Blog Post

Can sub-dividing properties help to meet housing need within carbon budgets?

All those engaged in the debate about the shortage of decent housing, and lend support to the building of new houses, should be taking into account the carbon emitted in housebuilding and the associated services and infrastructure.  “Building not blocking” might be a great electioneering slogan but suggests the Labour is looking to side step the need to reduce carbon emissions. 

Embodied and operational carbon attributable to housing is a significant contributor to the UK carbon budget and all housing strategies should include measures to reduce this to zero.  Research led by Dr Zu Ermgassen, from the University of Kent has shown that the emissions from building 300,000 houses per year would amount to 113% of the country’s whole carbon budget. He concludes that, “…England can’t go on building new houses forever, and needs to start thinking about better and more systematic solutions as to how we are going to house everyone within our environmental limits”.

These findings mirrored those of the UK Green Building Council Net Zero Carbon Buildings Framework 2019 which points out that, “Annual embodied emissions alone are currently higher than the Green Construction Board’s target for total built environment emissions by 2050.” And it is far more urgent to reduce embodied carbon that, being emitted in the short term, stays in the atmosphere while operational carbon from new and existing stock can be avoided or mitigated in the medium and longer term.

The Communities Select Committee looked at housing and concluded that,  “To meet its target to eradicate the UK’s net contribution to climate change by 2050, the government should embrace every opportunity to reduce carbon emissions. It should be ambitious in setting carbon reduction targets for the built environment both during construction and in use (emphasis added). The building regulations should set more stringent energy performance targets for homes to take into account achievable levels of energy efficiency. Modern Methods of Construction (MMC – or prefabrication) should be used to deliver more efficient homes now to avoid costly retrofitting of homes later to comply with more rigorous energy efficiency targets.”

But there is no sign the Department will rise to the challenge of its own Select Committee. The latest revision to the building regulations does not include embodied carbon since it is not considered to be a matter of safety or how the buildings are used.

Homes England (HE) Strategic Plan 2023 -2028 sees the need for an, “indicator to be developed on embodied carbon of HE supported development.” But HE also say that will be the job of the Department of Levelling Up, Housing and Communities who have consistently kicked it down the road, to be dealt with after the Future Buildings Standard comes into effect in 2025. Progress is being made on developing the reliable metric that DLUHC use an excuse for the delay but meanwhile, new building continues using materials with high carbon intensity.  At the same time new housing is skewed towards the private demand for larger and instantly under-occupied homes rather than the general housing need for 2 bedroomed properties requiring less carbon to both build and maintain.

This is a challenge to those who think that building 300,000 new dwellings in England each year is the way to address the housing crisis/shortage, particularly if these involve new settlements with even higher carbon costs for infrastructure.  Furthermore, buildings with added PhotoVoltaics (PV) may represent the best chance of reaching ‘carbon negative’ or ‘energy positive’ given the problems being faced by transport, manufacturing, power generation, agriculture and the military. Finally, climate justice dictates that the UK has to lead while expecting less from countries that never benefitted to the same degree from cheap fossil fuels.

If new housing is to continue, there will have to be a scaling up of the use of timber (subject to trusted sustainable supplies), stone, slate, lime based mortar and renders, and low/zero carbon renewably powered MMC.  There are unlikely to be low carbon substitutes for the cement, steel, aluminium, glass and the concrete being used in services like roads and drains. 

Rather than expecting new building to solve the housing crisis, and continuing to complain about the planning system, the shortage and cost of suitable land on which to build houses, the cost of materials and the shortage of suitably skilled labour, there should be greater focus on the potential for sub-dividing existing under-occupied properties.

