Lilac is a self-planned and managed co-housing community in Leeds, England. It embraces the concept of living sustainably and communally. Members of Lilac have their own individual homes but share financial responsibility, the land, the development and day to day management of the project. This supports greater resilience and provides permanently affordable housing.

Project Description

Aims and Objectives

  • ‘Lilac’ stands for ‘Low Impact Living Affordable Community’. The objective of the project was to design and deliver a replicable model of affordable, environmentally sustainable housing.
  • Lilac aims for its houses to be carbon negative, meaning they generate more energy than they use. The houses have solar roofs and are super insulated. They are constructed from natural materials (straw, timber and lime). Lilac is the first development of any scale in the UK to use strawbale construction.
  • Lilac’s unique financing model (called The Mutual Home Ownership Society (MHOS)) ensures its affordability for people on low or variable incomes who would not otherwise be able to access the housing market. Members of Lilac pay their housing costs through the purchase of equity units. Every member pays around 35 per cent of their monthly net income, and the income from these payments pays off the mortgage that financed the land and development costs. In addition, Lilac has chosen to detach the value of the equity units from the property value, removing the possibility of speculative investment. Instead, the value of Lilac equity units are linked to earnings ensuring they remain affordable in perpetuity.

Lilac is a community of 20 households built on the site of a demolished school. It is located in a suburban area of Leeds in the North of England. It was first conceived by five founding members in 2006 and was fully completed in 2013. The community is founded on cooperative principles, with emphasis on low impact living (low embodied carbon, reduced energy consumption and other aspects of shared living which minimise environmental impact).

Lilac has created a new community. The site is intentionally designed to encourage interaction. Members all participate in one of nine management teams (called task teams) that run the site, provide social events with the neighbouring communities and offer training to emerging projects that are interested in replicating features of Lilac.


The UK has a strongly embedded culture of property investment. This can be problematic in areas where demand for homes outstrips supply and prices are consequently high. Where demand is high, property investors often have the means to outbid local households.

Much of the UK is experiencing problems related to housing quality, affordability and supply. Older properties by and large have very low energy efficiency and although newer properties more often have improved energy efficiency features, traditional building materials and construction techniques are still accompanied by high levels of energy and carbon usage.

Highly sustainable housing is still a small niche in the UK. Consequently materials and skilled labour are hard to find and expensive.

Key features

The challenge for Lilac was that building houses using unorthodox materials and techniques is usually very expensive. Until Lilac nobody had managed to build a housing development in the UK that combined very high environmental standards with affordability without large amounts of grant. Lilac achieved it through careful hands-on management of the development. This succeeded in reducing development costs to 18 per cent below the costs of building conventional houses. This, in conjunction with its innovative finance model, enabled the cost of the development to be shared with people across a range of incomes. The distribution of debt across the project is spread equitably enabling both lower and higher income households to access the housing, each being allocated equity units in proportion to their income.

What impact has it had?

Lilac has received widespread, sustained interest since the project was established, with attention from local, regional and national media. The project is frequently showcased as an example of best practice in housing, community-led housing, and low carbon living, and has received or been nominated for several awards across the Building and Construction sector.

A £45 million community right to build fund was launched by the UK Government in 2013 during a ministerial visit to the project. The Mutual Home Ownership Society (MHOS) model was also featured in a paper published by the London Mayor’s office, exploring innovative new housing tenure types for the capital.
Lilac is actively engaged in knowledge sharing to support growth in community led housing and help transfer its model. It is well known across the community led housing movement in England and often used as a model of best practice to inspire new entrants, and showcase methods of environmentally sustainable building.

How is it funded?

The project was financed through contributions from members (all members paid an initial deposit) a private development loan (mortgage) and a grant. The gross project cost including land, construction and professional fees was £2.95 million (approximately US $5million). This funded building 20 homes: 8 houses and 12 flats, and a common house, over a 0.7 hectare site. The development loan (covering 70 per cent of project costs) was supplied by ethical bank Triodos at commercial rates over 25 years.

Lilac was awarded a government Energy and Climate Change grant of £400,000 to experiment with straw bale construction.

