Positive mental attitude


The multi-award winning Springfield Meadows is a collection of 25 ‘carbon positive’ homes in Oxfordshire, designed by Greencore Construction to be the UK’s ‘most sustainable development.’ MD Ian Pritchett tells Jack Wooler how the project was a victory over continual planning obstacles

Zero-embodied carbon; net-zero energy in use; climate positive; ‘One Planet Living Global Leadership’; partnership with BBO Wildlife Trust; all electric-development – when it comes to sustainability, Springfield Meadows is the ‘full monty.’

Designed, manufactured and built by Greencore in their offsite factory, the company says its lime-hemp insulated timber frame system allowed the 25-home development in Southmoor, Oxfordshire, to be developed to deliver Passivhaus standards at a similar price point to traditional housing, creating what has been labelled “the most sustainable development in the country.”

In the past year, the scheme – offering both social housing and private custom-builds – has received the appropriate praise for such an achievement from all sides of the housing industry, from OxProp’s ‘Best Residential Housing Development,’ the Structural Timber Awards ‘Timber Framed Project of the Year’, to Bioregional’s ‘One Planet Living Global Leader’ award, and more.

Despite all the plaudits, Ian Pritchett, managing director of Greencore, tells me that the UK planning system has hampered the project at every turn, losing the company time and money. It even required some elements of the project to be built before full permission was assented, as local dignitaries and national TV stations publicised the project’s groundbreaking design as ‘the future of housing in the UK.’

As such, the project is both a testament to the way green building can be done in the UK, and a clear display of how the systems behind housing delivery have not yet caught up with the Government’s intended aims of decarbonisation.

Walking down the narrow lane to the site, the development’s low density is immediately obvious – in fact it’s around a third of the typical housing density in the UK, according to its developers, with nine affordable units and 16 open market homes spread across seven acres.

This lane caused one of the earliest setbacks introduced by the planners; its small size caused them to reject any more plots being introduced onto the site. Now, including private plots ranging from a tenth to a half of an acre, the scheme features some very desirable, custom-built homes of around 100 to 300 m2 of GIA (Gross Internal Area). The level of luxury was needed to ensure the private homes in particular were economically viable, the social portion comprising nine homes being sold as a whole to housing association Sovereign.

Green groundwork
Alongside the sheer size of the homes, another benefit of its low density was in enabling the road and infrastructure to be designed around the existing trees, including a large oak tree at the centre of the site. The road winds its way around, giving the development a distinctive, curving shape.

The impact of the development was further eased by its unobtrusive, all-electric nature – removing the need for gas works. The SuDS installation, instigated at an early stage, sits under the road, avoiding unnecessary additional groundwork.

Another ‘nature-first’ aspect of the scheme was hedge planting around what is already a particularly green site area hosting native English species. They have been chosen to benefit biodiversity, extending the season for flowers, and producing higher levels of nectars and berries to help wildlife. This effort has been supported and aided significantly by what Greencore claims is the first partnership between a developer and the Wildlife Trust.

Natural verticality
Looking at the houses themselves, the buildings proudly display their use of natural materials, clad in various timber species, including brimstone poplar as well as Siberian and English Larch, but also Kebony ‘modified wood’ cladding.

Pritchett says there was a “very deliberate” decision to mix up the “architectural journey of the site” with different forms. Most of the homes have steeply pitched roofs throughout at 50˚, and a few have pitched roofs plus garages with flat roofs, and at the end of the site there are four large, flat-roofed, contemporary villas.

Where the roofs are pitched, they are generally terracotta coloured clay tiles, but where buyers have requested different options (on the custom built homes) – there are variations, such as one grey clay tiled house.

One thing that remains the same across all the roofs however are the extensive solar PV arrays, integrated onto the roofing rather than sitting on top of it, something which allows producing a “less jarring” design than former iterations, says Pritchett.

Much like the majority of the roofs on the development, the homes’ design gives them what Pritchett describes as a “certain verticality” – the team have employed taller, narrower windows than normal – “ending up with an architecture based on portrait rather than landscape.” This is continued in the cladding strips, which are arranged vertically.

Passivhaus principles
Entering the homes, the ground floors are in the main ceramic tiles plus underfloor heating. Oak staircases and joinery help to provide a contemporary, while natural feel to the interior design. Floors above rest on a cross-laminated timber base, which helped make the second phase of the project ‘carbon positive,’ as a result of sequestering significant amounts of carbon within the structure.

In terms of heating, for an all-electric development there are relatively few heat pumps installed – only where custom-build clients have requested them. In general, the homes use direct electric heating and hot water. This is fed directly from the solar arrays on the roof, using any electricity they create in the first instance – before importing it from the grid.

Many of the homes also have batteries installed, meaning that if they aren’t using all the electricity the panels produce. The battery can be charged for later use, and then the surplus imported back to the grid – for which the grid will pay a small fee to the homeowner.

When it comes to daylighting, Greencore “followed the principles of Passivhaus,” as on all other aspects of the properties – from the high levels of insulation, the triple-glazed windows, high levels of air tightness, and of course, solar orientation.