There are about 28m dwellings and about 27m households, confirmed by the English Housing Survey research which estimates there to be 1.2m empty or underused homes.  That research does not reveal the ubiquity of under-occupancy where about 50% of bedrooms are not being used as such.  Under-occupation is not just confined to villages and rural areas where the most common form of housing has two spare bedrooms. One way to redistribute the housing space that already exists, almost all of which is in need of a deep energy refit during the next decade, is to concentrate resources, finances, fiscal policy and regulations on subdividing existing properties.   Research carried out for The Intergenerational Foundation suggested that there are over 4m dwellings suitable for sub-division that would amount to over 12 years’ supply of low carbon dwellings if the need is for 300,000 per year.  The need is greater for these smaller dwellings but the process would include down-sizing that would release a good number of family size dwellings.

In 2016 the All-Party Parliamentary Group on Housing and Care for Older People received evidence that there could be as many as 8 million households looking to downsize and waiting for attractive smaller dwellings to become available.  Some of these households could be keen to downsize–in-place enabled through sub-divisions, some of which could accommodate some of the increasing number of concealed households comprising young adults living reluctantly with their parents, and provide them with greater independence and financial security than enjoyed as lodgers.  The increase in residential densities could also fit the agenda of those advocating for 20min or lifetime neighbourhoods. The many other co-benefits are described in this blog.

A requirement is set out in the Housing and Planning Act 2016 (as amended) to grant planning permissions for sufficient serviced plots to balance the registered demand for self or custom build housing. Without a serious review this statutory requirement will remain unrealistic, little known and discredited.  However, if those languishing on the statutory self-build registers, with diminishing prospects of being found a serviced plot, can assist in this process of sub-division  (by ‘custom-splitting’), then the transition to low, zero, and then negative carbon housing could have multiple benefits.  Councils could assist in this process by keeping a register of those with space to spare they would ready and willing to share. Grants and/or loans could be made available for sub-divisions to cover the costs of feasibility studies, surveys, specifications and planning and building regulation applications.  These upfront costs could be recovered as a charge against the properties were one or both to be sold on.

Daniel Scharf MRTPI is a director/volunteer at one Planet Abingdon Climate Emergency Centre and blogs at

Blog Post

Tackling the Environmental & Housing Crisis: The Case for Green Homes

Coronavirus has upended everything. Within the space of a week in the spring, the pandemic has taken centre-stage in our social and political lives and has remained there, immovable, ever since. So interwoven into the experience of everyday life has the virus become, it sometimes feels difficult to think about much else.

In many ways it’s absolutely right that our attention should be so fully devoted to discussing covid-19 and, in particular, how to contain it. Bearing down on the spread of the virus to protect life and jobs is arguably the single biggest challenge the country and the world has faced since WW2.

But there are two additional crises that lurk not far into the horizon. In fact they are already here. These are the dual threats of the housing crisis on the one hand, and environmental collapse on the other. As scientists have evidenced, the latter creates the conditions for viruses like covid-19 and others to spread in the first place.

Left unchecked these twin crises will get worse and spin out of control.

Just consider this. It’s possible that environmental degradation could lead our planet close to becoming uninhabitable by the end of the century. The destruction of nature isn’t just about climate change — undoubtedly an existential risk and one that has received a lot of attention since last year. It’s also about extreme biodiversity loss and a rapid decrease of land and soil productivity — two issues which get too little attention and which, in the words of the UN, are “eroding the very foundations of our economies, livelihoods, food security, health and quality of life worldwide.”

On the other hand, the collapse of affordable housing has proved a disaster for many and may get worse. Home-ownership is out of reach for a generation of young people, in parts of the country average rent equates to three-quarters of median pay, and tens of thousands of families live in insecure temporary accommodation. Without access to a place people can reliably call home, the foundations of democratic norms — norms which rely on basic levels of socio-economic security for all — are at risk.

But this needn’t be our fate. We can carve out a different future, one where we provide housing security for everyone and safeguard nature at the same time. Doing this requires implementing a wide range of governmental interventions and creating market conditions which favour people and the planet above unbridled profit. But there is one policy area where we can begin to tackle both crises at once — and that’s unlocking the potential for environmentally friendly housing while making housing genuinely affordable.

So how do we do it?

