Could a new concept in refurbishment help to alleviate the UK’s serious shortage of warm, sustainable and affordable homes? Melanie Thompson of Get Sust! externallink investigates.

Housing is always in the news, typically focusing on rising prices (in the south east). But with just five years to reach our emissions-reduction targets and as the nation’s politicians dust off their soap-boxes ready for the May General Election, it is time for everyone to focus on the other aspects of housing – accessibility and sustainability.

According to recent reports by housing charity Shelter, and the social justice experts at the Joseph Rowntree Foundation (JRF), the UK has endured four boom and bust cycles in the housing sector since the 1970s. The results are massive financial gains for some lucky homeowners, but misery, uncertainty and homelessness at the other end of the scale, with the proverbial squeezed middle uncertain of the future (In the Mix: the need for a diverse mix of new homes externallink).

At the start of the recession, the number of new homes being built in England fell to its lowest peacetime level since 1924 and things have barely picked up since then. The result is that each year more people are being priced out of home ownership, which in turn results in higher rents and increasing competition (and therefore shorter-term rental contracts).

The JRF housing market policy briefing externallinksays that by 2020 the number of home owners under the age of 30 will be reduced by almost a half, and an extra 1.5 million people under 30 will be competing for homes in the private rented sector.

New shoots in the home counties

The Coalition government has taken steps to counter the slow-down in building new homes, most recently by fast-tracking the development of two new ‘garden cities’ – 15,000 homes in Ebbsfleet, Kent and 13,000 in Bicester, Oxfordshire. These schemes will benefit from a £2 billion government investment externallink aiming to build an average of 55,000 new homes per year until 2020.

But this and other government-backed schemes announced recently will struggle to meet the target of 250,000 new homes that should be built each year simply to keep up with changing demographics (increasing population, ageing population, trend towards smaller family groups and so on).

House building at North West Bicester is already underway, where 6,000 dwellings will eventually form the Exemplar ‘eco town’ part of the 13,000 total. The first phase will comprise almost 400 zero carbon homes externallink (Code for Sustainable Homes, Level 5), powered by a district heating system and the UK’s largest domestic solar energy array 17,500 m²). Only 119 of these new homes will be in the “affordable” bracket externallink, though.

Which begs a number of questions – ranging from why is only half of the proposed total earmarked as an ‘eco town’, to whether public money could be better spent by targeting the refurbishment of existing homes across the country.

Undoubtedly, there is a significant need for new housing in strategic areas, so new build is essential. Such schemes are also likely to be beneficial in terms of sustainability because they will need to meet current (higher) standards than most existing developments. But new housing schemes such as this will barely dent the UK’s challenging 2020 target to reduce greenhouse gas emissions by 20% compared with 1990 levels – and that’s before we take into account that there are new goals with the EU-wide target of a 40% cut in total emissions by 2030 externallink, agreed in October 2014.

Mission impossible?

Almost a quarter of annual UK carbon emissions can be attributed to housing, and our existing dwellings are generally less energy efficient than those of our European neighbours, so the current target does seem daunting, and the new one even more so. We have known about the former for long enough, but now there are just five years left to meet the 2020 deadline. Can we do it?

It certainly won’t be easy.

In essence, the target could be achieved by two routes: either reduce energy consumption in all homes by 20%, or ensure that 20% of all homes are zero carbon.

So far we have relied on a ‘mix and match’ approach, combining the grey art of market transformation – trying to gently persuade homeowners and occupiers to invest in energy-saving techniques and technologies, with some tempting subsidies to sweeten the deal – and gradually tightening the energy-efficiency requirements for new homes. For a wide range of reasons this strategy is not delivering the goal. Time for a rethink.

In June 2014, the UKGBC in collaboration with 19 other charities launched a campaign calling on all the UK political parties to adopt a strong stance on refurbishing the housing stock, specifically:

“Achieve 1 million deep retrofits each year by 2020, including at least half a million retrofits every year to bring all low income households up to a minimum of Band C energy performance certificate (EPC) by 2025.”

The campaign’s report, A housing stock fit for the future: Making home energy efficiency a national infrastructure priority externallink says that this proposal makes sound economic (and political) sense for a number of reasons:

  • Government figures show that 2.5 million households in England are classified as being in fuel poverty in 2014, and energy efficiency measures could permanently reduce energy bills by £300 each year – lifting 9 out of 10 homes out of fuel poverty;
  • The UK could reduce its reliance on imported gas by 19 per cent, saving £2 billion in gas imports every year and simultaneously improving power security;
  • It could almost double the number of jobs in the sector to 260,000.

In summary, the report concludes that addressing domestic energy efficiency is one of the most cost-effective ways to achieve the target, with numerous added benefits. And a new study from the Netherlands puts forward an interesting proposal for how we might achieve this.

Writing in the journal Building Research & Information, Ronald Rovers reports on an innovative scheme to carry out the sort of ‘deep retrofits’ mentioned by UKGBC, at breakneck speed and without the need to move the occupants out of the buildings.

The pilot project described by Rovers (based at the Research Institute Built Environment of Tomorrow (RiBuilT), Zuyd University of Applied Sciences, Heerlen) saw 150 x 1970s housing association properties brought up to Passivhaus externallink standard in just 10 days, using a ‘renovation train’ approach.

Hestia, the Dutch housing corporation behind the pilot project at Kerkrade-West, knew from previous retrofit projects that decanting occupants was stressful and expensive. They decided to aim for a ten-day (two working weeks) process, agreed in consultation with the occupants as the optimum amount of time they could endure the disruption.

But that was not the only innovative part of the project.