“Sadly,” he says, however, the UK planning system makes optimum solar orientation “very difficult,” being “far more concerned with following building lines and convention than optimisation.” As such, the design team “did the best they could” to introduce the maximum natural light through orientation, but in the end decided to spend more money on the PVs to compensate for any deficits in solar gain.

Beyond expectations
All of the homes – as all that Greencore builds – have been constructed using the company’s ‘Biond’ building system.

Developed in-house eight years ago, Biond (a play on words combining ‘performing beyond expectations,’ and ‘bio-based’), is a hemp-lime panelised construction system. Pritchett says it’s more flexible than volumetric methods, avoids “copy and paste-looking houses,” and allows the team to deliver higher quality and accuracy of measurement, while avoiding thermal bridging, and minimising any construction shortcomings when compared with generic building methods.

The system employs the natural ‘phase change’ properties of hemp used to perform “much better than its U-values suggest.” The MD adds: “It allows us to build zero carbon houses at the same rate and cost that other people build traditional, Building Regs-compliant homes.

He asserts: “We think it’s the best building system out there, that’s why we’re not prepared to build with anything else!”

Tackling the real challenge
Despite the impressive performance credentials and innovative build methods behind the new homes, Pritchett tells me that the “construction was the easy part.”

“We can do zero carbon houses like shelling peas now; we’ve built about 60 over the last five years, so we know what works and what doesn’t,” he says. “Finding the site, getting the funding, putting it all together – that’s where the real challenge lies.”

Market conditions were one such hold up for the company, heavily affecting cash flow and sales: “The country was just in the process of leaving the EU during the development process, and we were supposed to ‘get Brexit done’ by March 2019, but that didn’t happen, and it proved difficult to make sales in that market, and indeed for the rest of the year.”

After the market returned to some normality (Pritchett says that the General Election producing a majority Government was beneficial to market stability), in January and February 2020 it “proved really buoyant.” However then Covid hit, and lockdown brought “yet more delays, uncertainty, and challenges to the process.”

He decries the planning system as a “great burden” to projects, and one which he has struggled with throughout not just this project, but “in his whole career.”

“We come across it all the time,” he explains. “The system is policed very rigidly and vigorously, but it’s a 10 year old policy, it’s too focused on garden sizes, parking, numbers of bedrooms, and not on carbon, energy and ecology, the things we need to be addressing.”

“It’s just not in line with delivering zero carbon for 2050,” he adds.

Despite the challenges, the planning officers had been “pretty positive” all the way through the process, says Pritchett. He however believes that this was a double-edged sword; because the “planners liked the scheme so much,” they imposed various conditions that they perhaps wouldn’t have if it were a “lesser scheme.”

“Because it was such a high quality eco-scheme, they were very strict with us, causing a lot of frustration,” Pritchett continues. “First, they took away our permitted development rights – which nearly lost us sales – and then they began drilling down into a lot more of the design than is typical.”

The MD believes this pressure caused the team to rush through the planning process in order to meet the unexpected extra demands. As a result of this, he says, there were some missing elements of the project in the early design that needed amending; mostly small changes such as slight window repositioning. One large omission however, was that the solar panels to be installed on the roofs hadn’t been explicitly shown at the reserved matters application stage.

Greencore put in an application for ‘non-material amendments’ to fix these issues, which, at first, the planners agreed to. After eight weeks through the process, however, “when they were just about to approve it,” says Pritchett, “they suddenly pulled the rug out from under our feet and said – ‘the key effect of the changes is material, and therefore you’ve got to withdraw this application and submit it as an Action 73 Application.’”

“We wasted two months in that process,” he complains, “and then we spent another 13 trying to get the Section 73 approved.”

This produced a sequence of bizarre scenarios, where “busloads of councils, local MPs, reporters and more were coming round to say, ‘this is the way to build houses going forward,’” and all the while the team was installing the solar panels that were being celebrated – without yet having permission.

“It was a nightmare, we nearly lost the sale of all the affordable houses to this,” he adds. “It was a great example of how the planning process is not fit for delivering eco houses for the future – it’s really set up for delivering more of the same rather than something different.”

Time for change
Moving forward, Pritchett is glad that the project has been so well regarded, but he argues that, if the country is to meet its 2050 Carbon targets, there has got to be “serious movement in policy.”

As well as removing some of the planning barriers the company has faced at Springfield Meadows, he argues that there should in fact be financial incentives for building better.

He suggests, for example, that the Community Infrastructure Levy should be variable, with cost savings for building above the Building Regulations in terms of sustainability.

As an example of success in the past here, he notes the “generous” early subsidies for solar panels, and the “highly lucrative” feed-in tariffs at its inception, which once paid significantly more than at present for any remaining electricity from solar panels sent back to the grid.

“The policies around PVs have shown that, within a 10 year period of growth in the market – during which we saw massive uptake and vastly reduced manufacturing and installation costs – you no longer need huge subsidies.”

Whatever the Government does next, however, Pritchett is proud to have “set an example of how development could be done in the future.”

“There are still three million new houses planned by the Government over the next 10-15 years,” he says. “If everything was built using a system like ours, you’d save about 600 million tonnes of CO2 emissions – on the pathway to zero carbon by 2050, big numbers like that can’t be ignored.”