Wed 2 Jan 2008
Learning from commercial construction
It goes without saying that building sustainable homes comes at a price. Roger Hunt takes some advice from the commercial sector on how to keep standards high and costs down.According to popular mythology Teflon and Velcro were products of the space program. In fact neither was developed specifically for this purpose, although WD-40, the ubiquitous lubricant, was; it proved invaluable in protecting the outer skin of the Atlas missile from rust and corrosion.
Within the construction industry, the path products and techniques take to market is equally mixed up in our perceptions with many benefiting from input from both the residential and commercial sectors. One of the reasons for this is that, while housebuilding has a need for a product, commercial construction often has the ability to develop it because it generally benefits from a greater availability of time, money and expertise.
This point is clearly made by the architect Bill Dunster who, in 1998, founded The ZEDfactory, a practice specialising in zero-carbon design and development.
"Commercial construction tends to have an architect, be more considered, to have less opinionated people controlling the design quality, to have bigger budgets and access to more engineering consultancy."
It is also worth remembering that the commercial sector is, by nature, innovative with companies wanting to show that they are embracing the future and a commitment to corporate social responsibility. Through their buildings they are seeking to demonstrate how they are optimistic about the future, says Dunster.
He explains that he spent the first 25 years of his architectural career designing very low carbon office buildings. "We used the best engineers, the best analytical techniques, we won lots of European Union grants, we tested lots of kit all over Europe and then we moved all that thinking straight into housing when we did the BedZED project."
At Make architects, partner Sean Affleck also points to the fact that, since commercial development takes much longer, there is time to investigate and improve the way systems can be utilised; citing as an example borehole cooling.
"Borehole cooling has been around for an awfully long time and has been used on commercial buildings in London for twenty odd years. Now, because of Part L and Ken Livingston in particular, more and more people are doing it and it is becoming much more affordable and you can bring borehole cooling into the housing market as well. It was developed for commercial because they had the money, technology and time to develop and tune the system."
Affleck is of the opinion that housebuilders would really be helped if they employed services and sustainability engineers for strategic advice, due to the depth of knowledge they can bring to a project.
One of the Make schemes which he uses to illustrate his thinking is the St Paul's Information Kiosk in London. "It is to the scale of a house so, at the beginning, we very much approached it as a house. We looked at boilers and the house systems but we found that in energy efficiency terms it wasn't very good so we started tapping into to the commercial sector and, initially, our QS said 'You can't afford this'. What is really fascinating is that you can."
The St Paul's Information Kiosk provides 140 square metres of internal accommodation and, having been engineered to exceed current Part L targets for CO2 emissions by 20 per cent, meets exacting environmental standards. The structure's envelope is insulated with natural wool while the interior environment is regulated using borehole cooling. In addition, a rainwater collection system provides all the building's flushing.
"That technology is affordable, is perfectly appropriate for housing and now is the time to grab it," emphasises Affleck.
It is not just information kiosks or smart headquarters buildings where sustainability is an issue. ProLogis is the world's largest owner, manager and developer of distribution facilities for customers that include manufacturers, retailers, and transportation companies. Its philosophy is to ensure the energy efficiency of its buildings is very high.
"Our buildings are massively airtight," says Ken Hall, ProLogis' managing director global development. "I think we've led the way in the industrial sector because of the scale of the problem. If you talk to most design and build house people, airtightness wouldn't be high on their agenda - but you find these same people spend a totally disproportionate amount of money putting photo voltaics on the roof while the building is still leaking."
As long-term building owners, ProLogis saw that carbon neutrality and low carbon buildings were going to be high value assets which undoubtedly made good commercial sense with retailers such as Sainsbury's and Marks & Spencer keen to set out their green credentials.
"We are a big provider to all of those retailers and now you can't even talk to them unless you can talk about superb, energy efficient carbon negative buildings; it is not in their imagination to rent anything else," says Hall.
While ProLogis invariably uses off-site construction methods, brewer Adnams opted for a new masonry system developed by Lime Technology to build its 4,400-square-metre logistics centre just outside Southwold in Suffolk.
For the Adnams project, Lime Technology provided unfired Sumatec compressed lime and earth blocks to create a diaphragm wall. In between the internal and external blockwork, Tradical Hemcrete was applied as an infill. As well as helping to lock up CO2 emissions this method has provided the building's necessary insulation.
Produced mainly from renewable resources, Tradical Hemcrete is a cast in situ hemp-lime walling. To take the product to its ultimate level, Lime Technology has since developed a zero carbon Hemcrete structural block.
The Adnams building also features a green sedum roof; clerestory glazing provides natural light to the interior; solar collectors heat the site's water while rainwater harvesting and foul water waste systems, including septic tank and reed beds, enable water to be cleaned and delivered to adjacent ponds.
With mixed use developments now common, housebuilders are increasingly involved with commercial projects. This is the case with Time & Tide; primarily known as a residential developer, it has recently begun moving into the commercial sector and is about to launch a dedicated commercial division. At The Green, part of the regeneration of Halton Mills, a brownfield site just outside Lancaster, it is creating a 4,645-square-metre eco-friendly office complex for up to 62 businesses.
Although there are inevitably lessons to be learned from the commercial sector, John Asplin, Time & Tide's managing director, believes that it is important to remember that residential developments operate in a very different market.
"Our experience in translating innovations from the commercial to the residential sector hinges not on possibility but viability. I think we're at a stage in the residential market where the end user's desire for sustainable homes is still quite a way ahead of their willingness to pay for them.
"In the commercial sector you are normally dealing with a single property, a more standardised architecture and a single-phase build, making the economies of scale much easier to achieve. Furthermore, any premium that still has to be passed on to the end user can often be incorporated into a service charge - something that they are already accustomed to paying."
It is not just developers that span both the residential and commercial sectors, many suppliers do. Heat pumps have been used in large scale applications in commercial establishments in Europe for many years and, through these installations, high output, high efficiency models have evolved.
Dimplex, for example, offers a new range of ground source heat pumps with outputs up to 130kW and high temperature models, with water temperatures of up to 70¡C, used for water heating. These are beginning to be considered as a viable solution for multiple dwelling buildings such as apartment blocks, using a large heat pump as a central heat generator, providing space heating via an underfloor system in each flat.
Solarcentury is another company to offer energy solutions both to housebuilders and commercial developers. At Manchester College of Arts and Technology, it has helped incorporate the latest solar technology into the new sixth form centre and library building.
The south facade has a striking monolithic array of solar PV modules integrated into the ventilated rainscreen cladding system, offsetting the building material costs of traditional cladding. The positioning of the solar modules in relation to the main wall and the creation of a 'cladding void' helps to regulate the internal temperatures of the building by minimising solar gain in the summer and, by encouraging a 'thermal stack effect', helps draw air through the building spaces.
While product innovation such as this will inevitably be crucial in the drive to build more sustainable homes, it cannot be seen in isolation. Time & Tide's John Asplin, believes "It's equally important that we educate the market to understand that, despite developers' willingness to absorb some cost, this sort of progression can only come at a price."
First published in Show House Magazine January 2008.
The greatest care has been taken to ensure accuracy but some information contained within this article may have changed since it was first published.
Posted by Roger Hunt
in Dimplex, Lime Technology, Make, ProLogis, Solarcentury, Sustainability, ZEDfactory on Wed 2 Jan 2008
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