In this month's sustainable homes special, What's the Spec shows you how to harness the June sunshine to plan winter-warm homes, and insulate with recycled materials
Geothermal heating comes to London
The first four homes in the capital to have geothermal hot water and heating are being built in Norbury, south London. At the Earthdome development, a system of pipes will transfer heat from the relatively warm earth via a ground source heat pump. "The advantage of the system is that the heat in the ground is there 24 hours a day and 365 days a year," says developer Bob Harris, who recently received a Green Apple Environment Award. Ground source heat pumps don't take up any space in residents' homes. Harris says that if measured against an electric system the payback is two years. Compared to a gas system, the payback is said to be 12 years.
Ice Energy Heat Pumps 600

King's Cross estate gets solar power
A Peabody Trust estate in King's Cross has had 2000 m2 of Solar Century photo-voltaic roof tiles installed by contractor Richardson. The tiles will generate all the electric power required by the Priors Estate and provide a surplus to be fed into the national grid. To optimise solar gain, the estate buildings' flat roofs were converted to steel-framed monopitched roofs. Solar Century has also recently completed the first installation of its new C21 solar roof tile. The PV tile is designed to integrate aesthetically with conventional tiles. For most developments, Solar Century says that planning permission will not be required. The C21 tiles, which recently won the Best Exterior Product award at Interbuild, were used in six new homes in Lincolnshire by Gusto Construction.
Solar Century 601

Light pipes for standard roofs
Roofing provider Glidevale has launched Sunscoop, a tubular rooflight that can be fitted onto standard pitched or flat roofs. It uses a mirrored tube system to reflect natural daylight into a building's interior. Glidevale says the Sunscoop has a reflectivity of 95% and uses a deflector to "collect" light when the sun is low in the sky. It is available in 250 mm, 350 mm and 530 mm diameters with a wide range of roof flashing to ensure weathertight fitting. Glidevale also says that the double skin glazing also improves thermal performance and meets efficiency requirements laid out in Part L of the building regulations.
Glidevale 602

Sustainable primary school in Suffolk
HLD has supplied the timber for Beaumont Primary School (pictured above) in Hadleigh, Suffolk, which was constructed to promote environmentally conscious design and energy efficiency. The timber structure is insulated with recycled newspaper, has a sedum roof and is clad in untreated western red cedar. Other green features are solar panels, high level windows and a water filtration system that captures rainwater for flushing toilets.
HLD 603

Domestic log and pellet boilers
3G Energi is introducing domestic boiler systems that burn logs and wooden pellets into the UK. The boiler systems have outputs of 15 to 50 kW and come with compensating control packages and heat stores. 3G Energi says that the boilers are approved for assistance from the government's £10m Clear Skies grant programme for renewable energy installations. The systems have a microprocessor controller to keep homes at a constant temperature and can be adapted to use heat sources such as solar panels.
3G Energi 604

Sustainable prefabricated buildings
Kingspan Off-Site has teamed up with a number of UK off-site manufacturers to provide bespoke whole building packages. The company claims that the system can reduce M&E plant, energy operating costs and cut CO2 emissions by up to 40%. Additional partners can be included in the project to meet clients' requirements.

A Best Practice Design Guide has also been published to provide a range of interface details and specifications. The range will include a palette of wall, facade and roof systems, including various formats, colours, textures and material finishes. Factory installed M&E services developed by NG Bailey are also available. Kingspan Off-Site has developed a range of exemplar designs for keyworker/student and social housing with HLM Architects, Arup and Cyril Sweett. There are also designs for healthcare and education buildings.
Kingspan Off-Site 909

Ground source heat pumps
Penwith Housing Association has used ground source heat pumps (GSHPs) at four semi-detached bungalows in Marazion, Cornwall. The system provides space heating and, in some cases, pre-heating for hot water. A coil was laid in a shallow trench in the garden, and filled with a fluid that absorbs heat. The fluid then passes into the house and through a heat pump, which heats up hot water for the heating system. The Energy Savings Trust says that GSHPs are 300-400% more efficient than condensing boilers, which are themselves around 90% efficient. Each system costs £4500 and total heating and hot water bills are £100 a year.
Geoscience 910

