Written evidence submitted by WSP


WSP is pleased to submit its evidence to the Environmental Audit Committees study into the built environment. We welcome the decision of the Committee to consider changes the sector could make to achieve the government’s 2050 net zero carbon target.

About WSP

We are one of the world’s leading engineering professional services consultancies, operating across the built and natural environment. Our team of technical specialists and strategic advisers across the UK is part of a talented global family of expertise. Together, we ensure innovative solutions, solve complex problems for our clients and the communities we serve, meeting both the needs of today and addressing the challenges of the future. As the largest environmental consultancy in the UK, WSP takes pride in leading the way we collectively tackle the climate emergency across the build and natural environment. This is why WSP has more recently committed to halve the carbon footprint of all designs and advice provided to clients by 2030.


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

The CCC report Housing Fit for the Future states that by 2022, the UK’s 1.5m proposed new homes “must be low-carbon, energy and water efficient and climate resilient”. We (WSP) have yet to see significant evidence that any of the recommendations in relation to the voluntary reduction of embodied carbon have been embraced at scale.

Both industry and the domestic market lack regulation in relation to the lifetime carbon emitted in materials used in new buildings. On top of continued efforts to increase the use of green energy, the UK Government could look to implement a “fabric first” approach to new developments, and ensure this is properly enforced, whilst also introducing embodied carbon regulation to mirror the principles of Part L.


  1. 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?

Natural materials generally have the lowest carbon. A fabric first approach should be prioritised to essentially eliminate operational carbon, i.e., design the building so that it rarely needs to be heated or cooled.

Where carbon intensive materials are required, their utilisation should be limited through regulation as the UK is currently lagging behind its Paris commitments.

In relation to UK domestic dwellings, using the correct materials (natural materials) and utilising the technology that is increasingly available (i.e. insulation, heat pumps, green energy), is realistic and achievable.

Separately, on larger properties, the UK Government could consider requiring developers to model their builds using a 2050 weather file. WSP undertook related research a few years ago on overheating in London’s buildings, producing a White Paper: “Overheating in Homes”. WSP’s research suggested that active cooling within properties may be the only answer in some situations and in the future, but it should be seen as a last resort. Efforts should instead be made to encourage the use of passive solutions within innovative building design. There are many examples of Passivhaus buildings that prove the technology exists, but this requires employing at scale.

Crucially, higher standards in housing do not have to translate to higher pricing for consumers. The value is in the price of the land. The UK Government needs to encourage a shift in the perception of pricing in this context.


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

It must not be overlooked that, as is the case with achieving the Government’s net zero ambitions, they will only be met if a multitude of avenues and channels are considered. Increased conversation about the use of natural materials is encouraging, but greater uptake is necessary.

Timber is a traditional material which has been in use in the UK for thousands of years. We now need timber production at scale and also clarity on whether future regulation could render this material unusable in the post Grenfell environment. Already a number of buildings are being designed that utilise these materials, and a larger scale up is achievable if the industry receives long term confidence.


  1. 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?

Decarbonisation of the whole supply chain is the critical issue that is currently being overlooked. Having observed how the Land Fill tax and tightening of Part L acted as a catalyst for change in material disposal and reduction in operational carbon, the time is right to regulate embodied carbon across all sectors of the build environment.

Currently, there is carbon wasted in trying to achieve regulations. All new buildings should be regulated to adhere to Net Zero design requirements, which would drive the reductions in carbon (both embodied and in operation) and to further avoid expensive and disruptive retrofit.

Furthermore, voluntary codes have failed to deliver the significant improvements required to address the existential threats associated with the climate emergency for the vast majority of new developments.

In order to deliver a more sustainable built environment, there also needs to be an increased focus on measurement, in order to check standards and targets have been met. For example, there is often a gap between the theoretical number of houses that can be delivered and the physical number. Some other options that could be further required are the improvement in the regularity of spot site inspections, or more simply, the need for photographic evidence when thermal elements are installed.

There is also a lot to focus on in relation to local authorities. WSP was encouraged to see further autonomy granted to local authorities on setting their own environmental standards for their locality. However, many need further support in implementing and financing their standards to incentivise change amongst developers. This would then enable them to make best use of the freedoms they have long been granted.


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

There is extensive guidance from institutions like the London Energy Transformation Initiative and Royal Institute of Chartered Surveyors.

Low carbon assessments are being undertaken under the London Plan and the lessons these institutions and bodies are learning should be incorporated into UK wide regulation without delay.

Alternatively, Sweden also has an A-G rating for embodied carbon in buildings, which the UK could look to adopt.


  1. 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?

The Institute of Structural Engineers has instigated a SCORs system to grade the levels of embodied carbon within the structural frame of a building, similar to the labelling found on an electrical appliance. Incorporating this into the sales of all new and refurbished buildings in particular will assist customers in understanding the damage their potential purchase has made and help to drive up standards.


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

WSP has been encouraged by the inclusion of a biodiversity net gain requirement, as proposed in the Environment Bill, as a condition of planning permission in England. Generally, the inclusion of green infrastructure is very mixed. Some developers and clients are aware of the health and wellbeing benefits and are willing to incorporate them into their design to deliver high quality developments. However, many developments are purely designed to very weak and unfit building regulations which mean the value adding items are never considered.


  1. 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?

The design principles are well understood with the construction industry. The challenge is that the existing voluntary codes have no robust mechanisms to drive better behaviours into every sector of the industry. At present the London plan is enforcing a 40% betterment for operational carbon beyond Part L. Regulation should be challenging and a driver of best practice rather than being so outdated that it is essentially meaningless.


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

The UK Green Buildings Council has suggested that 80% of the buildings required in 30 years’ time have already been built. Therefore, the re-use and refurbishment of existing stock needs increased focus.

With extensive analysis indicating a large percentage of a building’s whole life carbon being generated during construction, the demolition and replacement of existing buildings should always be the last option available. The reuse and repair of our existing building stock is of paramount importance. We must remember that every consumption has a cost.

In city centres, the retrofit of existing buildings can bring a variety of benefits. A WSP report, Rethinking Retrofit, gathered the thoughts of UK architects and property developers, as well as public and private sectors experts. WSP found that retrofitting can save space in our overcrowded city centres by solving the need for new buildings – and even help tackle the rising problem of loneliness by offering residents proximity to public transport, amenities and social spaces.

New developments may be required, but then should conform with higher net zero carbon building standards, and the suggestions in the above-mentioned WSP report, i.e. building on spaces with existing social infrastructure and amenities (convenient for communities but can also improve wellbeing). Also, where appropriate also including digital technologies and platforms that will help control how buildings operate so they that they constantly balance the changing demands of occupants.

In housing, the permitted development approach can leave us at risk of achieving a poorer quality of housing. Careful thought needs to be encouraged when converting from commercial to residential, in regard to placemaking and the balance of housing and commercial sites, and the difference in quality of materials required for the two types of property.

If the scale of permitted developments does increase whilst only the standards required for new builds actually improves, the standards of permitted developments will become relatively lower. We need to consider how to better equalise the standards across both new and existing buildings.


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


May 2021