The affordability aspect (the Mutual Home Ownership Model) is achieved by fixing member contributions at a set cost of a maximum of 35 per cent of monthly income. The range of incomes means that higher earners acquire more equity (but no more than 20 per cent more than a low income household in the same size property) than lower earners but everybody pays the same proportion of their earnings towards housing costs.

In order for the model to work member contributions must cover the loan payments, ongoing maintenance and service costs. The community uses any excess income gained through this model to build up a central reserve fund, which can be used to protect against financial shocks such as members losing their job, or to finance the difference between a high earner leaving and a low earner joining. Financial gaps from equity repayments when members leave are covered through incoming member contributions, bridging allocations between existing members, additional loan financing (against increases in value), or the central reserve fund.


Why is it innovative?

Lilac is the first cohousing project in the UK to combine low impact living with the Mutual Home Ownership Society affordability model. The decoupling of the value of Lilac homes from local house prices prevents the use of the homes as a speculative asset. It is also the first project at scale to use strawbale as a key part of its sustainability plan. Deliberate design features combine with an emphasis on community and sharing work to minimise environmental impact, and offer a replicable model for alternative housing supply.


What is the environmental impact?

Lilac’s approach to low impact living led to key choices across four areas: building fabric, micro-renewables, community design and behaviour issues (regulated through community agreements). The project focused on high performance and natural construction materials (straw, timber and lime) with energy efficient properties and low embodied energy. The Lilac energy strategy lists the following criteria: low impact; future proof; comfortable; reliable; reduce demand as a starting point; easy to use and maintain; appropriate to needs; affordable; understandable and demonstrable; designed to minimize external/additional resources; locally sourced and serviceable.

Lilac used a prefabricated strawbale and engineered timber system called Modcell for the construction of the houses. Straw is compressed into timber frames to create a proprietary building block. It offers advantages over traditional strawbale building in terms of structural strength, building insurance and ease and speed of construction.

Strawbale construction delivers low embodied carbon in the materials used. Carbon is stored and then locked up in plant based construction materials. One 16kg strawbale is the product of 32kg of carbon dioxide removed from the atmosphere for photosynthesis, making the construction itself carbon negative. A typical 100 m2 house constructed from Modcell stores and isolates 43 tonnes of carbon dioxide, compared to an average UK house, which produces 50 tonnes of carbon dioxide during construction. Modcell homes also have a reduced energy demand, with a reduction in energy consumption of up to two thirds compared to an average UK home.

The community embraces sharing as a way of reducing energy consumption. The site was designed with a shared common house and garden, and a car-free home zone in the centre. Cycling and walking is promoted in the site design. There are 10 car parking spaces on the site (half a space per dwelling) and 50 cycle spaces. Fifty per cent of cars are pooled either by Lilac or by groups of members. Allotments form part of the site, providing locally produced food and reducing the food-related carbon footprint of the residents. There are twenty five active gardens, including five which are made available to local residents outside of Lilac. Recycling is encouraged, including on-site composting facilities to recycle all domestic food waste.

The site also features solar panels, (a 28KWp (kilowatt peak) solar PV array), Mechanical Ventilation with Heat Recovery (MVHR) units and high efficiency gas boilers. All the three and four bed houses also feature solar thermal water heating. There are water butts and a pond for sustainable drainage. The use of locally sourced straw and timber added value through the use of local supply chains. The local assembly of the Modcell panels also provided opportunities for residents to be involved in elements of the build.


Is it financially sustainable?

Lilac is financially stable with built in mechanisms to hedge against financial risk and to protect the long term affordability of the homes. Members own the site collectively as a Mutual Home Ownership Society. All households contribute 35 per cent of their monthly income towards servicing the mortgage on the site, building up equity units which can be sold to incoming members at a value determined by changes in wages when they leave. Members pay a deposit equal to 10 per cent of the equity units they can afford to finance through their monthly payments. The number of equity units allocated to each household depends on their income and the cost of their home. The cost of each home reflects the build cost of the property, plus a proportion of the cost of the land and a contribution towards shared facilities and maintenance. Households are allocated equity units according to what they can afford to finance. Higher earning households effectively service more of the Society’s debt and acquire more equity units as a result.

