within a few months. When fitted correctly and left undisturbed, ROCKWOOL will continue performing for the lifetime of the building without degradation in performance, thereby helping to prevent a building’s thermal performance from declining over time and reducing the need to replace old material with new.

Some materials can also perform many functions in a building, thereby leading to material efficiencies. For example, ROCKWOOL stone wool insulation provides both thermal and acoustic benefits, meaning in some applications you can avoid the need to install additional acoustic layers to achieve a good level of acoustic performance.

Further, product environmental data must be robust and of a consistent quality to enable decision making. As a minimum it should cover the full lifecycle of the product, including raw material extraction, processing and transport and the impacts arising at end of life. It should also cover a broad range of environmental impacts. There are many factors that cause environmental harm beyond carbon and so too narrow a focus can lead to unintended consequences in other areas.

What role can nature-based materials play in achieving the Government’s net zero ambition?

All sectors and industries have a role to play in achieving the Government’s net zero ambition. There is not a silver bullet to achieving net zero, nor can one industry be singled out as they key to driving down emissions. Manufacturers of building materials of all types will need to look at their performance and consider how it can be improved.

The ROCKWOOL Group has integrated circular economy principles into our business model. ROCKWOOL stone wool insulation is manufactured from an abundant natural resource, volcanic rock, which is continuously replenished through volcanic activity. We are able to incorporate industrial waste such as steel slags in our production process along with virtually all of our own production waste, reducing the overall demand for landfill. Our product is engineered to perform consistently for decades and is infinitely recyclable with no deterioration in performance. We are already a net negative company as detailed above but we are going further with ambitious Science Based Targets initiative verified and approved decarbonisation goals which will lead to a one third reduction of our greenhouse gas emissions across scope 1, 2 and 3 and places us on a net zero trajectory.

Additionally, we are looking at the role we can play to support decarbonisation in our region. ROCKWOOL is an active partner in the South Wales Industrial Cluster, a grouping of industry, academia and utilities working in collaboration to develop a pathway for industrial decarbonisation and increasing the circular economy. This will have the effect of driving down the embodied carbon of a range of materials, including those used in construction, as well as securing continued investment in manufacturing in the UK.

What role can the planning system, permitted development and building regulations play in delivering a sustainable built environment? How can these policies incentivise developers to use low carbon materials and sustainable design?

Building regulations have a critical role in setting standards around operational energy and emissions. However, embodied emissions resulting from the extraction, manufacture and assembly of materials plus maintenance and end-of-life disposal account for up to half of the overall carbon emissions of new buildings. Therefore, embodied carbon will need to be addressed to achieve net zero carbon emissions in the built environment. We agree with, amongst others, the Climate Change Committee that embodied carbon should be included in a wider conception of the Future Homes Standard and Future Building Standard.

The introduction of mandatory targets, however, must be gradual with a clear road map from widespread assessment of embodied carbon emissions, to disclosure, to mandatory targets. The framework for assessing, reporting and reducing embodied carbon in the built environment does not yet exist and there are a number of factors that need to be considered before targets could be introduced, including the development of a standardised method  to calculate the carbon emissions associated with construction products and ensuring there is high quality, accessible, data for all products associated with a building.

It is also important that operational energy and emissions are not downgraded in a drive to address embodied carbon. Whilst emissions associated with embodied carbon will become even more important as operational emissions reduce, there is still much work to be done to reduce operational energy use in buildings. There is a widely acknowledged gap between as-designed and as-built energy performance which will be critical to meeting carbon reduction targets. It is vital that the combined impact of operational and embodied carbon is considered when setting targets.

Further, a sustainable built environment should be considered more than just reducing energy use and carbon emissions. We believe the Future Homes Standard and the Future Building Standard provide an opportunity for building regulations to consider buildings holistically and design a future standard that aims to deliver efficient, healthy, comfortable and safe buildings. This means, for example, ensuring comfortable internal temperatures throughout the year, high levels of energy efficiency, good indoor air quality, adequate protection from noise and a high standard of safety in the event of a fire. Building materials should be chosen based on how they deliver across the range of these performance metrics. 

There will be other respondents who have more expertise to comment on the planning system and permitted development, but we have supported work by the UK Green Building Council to support to local authorities to embed sustainability in their planning policies and would direct the Committee to that work: We also share many concerns with organisations such as the TCPA and RIBA regarding the decline in quality of homes built through the conversion of commercial buildings to dwellings through permitted development and would encourage the Committee to consider how higher standards could be achieved through the permitted development process.

What methods account for embodied carbon in buildings and how can this be consistently applied across the sector?

Any new requirements on embodied carbon will need to be accompanied by a robust accounting methodology capable of covering the full lifecycle of a building and sophisticated enough to highlight the full impact of changes to product specification. As highlighted above, ROCKWOOL stone wool insulation can provide thermal and acoustic benefits and is naturally non-combustible. Using a different product type may require the use of additional materials with their own embodied carbon to achieve the same level of acoustic performance or to attempt to improve fire safety.

