Naturhus

This Feasibility Study has been prepared for FIRE - the Findhorn Innovation Research Education Community Interest Company - as part of the Findhorn Ecovillage Feasibility Studies project that was carried out for the Scottish Government Just Transition Fund (JTF). The study investigates the potential of the Nature House (or Naturhus) model for dwellings located within a greenhouse enclosure, in the context of the Findhorn Ecovillage in northeast Scotland. The aims of the study are to develop a prototype design for a Nature House that is suited to the Findhorn Ecovillage context and local climate and to ascertain the benefits and challenges of realising such a building or buildings. The study chose to consider three potential developments of Nature Houses, ranging in scale from three, to six, to nine dwellings within.

The study was carried out by the following team:

• Arboreal Architecture - Tom Raymont (Project Lead)

• Integration UK - Alan Harries (Building Physics & Energy Modelling)

• Northwoods - Bernard Planterose (Construction and Cost)

• Christopher Raymont (Food Growing)

• Patrick McNamara (Job Creation)

We also wish to thank the following for their advice and support: Marilyn Hamilton, Michael Shaw, John Talbot, Tallis Tibo, Lorraine Rytz-Thériault, Giles Bruce (A-Zero Architects), Mizue Katayama (A-Zero Architects), Maria Daher (Arboreal Architecture), Simos Yannas (Architectural Association), The 4th year students at the Architectural Association

Origins

The nature house concept originated in the work of architect Bengt Warne in Sweden in the 1970’s, part of a first wave of sustainable design thinking that had emerged in response to writings such as Rachel Carson’s Silent Spring (1962). The sustainability movement was slowly expanding when in March 1972, a team of researchers and policymakers sounded another alarm in “The Limits to Growth”, one of the first reports to forecast catastrophic consequences if humans kept exploiting earth’s limited supply of natural resources. A conference in Stockholm - where Bengt was living - followed a few months later. Bengt’s vision for the nature house - see illustration right - was a building wholly enclosed within a glazed envelope that created a whole new set of spaces, not normally seen in domestic architecture. Instead of the usual split between interior and exterior, he proposed an intermediate temperate space where people and nature could be brought together. He imagined the space full of plants and connected to the cycles of the sun, wind and rain. He imagined that all the elements of nature - air, water, sun and soil - could be harnessed by the greenhouse space to directly meet the needs of the human inhabitants. He took care to draw the flows of water, heat and nutrients, almost as if the building was an organism itself.

Thermal Performance

One of the primary benefits of the Nature House model is the reduced need for active heating of the dwellings within, resulting in lower energy bills and lower carbon emissions. Thermal benefits are achieved in four different ways as shown on the right. The greenhouse space acts as a “buffer” creating a warmer and less windy environments around the homes than would otherwise be the case.

Health and Wellbeing

The temperate space of the greenhouse creates a unique environment around the homes that has benefits for health and wellbeing that are not usually possible in a typical dwelling. The greenhouse - being highly glazed - provides much higher light levels than a typical domestic space which can improve people’s mood (increased seratonin) and sleeping patterns. The greenhouse is also more highly ventilated than typical homes so has a better air quality (less CO2, more O2). The large open spaces in the design, coupled with the temperate and bright environment support people to be more active, engaging in exercise and food growing. Crucially, the Nature House is designed as a space for growing food as well as living within and we propose that each dwelling has 30m2 - 80m2 of growing space, depending upon how residents choose to use their available space (in particular, the first floor decks). This can allow each person to grow all of the fruits and vegetables in their diet if they wish, bringing benefits of fresher food and higher nutrition content. Salads and other vegetables tend to loose vitamin content in just a few hours after harvesting; a problem that home-grown can avoid. Residents can control the growing conditions, avoiding pesticides and other chemicals that are used on commercially produced food. Lastly, providing access to home-grown food reduces residents needs for more processed, lower quality foods with high fat, sugar and salt contents.

Health and Wellbeing

As well as the physical benefits described above, the Nature House offers important psychological factors that may well increase residents’ wellbeing. The designs incorporate larger open spaces than typical homes and these are shared by the people and families living within the Nature House. This spaciousness is valuable in itself and as an opportunity for neighbours to engage much more frequently with one another. Neighbourhood connections can develop a cohesive community and support network that can be invaluable for residents and their wellbeing through the challenges of life. These effects can contribute to a wider cultural change from a society of individualism and competition to one of mutualism and cooperation. In addition to the values of community, the Nature House - as the name suggests - offers the opportunity for residents to live in much closer proximity with nature than typical homes. Biophilia - the love of nature - is a universal phenomena and access to plants and experiences of the natural world can reduce stress and increase mental health.