If a households’ income falls, they can sell shares to a willing buyer from within Lilac, draw on the reserve fund (built up over time through surpluses generated by the system of payments), or convert to a rental tenancy at a reduced rate. If 35 per cent of a household’s monthly income is greater than the amount needed for the monthly debt repayment which they are responsible for, the surplus is split between a faster repayment of their overall debt and the reserve fund. Once a household has paid off their debt allocation their monthly housing cost drops to 10 per cent of their net income, any surplus once they have made their monthly contribution for the management and maintenance of the site, goes to the central reserve fund. People can also move between properties within the scheme, as they become available and as their housing needs change, provided all equity shares can be financed between members.

If a member leaves the cooperative after less than three years, their equity units are refunded at their original value (or lower if their property value has fallen). After three years if a member leaves, they receive 75 per cent of any change in the value of their shares, which is indexed to changes in the national average income, rather than local house prices.

Over the longer term, once the capital debt on the site is repaid, Lilac will be able to reduce the minimum income required for new members as the overall cost to be shared will be lower.

Living in Lilac reduces costs for members through fixed affordable housing payments, lower energy costs as a design feature of the site, shared facilities eg tools and cars, social events shared meals and self-reliance through food growing. Over time the community plans to increase self-reliance through increasing its ability to obtain work, food and energy on site and through the project.


What is the social impact?

The principles of sharing, mutual support, self-management and resilience embraced by Lilac encourage greater community interaction and integration. This is designed into the layout and features of the site, the finance model, as well as the culture and principles which members sign up to. Lilac also regularly holds events and activities, such as a monthly Folk night, which encourage involvement with the wider local community.

Developing and delivering Lilac helped members to acquire skills in various aspects such as design and planning, project implementation and management and expertise in the Mutual Home Ownership Society financial structure. Members also acquired skills and knowledge by participating in the build phase during the construction of straw bale timber cells.

Lilac is managed by task teams covering different aspects of site and organisational management, developing team members’ personal skill sets and improving the resilience of the community. Member education and skill sharing sessions are provided to encourage the transfer of knowledge across a range of activities like management, practical skills for sustainable living and social skills for living in a community.

The project encourages healthy living through limiting car usage and encouraging cycling and walking. Each household has an allotment for growing fresh food and providing opportunities for fresh air and exercise. The organic produce is used in communal meals, preserved or given away, increasing everyone’s access to free, healthy food.

The design of the site intentionally fosters community interaction and increases passive surveillance, deterring anti-social behaviour. Car reduction and separation also means children can play safely in the communal areas of the site.

The project helps to reduce social inequalities between residents through shared facilities, services and space. Every member is expected to contribute equally to the management of the project. The Mutual Home Ownership Society model provides an equitable cost arrangement for members, which reduces inequality for both current and future households. Membership generates high levels of trust as personal financial information, normally considered to be sensitive, is shared with task teams and helps to challenge cultural attitudes to wealth and income. Sharing resources also helps to reduce inequality between high and low earners across the community. High earners are not disadvantaged as their additional contribution enables them to buy additional equity units.

Lilac supports individual empowerment and active involvement in society through consultation, social events and participation in local groups and activities. Members coordinate and host many community events. The model of affordability also enables a range of household types to form part of the community including freelance, part time and retired households, who would otherwise be unable to access the quality of life offered.

The project has increased the wider community’s access to green space, providing five local residents with allotments and keeping the ‘pocket park’ (a small wooded area) open to the public.

Through the mutual support the community can offer, individual members have been able to offer shelter for vulnerable people, such as asylum seekers and homeless individuals.



  • The Mutual Home Ownership Society (MHOS) model is complex and had not been fully tested before being adopted by Lilac. To support understanding of MHOS, a user-friendly software interface (Dwell) was developed to support members to manage leases and report maintenance issues. There are many ground breaking legal and accounting challenges which Lilac as the first MHOS has to surmount. The Society is committed to sharing its on-going learning to make it easier for others to benefit from the advantages of the MHOS structure.
  • Over-reliance on a small group of founders created work and knowledge hierarchies. Lilac applies democratic decision-making, detailed planning and shares tasks widely across a number of task teams. A central Hub of members oversees the governance of the project, monitors workloads and potential issues as they emerge.
  • Many challenges were encountered in the build phase as some elements of the build were being trialled and were unfamiliar to the construction workers. A close working relationship with the project team and a more interactive and deliberative form of decision-making was required to solve problems.
  • Lilac has limited capacity to fulfil requests for advice and support. They are engaged in collaborative working with the community-led sector in the UK (particularly in the North East) to build up an infrastructure of support.
  • Support for community-led housing in England is limited, and a very high level of commitment is required. The initial development of the Lilac community benefitted from many members having a background in the co-operative movement. Lilac also received support from a wide range of other organisations with an interest in the project.
  • Navigating the Planning system in England presented a major barrier. Organisations and institutions showed a lack of understanding or resistance to the concept of a community-led project. Lilac has increased awareness and understanding and continues to work towards creating positive cultural change.