Combined heat and power is academic
The University of Edinburgh is specifying a combined heat and power system for the Pollock Halls of Residence. The move follows the installation of a gas-fired CHP system at the University's King's Building Energy Centre. The Energy Saving Trust calculates that CHP can be 25-40% more energy efficient, as the waste heat is not dissipated. The electricity can be sold to customers of the scheme or back to the national grid. The University estimated that CHP has cut its annual carbon dioxide emissions by more than 2000 tonnes. Once it has repaid its investment, it expects to reduce running costs by around £400,000 a year. The Community Energy Programme run by the EST and Carbon Trust gave the University a grant of £1.63m towards the scheme.
CHP System: Jenbacher 911

Housing group moves to eco-friendly HQ
New Charter Housing Trust Group has moved its headquarters to a new environmentally friendly building in Ashton-under-Lyne, Greater Manchester. The 48,000 ft2 office is passively ventilated and boasts green features such as combined heat and power and greywater recycling. The Cavendish Street office is also positioned next to the proposed Metrolink extension from Manchester, which should encourage some of the 375 staff to leave their cars at home.
CHP: Bowman Power 913

Hybrid steel external wall system
Dryvit and Lindab have joined forces to develop a steel external wall system that they claim has the same thermal performance as timber. The system combines Dryvit's External Insulation and Finishing System (EIFS) and Lindab's Construline lightweight steel external wall studs system. Dryvit and Lindab says the combination of steel and insulated render has a back-to-back warranty covering both elements, and only needs one installer. EIFS consists of expanding polystyrene insulation boards protected by a glass fibre reinforcement mesh and finished with an acrylic render. Construline also eliminates the cold bridging normally associated with steel stud systems.
Lindab 914

Interlocking formwork concrete blocks
Styro Stones has introduced a new range of interlocking insulated concrete formwork blocks that can be used to construct buildings with U-values as low as 0.11 W/m2K. The Neopor range consists of two faces of Neopor, similar to polyester, which form a 150 mm cavity to be filled with poured concrete. The upper and lower edges of each Styro Stone block are castellated to allow a firm interlock with adjacent Styro Stones. Styro Stones claims that skilled tradesmen are not required for Neopor components. The first Neopor project in the UK is a barn extension now under way in Northumberland.
Styro Stones 915

Recycled carpet tiles
Obsolete carpet tiles from the Civil Aviation Authority's offices in London have been recycled by Interface under its ReEntry Scheme. Interface's Huega Festival carpet tiles covering a total area of 12,000 m2 were collected from the CAA and taken to a refurbishing plant in West Yorkshire where they were deep cleaned using a dry-powder system. The scheme is a partnership between Interface and not-for-profit company Pennine Magpie, which employs people with learning difficulties. Once cleaned, the tiles are sold to community groups and social enterprises.
Interface 916

Waste & Resources Action Programme
The Waste & Resources Action Programme (WRAP), the government agency promoting the use of reclaimed materials, has an online resource called AggRegain, which allows specifiers to select recycled and secondary aggregates from more than 250 suppliers.

In July a web-based procurement resource offer advice on sourcing recycled materials.
Wrap 917

Green building division
The Green Building Store has opened a division targeting the public and commercial building sectors. As well as showcasing its range of sustainable products, Less Is More offers a range of services to local authorities, housing associations and commercial clients. A separate area on the Green Building Store website provides technical guidance. Products in the Less Is More range include the Airflush Urinal System and Megrame timber and aluminium doors and windows.
Green Building Store 918

What’s the spec?