Resources and Economy

The Nature House comprises timber-framed dwellings within a greenhouse enclosure that is highly glazed and also uses timber for its primary structure. The extensive use of timber sets the building apart from typical house construction that more commonly uses concrete block and brickwork - two materials that have much higher carbon emissions mainly due to the heat required to manufacture them. Glass, however, also has a high embodied carbon from its manufacturing so a key feasibility strategy has been the exploration of sources of reclaimed glass. Currently, across the UK, there is no recycling or reuse of construction (window) glass, resulting in 200,000 tonnes of waste. There is a tremendous opportunity for new circularity industries to be formed to turn waste streams, such as glass, back into useful products. Construction of the Nature House is conceived in two phases: firstly the greenhouse enclosure by a main contractor and secondly the inner homes as assisted self-build projects by the residents. This model promotes the autonomy of residents as well skills training that could lead to new jobs and enterprises. The large flexible spaces of the Nature House and communal facilities such as a commercial standard kitchen also support the posibility for small-scale and work-fron-home commercial initiatives. Lasty, the Nature House is designed to harvest high quantities of rainwater from its roof - not to waste the valuable resource of water - and thereby provide irrigation for the significant amount of food growing within.

The Nature House design principle has been utilised in many projects since its earliest definition by architect Bent Warne in the 1970’s in Stockholm, Sweden. The majority of these projects have been single homes, most often located in Scandinavia. The Nature House concept is particularly powerful for its synergistic combination of a wide range of complimentary ideas that emerge from the value of the greenhouse enclosure and the temperate space it creates. Considering the range of past Nature House projects, the Findhorn Nature Houses share some of the core ideas such as: 1. Using passive solar gain through the greenhouse (the greenhouse effect) to reduce the need for active space heating such as boilers or heat pumps powered by gas or electricity. 2. Using the greenhouse spaces for food growing by residents to improve their diet and reduce food costs. 3. Living in an environment surrounded by plants for the biophilic benefits of people and plants living closely together. The Findhorn Nature Houses also differ, however, in finding new or less common values in the greenhouse enclosure:

1. Building multiple dwellings inside a single greenhouse with aspects of communal living supported by common facilities for food growing, cooking, meetings and laundry.

2. Using the greenhouse as a protective environment that facilitates homeowners to self-build their homes.

3. Designing the greenhouse and core dwellings with attention to the embodied carbon of their materials so that savings in operational carbon are not gained at the expense of emissions from construction.

The proposed design is a relatively long, narrow building with one glazed side facing towards the south and one opaque, insulated side towards the north: half greenhouse, half regular house construction. This makes the most use of available solar gain, putting glass where there is plenty of radiation and opaque, insulated walls where there is not. The greenhouse enclosure is two-stories tall allowing for single story dwellings inside with some combination of roof deck and second story accommodation.

Space Use

The ground floor of the building is arranged with a communal garden at its centre alongside communal facilities of a kitchen, eating area, tool storage, toilets and a laundry. On either side of the communal centre, terraces of attached dwellings are arranged, varying in number according to the length of the overall building as constrained by its site. Three, six and nine units are currently proposed in three Nature House projects. Along the south side of the ground floor is an access path and more planting space.

On the first floor of the common area are lounge, meeting and office spaces. The homeowners may choose to use their first floors as an open deck for recreation and food growing, or to build additional interior space perhaps for another bedroom or home-office. Services, such as a hot water tank, may also be located here. At either end of the buildings there are large overhanging roofs that provide sheltered exterior space and stairs that access the first floor. Under the stairs is plant and storage space. Passive Design Strategies The buildings make extensive use of passive design strategies such as: • Solar gain - from the south facing glazing warming the greenhouse space and the dwellings inside.

• Stack ventilation - from openings at low level on the north and south sides and at high level on the top of the ridge.

• Wind driven ventilation - from openings on the north (leeward) side of the building at high level.

• Thermal mass - from a concrete screed proposed in the ground floors of each dwelling to regulate temperature swings in summer days and nights, thereby mitigating overheating. Materials and Construction Materials and construction systems have been selected in order to best satisfy the following criteria:

• Thermal performance (insulation and thermal gains).

• Low embodied carbon and high carbon sequestration.

• Structure and durability.

• Suitability for self-building strategies.

• Benefiting from the protections afforded by the greenhouse enclosure.

• Cost.

Foundations

Mass concrete has been selected for durability and is proposed in a small quantities as possible and without reinforcement so as to reduce embodied carbon. Steel screw piles may be considered for self-build dwellings and these are likely to be a similar embodied carbon to mass concrete.

Greenhouse Enclosure

Opaque walls and roofs are proposed to be timber framed using I-Joists (JJI by James Jones) as these provide a thickness that allows a high 04/ Prototype Design Proposal Sewerage There will be no connections to mains sewage. Grey water from sinks, showers, baths and all sources excluding toilets will be collected in exterior sand filter beds (approx. 200-400m2 ) where it will be treated and pumped back to the water storage tanks for irrigation. Toilets will be composting double-headers, switched over at suitable intervals. Electricity Power will be provided by mains electricity supplemented by PV panels on the roof and a battery. Electricity generated by the PV panels will be used in the common areas. Heating and Hot Water Hot water will be generated by electric heat pumps - either air source or ground source. If their is a viable collective project for ground source heating at the time of the development, this will be used. It not, each dwelling will have their own air source heat pump on the exterior of the building. level of insulation to be reached. Insulation is cellulose and/or wood fibre. External finishes and internal finsihes (where fire resistance is not required) are wood cladding. Plasterboard would be used where fire resistance is needed. Except for plasterboard, all of the structure, insulation and finishes are therefore wood or wood-based leading to a high level of carbon sequestration. The glass walls to the south and at the ends are proposed to be toughened glass while the roof would be toughened and laminated. These would achieve a suitably high level of safety for occcupants and meet Building Regulations. The glass would be held in aluminium frames and mounted to timber structural frames. This achieve the lowest embodied carbon whilst maintaining durability.

