40% House

Penney Poyzer and Gill Schalom have completed the most thorough environmental renovation ever attempted of a Victorian house in Britain. They have tackled every aspect of its performance including insulation, heating, waste and water with a view to becoming as autonomous as possible.

The house is an 1898 three-storey five-bedroom semi detached villa in Nottingham. When they bought it is was, in Penny’s word’s “a thermal nightmare’. There was no insulation and heating was provided by electric bar fires and an immersion water heater. Although structurally sound, the house was in a very poor condition after twenty years of student lets.
 
Why did they want to do it?
Gill is an architect, specialising in environmental design and renovation. Penney used to work for the Global Action Plan and has recently achieved national prominence as the presenter of the BBC2 Series No Waste Like Home. After living on the experimental new build Hockerton Housing Project they wished to make the ‘philosophical and political’ case for addressing the existing housing stock – by taking on the most challenging house possible to be a showcase for environmental renovation.

About the Renovation

Insulation
The largest challenge has been the insulation of every external wall in the house, improving their thermal performance by 860%. As is common in Victorian and Georgian buildings, the best quality bricks are on the walls facing the street. To maintain their appearance these walls were insulated internally with plasterboard backed with 100mm of phenolic insulating foam. Great care was taken with detailing to reduce cold bridging- with careful fitting around corners and additional insulation at the base of walls.

Pictured: very careful detailing of the internal wall insulation around windows

The less attractive rear and side walls were insulated externally with 140mm of an eps foam insulation system supplied by Sto, and then rendered. The decision to use standard insulation materials was not an easy one for Penney and Gill but was taken on cost grounds. As Penney says “it would have taken us so long to save the money for eco-insulation that we would have lost any of the benefits’.

The loft is insulated with 400 mm of Warmcel insulation made from recycled newspaper, giving an insulation value nearly four times greater than current building standards. The floor over the cellar was insulated with 100mm of sheepswool between the joists held in place with fibreboard.

After much pondering, Penney and Gill decided to not replace the existing PVC double-glazing as it cannot be recycled. For the new windows they fitted timber frames holding triple glazing with a krypton gas fill.

Water and sewage
This is house is unusual among even ecohouses for its concern with water conservation. Two tanks in the cellar hold 2,000 litres of rainwater for flushing toilets, washing clothes and watering the garden. The toilets are a dual flush Swedish model that uses only 2 or 4 litres.

Pictured: Raintank (on the left) and sewage tank (on the right) in the cellar

Sewage is separated in a low maintenance Aquatron centrifuge. The liquids drain into the sewer and the solids are deposited in a large composting chamber. This has not yet needed emptying in five years. Penney and Gill’s future plans include recycling liquid sewage in a garden reed bed.

Fittings, materials and appliances
Penney and Gill have used a very wide range of ecomaterials for their interior finished. These include clay, reed and hessian as an alternative to plasterboard in the bathroom; eco paints using self-mix casein powder, or soya or citrus based emulsions; lino and sisal carpet on floors; and salvaged materials and furniture.

Heating
The heating is provided by an imported Italian Mescoli word burner, which transfers heat to a 1,100 litre heat store tank. Gill and Penney were skeptical of the wood pellet burners and chose a model that can handle the small pieces of wood readily available as waste and trimmings. The total cost of the system was £5,000 of which £3,400 was met by grants. In summer all water heating is provided by a 4m2 flat plate solar panel. 

Pictuted: Penny loads up the wood boiler

What were the main obstacles they encountered?
The main obstacle was funding the project. They had to implement their plans in installments as they saved the money to pay for it, and found themselves living for years in a semi-finished house.

Penney and Gill had a very positive experience of their dealings with their local authority (Ruchcliffe Borough Council), which was ‘very supportive’. However, they had a major struggle with the government’s Clear Skies programme, which offers substantial grants for biofuel heating systems. The registered installer imposed by the scheme as a condition of funding recommended a boiler that was not recognized under the Clean Air Act. Penney and Gill found themselves fighting a test case – “the price we pay for being freaks” says Penney. The case was ultimately won because the local authority, which implements the clean air legislation, approved the wood burner. Penney says that Clear Skies had clearly not given any thought to the policy details for implementation and had recommended an installer that was inexperience in domestic installation of this kind of system.

How did they find out what to do?
Penney and Gill already had extensive contacts with other eco-renovation specialists and pioneers but still found they had to do a great deal of research. They found the Green Shop and Construction Resources were a great help for advising on materials, and recommend the Autonomous House by Robert and Brenda Vale as theoretical reading. At the time there was a very limited range of products available in the UK, almost all of which were imported from Germany, Sweden or the Netherlands, although the product range has increased dramatically during the past few years.

Top tips
1. Finding the builders. The Association for Environmentally Conscious Building is a good source of specialist builders. Sustainable Energy Action in London runs a ‘green register’ of construction professionals who have attended its two-day intensive course in environmental building. It is an excellent place to find people who understand the basics and have the interest and commitment to do a good job. Failing this, Penney recommends their own course of action – finding an inexperienced but willing ‘jobbing builder’ who they trained up themselves.

2. Get a big house. Penney and Gill found that it made sense to buy a large house so that they could live in one part of the house whilst work is carried out in another and, once refurbished, generate a long-term income from lodgers.

What were the improvements in energy performance or the carbon savings?
Before the changes, all space and water heating was electrical. If supplied from conventional grid electricity this would have represented very high emissions of nearly 19 tonnes of CO2/year. Improved insulation and air tightness halved the heating load. Once the solar and wood heating is factored in, the house energy emissions fell to 2.9 tonnes CO2/year, an 85% fall in emissions.

Contact
The House is sometimes opened for tours. For further information contact Penney and Gill at nottinghamecohome@ntl.com

Further information. There is a web-based guide to the house at http://www.msarch.co.uk/ and a pdf presentation on the house can be downloaded at www.coinet.org.uk/ecovation