Lessons Learned

  • In the process of designing and delivering Lilac a number of aspects emerged which could be helpful in successful transfer. These relate both to the group itself and to external agencies that are actively engaging with similar groups.
  • Project timings should never be cut short at the expense of good group formation. There is a need to be realistic about group capacity, time and the actual length of the development journey. A healthy, functioning group needs to contain a variety of personality types – certain personalities are more effective at different stages of the process. Effective internal communication is essential – protocols and templates really help.
  • Groups should ensure they bring in professionals at the right stages; too early or too late will either lead to erosion of autonomy or over commitment, confusion and possible collapse. Getting advice from experts who seek to inform rather than influence is crucial for group independence. In addition, groups must be able to competently assess risk, to confidently make choices about costs, procurement routes or contractors. When the group communicates externally, clear and assertive channels are essential. Lilac had a single point of contact which gave external contractors a clear line of communication.
  • For practitioners involved in supporting community groups, taking co-production seriously and doing it well is vital. Appropriate facilitation skills are needed and activities should be meaningful rather than tokenistic. Extracting ideas without consistent communication can lead to crude reinterpretation of information and a loss of meaning and values. Designating a consistent representative to communicate with the client group builds up trust, continuity and coherent information flow. Practitioners should be prepared to work with a detailed project brief and review it periodically to ensure the project is consistent with initial intentions.
  • Different types of development contracts can lead to very different outcomes. Secondees from community organisations can be helpful for developers, acting as interpreters between the professional and the community. The process supports developers to understand their client group.
  • Mechanisms which support more equal relations could help support community-led housing. The finance and land sector would benefit from improved understanding of community self-builders and custom-builders. There is also room for improvement in the way state institutions engage with community-led groups. A process of improved understanding and freedom to innovate within statutory agencies would be beneficial.
  • The involvement of skilled accountants early in the build project would be helpful. Learning is ongoing in community life, and also in the legal and financial arenas as new situations are tested out in the changing community.



The key indicators of success relate to high levels of resident satisfaction and low member turnover.

Following completion of the site, residents started work on a number of project weaknesses, including high transaction costs and time needed to self-manage the project. These weaknesses will be addressed across a number of areas including finance, legal, landscape, shared facilities and maintenance.

Environmental monitoring was conducted following site completion, through a two year building performance and evaluation study, led by the University of Sheffield.



Lilac has supported emerging cohousing groups locally, particularly in Leeds and Yorkshire. Regular support is provided to other emerging groups. These include Chapeltown Cohousing (Leeds), ShangriLeeds, Bradford Cohousing, 5 Rivers Cohousing (Sheffield), Hebden Bridge Cohousing, York Cohousing, Hedben Bridge and Todmorden Community Self-Build CIC and Yorspace (York).

Many groups have attended events and used the common house as a resource for practical and social gatherings.
Lilac’s “Learning, Research and Replicability Task Team” is dedicated to knowledge transfer. The Society hosts regular ‘learning days’ on site and delivers many additional tours and talks on request.

A special full-day workshop on the Mutual Home Ownership Society (MHOS) model has also taken place, attended by representatives of nine emerging groups from across the UK. A number have gone on to register as MHOS and are actively progressing.

As part of the national community-led housing movement, Lilac has been working with a collaboration of local organisations (including housing providers, environmental architects and homelessness charities) to establish “Leeds Community Homes” as an ‘umbrella organisation’, which can use Lilac as an example of best practice to develop a city-wide framework to support community-led housing. This will be replicable in other cities and towns across the UK, offering solutions which enable more people to participate.