Reclaimed Glass

Glass has a high embodied carbon and it is estimated that building a six-unit Nature House from new glass would cause emissions of around 25-50 toness of CO2 e. The decarbonizing credentials of the project therefore hang on delivering a greenhouse enclosure without such high emissions. The proposed route is to use reclaimed glass which is not yet commercially available at scale but could be trialled as a pilot project. Glass that was reclaimed would have an embodied carbon of around 0.1% that of new glass.

Core Dwellings and Communal Structures

Core dwellings and communal structures are proposed to be built from Scottish timber frames with timber exterior cladding and cellulose insulation. Interior floor finishes are concrete screen (for thermal mass) and walls and ceilings are plaster for fire resistance.

Building Services

Fresh Water

Fresh water will be provided by Scottish Water mains run to the sites in underground pipework.

Rainwater

Rainwater will be collected from the roofs and stored in two large tanks for the purpose of irrigating plants.

Sewerage

There will be no connections to mains sewage. Grey water from sinks, showers, baths and all sources excluding toilets will be collected in exterior sand filter beds (approx. 200-400m2 ) where it will be treated and pumped back to the water storage tanks for irrigation. Toilets will be composting double-headers, switched over at suitable intervals.

Electricity

Power will be provided by mains electricity supplemented by PV panels on the roof and a battery. Electricity generated by the PV panels will be used in the common areas.

Heating and Hot Water

Hot water will be generated by electric heat pumps - either air source or ground source. If their is a viable collective project for ground source heating at the time of the development, this will be used. It not, each dwelling will have their own air source heat pump on the exterior of the building.

Citizens, Community and Place

The Nature House proposals offer a radically different way of living and sense of place than the typical approaches to housing in North-East Scotland. The collection of terraced homes inside a greenhouse enclosure with common spaces between is a fundamentally different model than a block of flats or a street of detached homes and gardens. In terms of density (units per area) it sits between these two norms and could be said to be like a block of flats that has been expanded allowing garden and growing spaces to enter in and around the dwelling spaces. The key principal of the Nature House is creating a shared temperate space around our homes in which plants and people can thrive.

Identity of a Place

Where volume housebuilders create rows of identical houses or blocks of identical flats, a Nature House is a unique place to live with a very clear identity. Gathering multiple dwellings under one glazed roof associates them with one another in a way that is far stronger than a street of homes or block of flats and this creates for the residents a strong shared sense of identity. When you say, “we live in the Nature House”, everyone will know where you mean.

Communal Living

The Nature House model provides generous amounts of shared space in the temperate area that is inside the greenhouse but outside the homes. This shared space is key to the communal potential of the Nature House. The communal space is largely intedned for food growing but social facilities of a shared kitchen, eating space, lounge, office, tools storage and laundry are also included. This arrangement provides an ideal setting for a group of people to live communally with one another, sharing resources and daily activities, being able to both retreat to the privacy of their homes and engage on the stage of the temperate space.

Multigenerational Social Spaces

The value of a warm, dry semi-public space in a North-East Scotland climate can probably not be overstated. In a typical street of homes or a block of flats, shared spaces are always exterior and this limits their usefulness and conviviality significantly, particularly for the young, elderly or more vulnerable. These people are likely to be house-bound in many scenarios but in a Nature House would have the opportunity to venture out of their homes without having to endure the wind, rain or cold. This could lead to very rich, multigenerational communities.

Enterprise Incubators

The opportunity for large areas of food growing space, coupled with communal kitchens offers a set of resources that could enable many different food and plant-based businesses to get started. The design offer residents enough food growing area to meet 100% of their own consumption of fruit and vegetables but also an interior roof deck space that, if used for cultivation, could provide an excess of crops that could be processed and sold. Some business trials might include food products such as jams and soups, health products such as soaps or cosmetics and take-away food provisions. Alongside the physical resources of the Nature House, the support of a vibrant community will also inspire and encourage people to take the leap into a new commerical venture. If it is a plant-based business idea, the Nature House could be a fertile test bed.

Empowered Citizens

The Nature House model offers the opportunity for people to build their own homes and grow their own food. By meeting these two most basic human needs with their own hands, head and heart, without relying on big businesses and expert “others” they are receiveing a powerful training in empowerment. The skills are practical and they may take them forward with the confidence to repair and extend their own home or others. They may pass them on to their children or offer to share their knowledge with others. But most of all, building and living in a Nature House brings the psychological gift of discovering you can do something you didn’t know you could. These Nature House citizens may be highly empowered and bring that attitude to their own lives and into the wider community.