There are currently significant gaps in the availability and quality of environmental data which will need to be addressed prior to the introduction of requirements. This is to avoid the risk of businesses that have invested in having robust and transparent assessments being disadvantaged by companies producing ‘favourable’ data that has not subject to the same quality standards. We strongly support the use of third party verified BS EN 15804 compliant Environmental Product Declarations (EPDs) to communicate environmental data across all lifecycle stages.

Should the embodied carbon impact of alternative building materials take into account the carbon cost of manufacture and delivery to site, enabling customers to assess the relative impact of imported versus domestically sourced materials?

Embodied carbon is a measure of the carbon dioxide (and all other greenhouse gas) emissions associated with the full lifecycle of a product. That includes lifecycle stages such as raw material extraction, processing, transport, manufacture, distribution, installation, in use (e.g. maintenance) and disposal at end of life. Any measure which fails to take into account the carbon cost of manufacture and delivery to site would not be a true metric of embodied carbon. Furthermore, ignoring any lifecycle stage through to end of life does not present a complete picture of a product’s impact. This could lead to the selection of materials on the basis of low embodied carbon in some lifecycle stages, but which have a far greater impact when all lifecycle stages are accounted for. In particular, we frequently see that end of life impacts are not assessed or not declared, meaning a significant contribution to lifecycle embodied carbon is missed.

The use of BS EN 15804 compliant EPDs as the basis on which to determine and communicate environmental impact should take into account all of the relevant lifecycle stages and looks across a range of environmental impacts. This would mitigate the risk of unintended consequences so that the pursuit of reducing embodied carbon does not lead to environmental harm in other areas.

How well is green infrastructure being incorporated into building design and developments to achieve climate resilience and other benefits?

Not within our area of expertise.

How should we take into account the use of materials to minimise carbon footprint, such as use of water harvesting from the roof, grey water circulation, porous surfaces for hardstanding, energy generation systems such as solar panels?

Not within our area of expertise.

How should re-use and refurbishment of buildings be balanced with new developments?

We believe that both re-use and refurbishment, and new developments, have a role to play in growing the building stock. According to a recent House of Commons Library briefing[2], an estimated 345,000 new homes are needed a year to meet housing needs. The scale of need means new build housing will be necessary, but with an estimated 50,000 buildings demolished every year[3], clearly the re-use of those buildings could contribute to the housing deficit. Not all buildings will be suitable for reuse but building skills and techniques have developed to the extent that even complex high-rises are suitable for renovation.

Compared to demolition and rebuild, re-use is a more sustainable option. Existing buildings have already produced carbon during construction and so there is a strong case for ensuring that they last as long as possible. Demolition requires energy to tear down a building and dispose of the waste, with a replacement building then requiring more materials and energy, all creating more embodied carbon.

Going beyond sustainability, re-use and refurbishment can have other positive benefits. Re-use can be more cost-effective. We were recently involved in the major refurbishment undertaken by Portsmouth City Council of Wilmcote House – an 11-storey social housing block that was renovated to the ambitious EnerPHiT standard. Accounting for the cost of demolition, rebuilding, disturbance allowance and rent loss, and the savings on building maintenance, the council decided that a deep, high quality refurbishment was cheaper over a 30-year-plan than demolition and replacement[4].

Re-use of the building is often preferred by the residents who often want to stay within the local community. In the Wilmcote House example, residents strongly support the overall approach of Portsmouth City Council to the estate renewal. They liked the location of Wilmcote House, its proximity to schools, shops and the station. Other benefits to refurbishments include savings in energy bills due to increase energy efficiency of the building, improved health and wellbeing associated with improvements to the buildings (i.e. mould and draughts) and increase comfort levels for residents.

What can the Government do to incentivise more repair, maintenance and retrofit of existing buildings?

To meet the reduction in emissions required by the Climate Change Act, there will need to be significant improvements to our existing building stock. 80% of the UK’s existing stock is likely to still be in place in 2050 and there must be a clear roadmap to improving the energy efficiency of those buildings alongside building better performing new ones. The scrapping of the Green Homes Grant voucher scheme has left a major policy and funding gap for improving the energy efficiency of existing homes. 

ROCKWOOL UK is an active member of the Energy Efficiency Infrastructure Group (EEIG) a coalition of over 25 industry groups, NGOs, charities and businesses. We fully support EEIG’s recommendations on making energy efficiency a national infrastructure priority and developing a Buildings Energy Infrastructure Programme to support energy efficiency retrofit in homes.[5] The group’s recommendations to Government include developing improved incentives and financial enablers to encourage building owners to undertake energy efficiency improvements to domestic and non-domestic buildings, such as Green Stamp Duty, capital allowances for energy efficiency upgrades for landlords, and zero rate VAT for renovations. A reduced VAT rate for renovations would also act as an incentivise to building owners to repair and retrofit of existing buildings over demolition and rebuild. There is currently a 20% VAT levy on refurbishments as opposed to 0-5% on new build, creating an incentive for new build over refurbishment, which as we outlined earlier in our response can often be a less sustainable option.

May 2021






[5] See full recommendations here: