Sherwood

A dramatic certified Passivhaus and Building Biology compliant new build home in a beautiful setting.

The new two storey building replaces an existing single storey construction, the quality of which was beyond refurbishment. The new building is a Passivhaus certified low energy building and follows Building Biology (healthy building) principles. The building is dug into the south facing slope with a curved turf roof so as to maximise solar gains and blend into the immediate surroundings. The design features a double heighted living space, forming a tower.

Whilst contemporary in its design, the materials and detailing used reflect local traditions. Natural materials have been specified throughout such as timber shingles, a green roof, timber windows and doors, untreated timber cladding and stone facing.

Permaculture Zone 0 strategies include:

Building Biology – healthy building design to Building Biology principles featuring non toxic materials, design out dust mite habitats, minimise electromagnetic radiation through wiring specification and design (radial wiring and EMR dampening switching), high levels of air quality, thermal comfort and daylight levels, potable water filtration and cleaning system

Passivhaus – low energy design to Passivhaus certified standards resulting in high thermal comfort levels, minimal CO₂ emissions and greatly reduced energy consumption

Daylight Design – is maximised in all spaces and habitable rooms where possible to reduce reliance on artificial light and utilise solar gain, which supplements internal heating levels

Thermal Mass – inclusion of thermal mass is provided in the load bearing ground floor construction using solid internal walls and floor slabs. Thermal mass reduces internal temperature fluctuations and helps reduce energy use

Super Insulation – walls to achieve high insulation levels and a U value no greater than 0.15W/m²K. Highly insulated roof and floor constructions achieve U values of no greater than 0.1W/m²K. All windows and doors are high performance with timber frames. In combination, these high insulation values minimise heat loss through the building fabric and significantly reduce energy use

Minimal Thermal Bridging – ensuring continuity of the insulation around the building through careful design, reduces heat loss and energy use and also prevents mould growth by eliminating cold spots

High Levels of Air Tightness – draught proofing and sealing all parts of the construction to Passivhaus standard achieves less than 0.6 air changes per hour and reduces heat loss, therefore further reducing energy use

Mechanical Ventilation with High Efficiency Heat Recovery – minimising ventilation heat losses through controlled ventilation (MVHR), ensuring better indoor air quality and reduced heating requirements by retaining energy from exhaust air

Low Carbon Technologies and Onsite Renewables – solar hot water panels in combination with photovoltaic panels provide energy efficient hot water and are sized to offset the building’s entire carbon emissions

Low Water Use Strategies – using flow regulators, low flush WCs, aerated taps and low water use showers, significantly reduces mains water use and costs.

Rainwater Collection – these systems recycle rainwater for garden use

Efficient Appliances – energy efficient lighting, controls and appliances, further reduce energy use

This holistic passive design strategy allows the house to be designed without a conventional heating system. At the same time, it will avoid overheating in summer and have minimal environmental impact.

The integrated landscape and building design approach demonstrated at Sherwood is a powerful model for how humans could be designed into their settlements to create a Permanent Culture.

The project at Sherwood is an integrated Permaculture design for a new build Passivhaus building with an integrated landscape design that provides the client with energy, food, water and shelter in a way that works with and enhances the natural environment.

Demonstrating how people can be designed into the ecology of a site so that they become part of the biological systems that make the site function, this scheme is a good example of Regenerative Design. The landscape design has been based around Permaculture zoning, reflecting frequency of use and placing design elements in the landscape to maximise beneficial relationships.

The landscape design has been designed to Permaculture principles which are organised into Permaculture Zones.

Permaculture Zone 1 – the landscape immediately around the building features:

• Inside/outside spaces include conservatory for solar gain and planting
• Covered areas for outside use when weather protection is needed
• Sun terrace for amenity use and access to gardens
• Kitchen garden terrace including raised bed herbs, salad and vegetables
• Green wall system to retaining wall
• Terrace fruit and dwarf rootstock espalier fruiting trees, some with movable cloches
• Terrace aquaculture ponds – taking key point surface water from adjacent land, rainwater overspill from the rain-water collection system and grey water system; used as irrigation for terraces; reflects sunlight into house
• Detached garage and poly-tunnel and potting shed for extended season planting and seedlings for site

Permaculture Zones 2 / 3 – the main areas for fruit and nut production including:

• Edible forest garden
• Bark pit and reed bed system for harvesting nutrients for growing green manure
• Workshop
• Large aquaculture pond – edible aquatic species and natural swimming pool fed from terrace aquaculture ponds
• Access way to other zones and for moving harvested produce

Permaculture Zone 4 – less intensive use areas including:

• Wildlife pond – large body of water to link reed bed system and aquaculture system
• Woodland edge planting including edible fungi areas
• Woodland coppicing along ex railway track for systematic fuel and craft materials harvesting and running track

Permaculture Zone 5 – wildlife area where human interference is reduced to a minimum and learning from observation is possible e.g. natural regeneration.

What the Client had to say:

‘We chose Gale and Snowdon largely because their ethos was similar to ours.  We wanted a highly energy efficient design with low running costs –  a healthy house with minimal impact on the environment – a design that enhanced its rural location, not detracted from it, and flexible internal spaces that supported rather than hindered the way we wanted to live.    Critical to the success of the project was the high level of skill, knowledge and experience provided by G&S who also happen to be lovely people to work with.

G&S worked with us to hone down our ideas of what the house should look like and how the internal spaces might meet our aspirations, both short and long term into retirement.  During this process, they helped us to push the boundaries of what was possible within our budget.  The team also includes a building systems specialist who ensured that renewables, ventilation, plumbing and electrical systems were fully integrated into a final design. This de-risks multiple problems – for example, potentially disruptive and costly reworking of plans to make space required for equipment such as air ducting.  G&S also helped us to think about how we could integrate the building into approx 6 acres of garden by adopting permaculture principles and methods to encourage biodiversity. 

Today we have a house that exceeds our initial ambition, came in on budget and also achieved Passivhaus Certification – which is the gold standard for low energy buildings and build quality.  

The whole experience of building a house, something we have not done before, has been enormously satisfying and incredibly rewarding.  We love being here and without very significant input from G&S the project would not have been so successful’