Change begins with shifting how we think about housing. Much of the debate frames environmental protection and boosting housing supply through the prism of trade-offs: we sacrifice the former for the latter (or the reverse), say by building on the green belt (or choosing not to). But new-build and enhancing environmental protections can be two sides of the same coin.

Indeed, innovation and policy change is already moving us in that direction. Some developers are incorporating enhancements to ecosystems within their developments, like increasing beehives and bird boxes in urban settings. In parallel, bodies like the London Assembly champion ideas to nudge or require developers to think green — like incorporating requirements for minimal ‘green space factors’ into planning and recognising innovative ideas through award schemes.

In addition, the more we can transform the infrastructure that neighbourhoods rely on towards sustainable ends, the more we can move in this direction. For instance, we must ensure transport links are green — whether it’s by prioritising walking and cycling links above roads, and when roads are necessary ensuring they’re used by electric cars, not gas-guzzling vehicles.

A second step lies in pushing back on historic, out-dated practices in the development industry. At the forefront of this change is challenging a de facto presumption in favour of demolition. Demolition is massively wasteful — in the UK alone, the construction industry accounts for 60% all materials used. In addition, the development industry accounts for 45% of carbon emissions, and when demolition happens it releases huge amounts of “embodied carbon”. The alternative should be a presumption in favour of refurbishment with demolition there as a genuine last resort.

It is possible to refurbish whilst unlocking affordable housing. The long-term consequences of covid are likely to be empty office buildings in the centre of cities, as white-collar workers shift to working from home on a more regular basis. Local and regional leaders must therefore find ways of bringing back empty premises into use as affordable and quality housing. We’ve already seen councils take similar steps to revitalise centre city living when perceived urban decay has been a challenge in the past.

In cities like Liverpool city centre, living increased by 181% from 2002 and 2015, whilst in Birmingham it increased by 163%, and these changes were a result of proactive policy interventions. Living in these areas is now associated with a good quality of life, in effect embracing the Mayor of Paris’ 15 minute living concept where everything one would need (whether it’s access to gyms, restaurants, the supermarket, or schools) is within close walking distance.

A third move is embedding the circular economy into any new affordable housing development. From deploying renewable energy sources, like heat pumps and solar, through to releasing more subsidies for insulating homes, change is well under-way on this front. The shift needs to be coupled with sustainably disposing of waste and in particular food waste — an issue that lies behind a whopping 8% of global greenhouse gas emissions.

What this means is getting people to waste less food in the first place, and when waste is inevitable making sure it’s composted or ends up in anaerobic digestion plants not landfill or being incinerated. Crucially, using resources intelligently helps with the affordability of living expenses. Cutting fuel bills can lead to hundreds of pounds in household savings, whilst eating not wasting edible food can save the average household £500 per year.

These are just some changes that we can make to marry the need for genuinely affordable housing with sustainability. What’s outlined above does not negate how difficult achieving the scale of transformation we need to see will be. But the urgency with which we increasingly understand the environmental crisis, coupled with new technological opportunities, means citizens, policy-makers and developers are very clearly beginning to envision and see the opportunity to build another future.

This week Labour challenged the government to ‘Build it in Britain’ and support the creation of 400,000 jobs, including in the crucial manufacturing sector, through a green recovery from the Covid crisis. Action now would support the creation of new jobs and tackle the climate and environmental crisis, and includes expanding energy efficiency and retrofit programmes, including in social housing.

For too long we’ve negated people’s right to secure housing whilst undermining the natural world. Covid-19 is undoubtedly the biggest short challenge facing us, but we need to walk and chew gum at the same time, keeping focused on tackling the twin threats of insecure housing and environmental breakdown.

The moment for change is now.

<strong><span class="has-inline-color has-accent-color">Pancho Lewis</span></strong>
Pancho Lewis

Pancho Lewis is a Westminster Councillor, where he is Shadow Cabinet Member for Environment, and works for the food waste start-up Too Good To Go.