Until now existing buildings have been conveniently overlooked in the pursuit of sexy zero carbon new-build. But it looks like all that is about to change.
Let’s face it: Refurbishment isn’t sexy. Building ultra-sustainable office buildings with wind turbines sprouting from the roof is much more likely to get political and architectural juices flowing.
So it’s hardly surprising that minds have been concentrated on how to make new buildings more energy efficient, conveniently ignoring the fact that the vast majority of our building stock has been around for decades, if not centuries.
In the past 12 to 18 months, however, there’s been a shift in attitude. Now there are examples of energy efficient refurbishments starting to creep into the eco-picture as the case studies below demonstrate. And last month the first parliamentary inquiry into the greening of existing commercial stock was launched by the All Party Urban Development Group.
The commercial sector is moving faster than the domestic one, as a number of factors come into play. Building owners are realising that the issue is here to stay, underlined by the introduction of Energy Performance Certificates in line with the EU directive, and the government’s setting of ambitious carbon reduction targets.
There’s also the financial angle. Older buildings may become obsolete more quickly if their newer competitors are more energy efficient. And the current uncertain economic climate could exacerbate the problem. ‘Lately the credit crunch has raised the issue of how to differentiate your properties, giving more value to high-end properties of which sustainability is a part,’ says Tatiana Bosteels, climate change manager at the London Climate Change Agency.
Bosteels is project managing a new partnership of large property companies who aim to share information to define what value can be added to a property by making it more sustainable.
At the moment the answer is none: the main barrier to upgrading stock being cost. Industry representatives appearing before the parliamentary inquiry are likely to call for fiscal incentives such as zero VAT on work that reduces the carbon output of a building.
Housing is an even tougher nut to crack. Here again, the main barrier is cost, not least because the majority of homes are privately owned. Homebuyers can find out how energy efficient their homes are now thanks to the introduction of Energy Performance Certificates last year, but does anyone really care? Reductions in stamp duty or council tax have been suggested as possible encouragement to make improvements.
Greg Slater, an associate at PRP Architects, also points to the lack of standards. While commercial buildings have BREEAM, which can be applied to refurbishments, the Code for Sustainable Homes only applies to new build.
Technology is also lacking. A large percentage of the least efficient housing was built pre-1920s which means they have no wall cavities to fill with insulation. And slapping insulating boards on internal walls or overcladding externally can cover period features and destroy the house’s character.
‘We urgently need product development in the refurbishment sector including further advancement in thin, high-performance insulated linings,’ says Slater.
So there are still plenty of barriers to overcome if the issue of our energy inefficient existing stock is to be tackled en masse.
But as the examples below show, it can be done.
Setting new standards
Transformation of disused Victorian Stable Block buildings, BRE Innovation Park in Watford
Solid brick walls, a clay tile roof, dampness, asbestos, sash windows, poor thermal performance, disrepair and resident bats. The challenges faced by the team converting this disused 1855 Victorian building, called the Stable Block, into three energy efficient homes are common to much older housing stock.
The project is one of 10 being carried out by the BRE’s rethinking housing refurbishment team in partnership with the Housing Market Renewal Pathfinders and The Prince’s Foundation for the Built Environment, and includes terraced houses and Victorian villas. Data from each will be used to create tools and guidance for use on different housing types and budgets.
Improvements to the Stable Block’s building fabric are currently under way and include internal dry lining of external walls with insulation and composite board, high-performance insulation in the roof spaces and secondary glazing to draught-proof windows.
Installed sustainable technologies will include biomass boilers, solar thermal panels, low energy lighting and heat recovery ventilation.
When the refurbishment is completed in September 2009, BRE will test for moisture, airtightness, humidity, sound insulation, air quality, water consumption, resource efficiency and thermal performance. Combined with measurements taken before work began, the data will inform the development of new guidance and tools to help the industry improve standards nationally. A regeneration cost modelling tool is also being developed to help owners decide between demolishing or refurbishment options.
‘Many older homes have poor energy ratings. This project will set standards in key areas – sustainability, occupant needs, insulation, renewables, materials and maintenance,’ said David Housego from the BRE team.
Watch out for the following reports: Best Practice Guide to Green Refurbishment; Technical Report; Finance Report; Regeneration Model (demolish or refurbish decision making tool); and the Natural England Environment Report.
A refurb for the masses
Ecoterrace, Newcastle-under-Lyme
It may only be six small Victorian terraced houses in Newcastle-under-Lyme but the Ecoterrace project has some pretty big ambitions. The principles behind the refurbishment are to deliver energy efficient upgrades which any homeowner could implement, whilst enhancing the property’s market value and the occupiers’ quality of life.
‘This blinkered focus on zero carbon conditions is not what it’s all about,’ says Rob Annable a director of Axis Design Architects who, with his colleague Mike Menzies, is responsible for the design. ‘We are seeing a lot of discussions about reducing carbon output but not about improving the living quality of some of these houses.’
Axis, working with Staffordshire Housing Association, won a competition to refurb the properties last summer. The clients – Newcastle-under-Lyme Borough Council and Renew North Staffordshire funded by the Housing Corporation – wanted to demonstrate that major refurbishment rather than demolition and new-build could be a viable option for renewing ageing housing stock.