Rather than the client assuming the risk, contracts were established that made the delivery consortium partners jointly responsible for both schedule and the final energy efficiency of the properties. This strategy ensured that everyone had to buy-in to the concept.

Assembly line delivers on time

The work programme was designed like a ‘static’ car assembly line, as Rovers describes it:

“The workers move past the houses, performing their particular job case by case. The whole train of activities moves one house a day, so at any moment you can see all stages of the process simultaneously.”

Every aspect of the work plan was scrutinized and tweaked, including the workload of operatives (both on site and in the prefab factory), which were planned meticulously to ensure that each worker had a full day’s work.

Rovers reports that things did not go quite according to plan to begin with, because there were various teething problems, relating to late deliveries, organization of the site and working as a team, but by the time the tenth house had been completed, the ‘train’ was up to speed and the projected 10 days per house target was achieved.

In order to achieve this very impressive rate of working, a number of innovations were required:

  • Scaffolding was built in standard house-high elements, so that it could be moved by crane from a finished house to the next in line in just three steps;
  • Effort centred on renovating the facades, the roof and internal building services;
  • New, prefabricated roof elements were installed over the old roof finishes, which means that only some of the existing roof tiles had to be removed, increasing the level of insulation without damaging internal finishes;
  • Replacing the building services with a small boiler, a storage tank for the solar collector heat, a photovoltaic (PV) inverter system and a ventilation heat exchanger, had the added advantage of needing just eight connections to the exterior instead of the previous 28;
  • No electricity-saving measures were introduced: the PV roof is expected to produce around 2800 kWh per house and this, coupled with a vigorous efficiency campaign, could lead to a zero balance for electricity.

Full details of what it took to make the train run smoothly are given in Rovers’ paper, ‘New energy retrofit concept: “renovation trains” for mass housing’ (BRI, vol. 42, no. 6externallink 2014). Moreover, he also reports on the very positive feedback from occupants, and further innovations that are planned for the next phase of implementation – from 100 to 10,000 renovations a year. (See also, a time-lapse video of the work (item no. 5) and before-and-after photographs of the houses which are not unlike many in the UK externallink.)

Scaling up the train

Monitoring is ongoing at the Kerkrade project.

“Although the data have not yet been published by the housing corporation, the impression is that the performance is very good, when speaking with some inhabitants,” says Ronald Rovers.

Furthermore, Hestia’s project leader reported that the experience gained on this pilot project means that future retrofit trains could be at least 20% cheaper.

Other corporations in the Netherlands are getting onboard the retrofit train concept – Rovers is currently working for the provincial government to develop a regional plan for 10,000 housing retrofits a year – and if things go to plan this model could deliver 100,000 zero carbon houses by 2020.

Could it work in the UK, where onsite work is notoriously riddled with delays; not least from our unpredictable weather?

“The main speed-limiting circumstance was the wind: the cranes can’t work above a certain wind speed. The rain can of course be a problem, but we get our portion as well,” says Rovers. “The pilot project ran all year, though in two separate periods. But there was no specific weather planning.”

Indeed, a second project, by the Wonen Limburg housing corporation has pioneered another innovation that not only further speeded up the process, but also reduced the risk of wind by minimizing reliance on scaffolding. Their idea is so simple, it is surprising that it hasn’t been around for a long time: instead of installing the new building services in the loft, they are attached to the house as a separate unit, directly feeding into the prefabricated facade panels. This further avoids work inside the inhabited house, saves in cost and time and – though this is not explicitly mentioned in Rovers’ report – could have numerous benefits for future maintenance and upgrades (due to ease of access for trades).

When probed further on this aspect, Rovers says:

“Yes, it’s amazing it hasn’t been practised before. But I suppose it has grown that way: the heating in the form of a stove was always inside traditionally.

“Its specifically when retrofitting in an absurdly short time, with as little interference as possible with the inhabitants, that this works out well and can pave the way for more broad application. So far, no real technical problems have been observed, it has sparked further innovation and the latest pilot series show even much smaller units, consuming less space.”

... would the retrofit train pioneered in the Netherlands be a tempting model for the UK to follow?

Can the UK avoid hitting the buffers?

The UKGBC took its campaign for 1 million deep retrofits each year by 2020 to the party conferences this year, but although both Labour and the Liberal Democrats announced that they would recognise energy efficiency as an infrastructure priority in the next parliament, neither committed to allocating capital investment to energy efficiency or to adopt the target of 1m retrofits a year by 2020, says Richard Twinn, Policy and Public Affairs Officer at the UKGBC.

Since then, the organization has concentrated on making their economic arguments heard, particularly promoting studies by Cambridge Econometrics for the Energy Bill Revolution externallink which demonstrate that a national investment programme could pay for itself in 15 years, with every £1 invested by government increasing GDP by £3.20 and returning £1.27 back to the Treasury in taxation.

With that in mind, would the retrofit train pioneered in the Netherlands be a tempting model for the UK to follow?

“The initial costs per property may mean that it is not initially viable to many UK registered social landlords, but economies of scale could well see this decrease,” says Twinn. “There are probably questions as well about the applicability of the measures used to the UK’s housing stock, with our large number of older, hard to treat homes.

“But I think what this shows more than anything is that there is still huge potential for innovation in the retrofit industry. If the Government is willing to get behind a national programme and invest, then I’m sure we would see similar pilot schemes popping up in the UK.”

The problem is, of course, that most national politicians are reluctant to be make additional spending commitments in the run-up to a general election, to avoid looking profligate.

But wouldn’t it be great if – just for a change – politicians thought less of their own jobs and more about the long-term benefits to public finances, the economy and the climate? We can all dream!