Chalk and cheese are words that spring to mind comparing a Potton timber frame or post and beam house with Kingspan Off-Site’s Lighthouse experimental ‘eco-home’.
Potton, which serves the developer market but has become best known as a self-build timber frame provider, has some customers who like a modern design twist. But most tend to more traditional styling, hence such range names in its brochure as Rectory and Heritage.
By contrast, the Lighthouse, built at the BRE’s Innovation Park, is real shock of the new stuff. Constructed from Kingspan’s TEK structural insulated panels (SIPs) and glulam, it resembles an upended boat, clad ground to gable in sweet chestnut, with its arcing timber roof festooned in PV and solar thermal panels.
According to Kingspan’s technical director Dr Paul Newman, Lighthouse deliberately pushed aesthetic boundaries to underline its cutting-edge environmental performance – and it was the first house to achieve the top level 6 of the government’s Code for Sustainable Homes (CSH). But some of the real-life commercial and social housing developments the company has worked on have also worn their green hearts on their sleeves and been unashamedly contemporary, and that’s clearly set to continue. Take the striking modular HOUSE developed by Kingspan with partner architect Richard Pain which showcased at Ecobuild this year. The geometric SIPs design enables units to stand alone, or slot together like strangely shaped play bricks – an impression reinforced by the wooden blocks Pain used to demonstrate this capability.
Against this backdrop, the official announcement at Ecobuild of the marriage of these two operations to form Kingspan Potton (KP), a single timber-based construction business ranging from upmarket self-build, to mass-market social housing, inevitably caused a stir.
Potton has been part of the Kingspan Group for several years, alongside its insulation-manufacturing arm, renewables technology and steel-frame building divisions, the TEK SIPs factory in Germany and, of course, Kingspan Off-Site. Until now, though, it’s operated quite separately.
Low energy, low carbon building
However, KP commercial and sales director Tony Hutchison insists the merged “retail and volume facing” operation makes sense. Scratch the surface of the two sides of the business and their respective customer bases and there are shared aims and opportunities for synergy and knowledge sharing. “The companies had different areas of expertise,” he said. “But they’re complementary and both are focused on low energy, low carbon building.”
“Technically precise, quality, sustainable solutions are goals across the whole business,” agreed Newman. And so too, he might have added, are drawing on the lessons of Lighthouse to drive take-up of offsite prefabrication, help customers attain higher levels of the CSH and introduce them to new technologies and products, from engineered wood, to renewables.
The company acknowledges that most self-build customers remain design conservatives, whether opting for its designs, or using their own architect. But beneath the skins of their houses, it maintains, they’re increasingly leaning towards higher tech materials and modern methods of construction (MMC).
“A big shift has been in the use of factory-fitted insulation,” said business services director Alasdair Dando. “We didn’t do it at all a few years back; now it’s specified for 90% of self-build.”
“And the uniformity and quality of the timber frame panels this delivers means better, more consistent
airtightness,” said Newman.
In addition, self-builders are being won over to a modern engineered version of timber floor and ceiling joists, the MiTek Posi-Joist, comprising timber flanges and a steel strut web. “When self-builders visiting the factory see the Posi-Joist, they want it,” said production and site operations director Doug Bircham. “As a result, we’re now installing another press to fabricate them.”
“They particularly appeal to self-builders who want hands-on involvement because they’re so light and easy to manhandle,” said Newman. “They also make it straightforward to accommodate services and network your home. Everything just threads through the web.”
However much their house resembles a Victorian rectory, self-builders are also among the most committed on
environmental performance and increasingly keen on renewables. “Solar thermal is the most popular technology, but there’s a growing market for ground and air source heat pumps and the feed-in tariff is driving interest in PV,” said Newman.
Having a sister renewables division, he added, KP can supply the technology itself, or “advice and pointers.” It can also hand-hold self-builders through the CSH. “They can find the process intimidating, but we now offer the services of our own Code assessors and, based on our work on the Lighthouse, we’ve also launched a CSH compliance assurance scheme, ” said Newman. “And we find most self builders go for level 3.”
CSH services
The company is developing a following for its new CSH services in its volume businesses too, and here the focus on helping customers crack the Code has also led to another departure: the Vantage range of “pre-engineered, pre-coded” affordable homes. Available as timber frame, but expected to use mainly TEK SIPs, these have essentially been designed around the CSH by partner architects Richard Pike Associates and Aus-Haus. Style-wise they cover the gamut from the relatively conventional to designs as overtly ‘eco-home’ as Pain’s HOUSE.
“Vantage is the key outcome so far of the Lighthouse project,” said Hutchison. “The lessons we learned enable us to deliver a platform where developers don’t have to worry about the CSH, but at the same time it‘s flexible, giving them over 30 different footprints and free reign on façade and finish.”
“It’s real plug and play housing,” said Newman.
KP backs the UK Timber Frame Association’s “fabric first” campaign, urging developers to attain as high a CSH level as possible with the building envelope, before installing renewables. But, once more drawing on the Lighthouse experiment, it believes this still can’t get builders above level 4 on a consistent commercial scale (Vantage houses are marketed at levels 3 or 4). “Achieving level 4 with the fabric is our aim as standard, but it’s still a challenge – it doesn’t just happen,” said Newman.
Reaching levels 5 and 6, in his view, does not require the level of eco hardware used in the Lighthouse, which “you need a PhD to operate”, but it does demand a renewables package of some sort. In the “large number” of level 5 developments the company has supplied to date, the most popular technologies have been mechanical ventilation with heat recovery (MVHR), solar thermal and, increasingly, PVs.
Hanham Hall
According to Newman, the project KP is working on which best illustrates how to achieve CSH level 6 is Barratt’s 200-home Hanham Hall private/affordable housing development near Bristol, the first English Partnerships’ Carbon Challenge winner.
“This is very exciting – the first mass attempt to achieve level 6,” he said. “The houses, designed by HTA
Architects, use TEK SIPs to achieve an airtight, thermally-efficient envelope, and MVHR and ‘thermowood’ shutters to help manage the internal environment. But the key is the operation of the community as a sustainable whole. This includes having a central biomass-fuelled heat and power plant, so everything comes through the wall, really simplifying occupancy and taking away the need for residents to manage each building.” KP’s work on the site, he added, starts this year.
Meanwhile, back at the factory in Bedfordshire, housing components for its various markets sit comfortably side by side. Post and beam production may require particular skills – with customers, for instance, offered various levels of age distressing on their Douglas fir beams – but, according to Doug Bircham, the workforce elsewhere switches readily between different products, materials and systems, one week working on timber frame panels for self-build, the next SIPs for volume customers.
Currently the plant produces more for the latter, with self-build hit harder by the downturn, but ultimately the aim is a 50/50 split. And evidence of the confidence in the long-term prospects of the KP marriage is a large area of
concrete slab just laid for expansion.
There are also early signs of further potential for product and design cross-fertilisation across the business. About 10% of its self-builders are now opting for TEK SIPs and it also now has an off-the-peg SIPs range for the market. Zenit is not the Lighthouse, but with its monopitch roofs and render and timber-clad finish, the comparison is not a case of chalk and cheese either.
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Self-builders tend to favour traditional designs, but they are also among the most committed to environmental performance |
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Building with structural insulated panels (SIPs) |