Axis’s plan was to establish some generic design principles which could be applied to any Victorian terrace. It came up with two main ideas.
First, the services should be positioned centrally within the house. This means that whether the main drains are located at the front or back of the property, the distance is the same. And, explains Annable, it leaves all habitable rooms with windows. However, this also requires the downstairs toilet and upstairs bathroom to be ventilated. Axis is trialling different ventilation systems to find out which is more effective and the properties will be monitored by Hockerton Housing Project once inhabited.
Second, Axis decided to demolish where possible the single-storey leg at the rear – a feature of many Victorian properties which usually contains a kitchen and downstairs bathroom – and to add a triangular ‘sun space’. The angled walls allow it to be aligned to get the best solar gains possible without encroaching on party walls. Annable explains that this is not a perfect sun space since it cannot be divided off from the main house, ‘but it does make for a beautiful lounge and bedroom’.
Insulation, of course, has been added: 80mm-thick drylining internally on the walls and the whole of the floor has been dug out and insulation installed. Insulation has also been added to the roof.
The first two of the six properties, which have been refurbished first as they will become affordable housing, make use of an air-to-air heat exchanger on the roof – the Nuair Sun Wall – which can be used for heating, cooling or warming water and which ventilates the bathrooms.
The heating specification might be a bit belt and braces, admits Annable, since he has included a conventional high-efficiency boiler and radiators together with the Nuair system. But he still reckons the space heating bill will drop from £1,200 a year to £200.
But what about the big question: how much did it cost? The first two came in at £1,095/m2 excluding VAT and fees, which translates to £60,000-£70,000 per property.
This is comparable to new build, says Annable, who points out that a property owner could pick and choose from the improvements they make and do things incrementally.
Green upgrade for 15% more
Unit 4, Cambridge Business Park
Property owner the Crown Estate shelled out £1.5m on the refurbishment of this 20-year-old building on a Cambridge business park. Through the upgrade it achieved an ‘excellent’ BREEAM rating, which the company’s head of regional and residential Jim Yates estimates added between 10 and 15% to the cost of a standard refurb.
Yates lists three reasons for investing in energy efficiency: the company’s two-year-old strategy to get the best environmental performance possible from a building; to future-proof the building since The Crown Estate is a long-term investor; and the market in Cambridge is becoming well-tuned to the issue.
Many of the changes would have happened in any refurbishment: new M&E; new cladding, including more windows to bring in natural light; new ceilings and floors. The ‘extras’ which helped gain the excellent BREEAM rating included rainwater harvesting, leak detection, low-energy lighting and cycle storage. Contractor Hutton Construction also had to do its bit with site and materials management.
In carbon emission terms the building boasts a 26% improvement on current Building Regulations standards and a 26% reduction in energy consumption, according to King Sturge partner Helen Gough who advised The Crown Estate on the refurbishment.
So does all this mean that tenants will pay more? ‘It’s very difficult to prove you are adding value,’ confesses Yates. ‘There is no evidence to prove that tenants will pay more rent.’ However, the leasehold was snapped up almost immediately. And if economic conditions worsen, letting property quickly becomes even more vital: ‘At the moment the market for letting space is very good, but we are very conscious that could change very quickly,’ says Yates.
Cheaper than new build
Hampshire County Council’s offices, Winchester
Hampshire County Council’s offices in Winchester could be considered a bit of a blot on the landscape: a typical lump of a 1960s office building set within the beautiful traditional surroundings of the cathedral city.
So when the council wanted new sustainable offices, the easiest solution would have been to decamp to a new site outside the city centre and start again. But architect Bennetts Associates suggested a revamp of the existing building and the council agreed.
It’s a pretty drastic refurbishment, involving stripping the old building back to its frame, but it has the advantages of preserving the council’s position in the city centre and avoiding staff relocation. The council also felt that since it had built the building in the 1960s, it was morally right that it should deal with the problem it had become.
But the best bit is that it is actually costing less. ‘The construction costs are pretty similar, but it’s quicker so the overall project costs are less than for a new build,’ says project architect Peter Fisher, an associate with Bennetts.
One of the biggest challenges was the ventilation. Fisher explains that the best daytime cooling comes from cross-ventilation – or having windows at both sides of the offices open. Unfortunately this wasn’t possible because to have windows open on the street side would have been too noisy. So Bennetts is adding brick-clad ventilation ducts on the street side of the building, with wind troughs on the roof to create negative pressure, which draw air across from open windows on the courtyard side of the building.
All the nasty concrete cladding has gone to be replaced by Velfac on three sides and a combination of Velfac and the brickwork on the street side. Internally the concrete frame has been exposed to make the most of the building’s thermal mass.
HBG started the project in summer 2006, with the first of four blocks completed at the end of 2007. The remaining two should be done by summer 2009 and the Carbon Trust, which carried out monitoring prior to the refurb, will be monitoring the new improved offices to provide some cold hard facts on the energy savings.
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Construction Manager
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