The Wintles, Bishops Castle, Shropshire
Living Villages, an eco-developer in Shropshire is building a 40-home development using mostly local materials. The 12 homes built so far at The Wintles in Bishops Castle include oak frames sourced locally and lime render and mortar from nearby Much Wenlock. “It’s not a regionalist thing,” says Andrew Mason of contractor Ecostruct. “We want to avoid long-distance deliveries and avoid embodied energy.” Local specification was not entirely possible though, according to Bob Tomlinson, director of Living Villages. For example, the triple-glazed timber windows had to be imported from Sweden. Tomlinson says British firms supplying sustainable products are often too small to deal with large sites. “We’ve found that the supply is not guaranteed enough for us. But we think that will improve.” The houses range in size from two to six bedrooms, and low-energy and sustainable features include triple-glazing, heat exchangers, and reclaimed bricks and tiles. The interior timber used for floors, architraves, skirting and kitchens are all sourced locally, as is the weatherboarding. The homes also use thermal mass to minimise temperature fluctuations. The reclaimed bricks, stones and rammed earth are arranged around wood-burners. When air temperatures fall at night, the heat retained in the thermal mass means that less energy will be required to reheat the rooms the next day. In the summer, the coolth retained by the thermal mass at night helps keep the rooms pleasantly chilled during the day, making fans unnecessary. Each home has hot water solar panels on the roof, which Tomlinson says provides 60% of the water heating. Photovoltaics were not viable though, according to Tomlinson, who was not tempted to apply for a DTI solar grant. “As it’s a commercial venture we have to do it without grants. We want to prove it can happen in the real world,” he says. The Living Villages Trust is a not-for-profit company, and Tomlinson says its remit is to encourage sustainable building. Developers may be encouraged by the fact that the homes are selling at a price 25-30% higher than a development on the other side of town. Developer/designer Living Villages
Contractor Ecostruct 01588 660123
  • Solar hot water panels
    Filsrol Solar 607
  • Terracotta chimney pots
    Red Bank Manufacturing 605
  • Reclaimed bricks and tiles
    Castle Reclaim

    01787 278669 606
  • Timber softwood
    Charles Ransford
    Pontrillas Timber
    01981-240444 608
  • Standing seam roofing halter

    Ash & Lacy has launched a new halter for its Ashzip Standing Seam Roofing System. The halter replaces the conventional bar and bracket method and Ash & Lacy says it is more thermally efficient as less aluminium is used in its manufacture. The halter is available in various heights to allow enough insulation to be installed to meet the thermal requirements of building regulations.
    Ash & Lacy 912

    Straight up

    Chris Partington is an associate director at architect Peter Taylor Associates, a specialist in residential schemes for national developers What’s been your best specification?
    Bespoke composite 5m x 2m cladding panels for Global Switch in East India Dock. They were developed with Exterior profiles and were the largest in the UK at the time. They were fixed in four minutes with shoot bolts so that the building was weathertight in double-quick time. What’s been your favourite product innovation in recent years?
    ETFE has enabled challenging architectural solutions to be realised, such as the Eden Project. What construction product or material do you swear by?
    Reglit/Linit glazing channels come in and out of fashion but remain a good versatile glazing solution and diffuse light well. What material will you still be using in five years’ time?
    Brick is the backbone of British vernacular and will always be in vogue. What’s the most overused, cliched building product currently in use?
    Cedar boarding is inappropriately overused. I can forsee a plethora of contracts in 15 years to replace boarding as it has been incorrectly specified. What red tape keeps you awake at night?
    Retrospective application of the new Part M. The full impact has not yet been felt.

    Stone wool donated to housing scheme

    Rockwool has donated stone wool insulation for the roofs and floors of five timber frame homes being built by Habitat for Humanity in Peckham, south London. Habitat for Humanity is using 150 mm and 100 mm roll format in the roof and 50 mm for floor insulation. The charity says that it wanted to use Rockwool products for their acoustic and fire resistant properties as well as their energy efficiency.
    Rockwool 919