Cambridge University Self-Build Society

Why self build

New residential houses are built by either

  • speculative builders, who intend to sell immediately after construction;
  • self builders, individuals who intend to live in the new house themselves;
  • governments, mostly in order to satisfy a need for lowest-cost social housing.

House designs in speculative developments are solely optimised with regard to the builder’s profit margin, within the constraints set by local planning conditions, building regulations and buyers’ perceptions. The result are usually high-density developments that are advertised, and judged by most buyers, based on rather superficial features, such as internal finishes or kitchen furniture. Speculative builders have little incentive to pay attention to less visible design aspects, such as high-quality thermal and noise insulation, modern heating and ventilation concepts, energy consumption, future proofing, sustainability and maintainability. Such aspects are only taken into account to the degree enforced by planning regulations, which lag decades behind the state of the art, and are far less ambitious than what may be appropriate and achievable for a particular development.

Self-builders, on the other hand, have every incentive to design their house in a way that maximises their longterm usability, convenience and cost effectiveness. Self-built houses are optimised to match the needs of their future users. Where land prices permit, self builders typically aim for far more pleasant ratios between built room area and plot area than speculative builders. They are far more interested in innovative state-of-the-art materials, building technology and sustainable design concepts.

Britain is exceptional in having one of the lowest self-build rates in Europe. Only slightly more than 10% of all new homes in Britain are developed by their future owners, although this figure has increased over recent years. The result is a highly conservative and homogeneous housing market dominated by speculative developments, where innovations arrive decades after they have become common in other countries. Speculative builders prefer to work with least-common-denominator designs, that are replicated in a homogeneous cut-and-paste fashion across large sites. Quality home features, that have long become commonplace in many other European countries, such as basements, underfloor heating, solar/geothermal heating, high thermal efficiency (e.g., PassivHaus or AECB-Gold standards), remain unavailable from commercial speculative developers in the UK.

Self building can also bring financial advantages. As a rule of thumb, the cost of a commercially developed new house is typically comprised of 1/3 land price, 1/3 building cost and 1/3 sales profit. Self-builders have the opportunity to save in the order of a third of the price of a new house while gaining detailed control over what they actually get. In addition, self-builders are entitled to a VAT refund for the building materials used.

The most difficult aspect of any self-build project is to find a suitable plot of land. Britain has had particularly restrictive centralized planning policies since the 1950s, and as a result of a policy shift in 1998 towards focusing development on “brownfield sites”, the vast majority of new developments within cycling distance of the University are now high-density apartment blocks.

Unlike in many other countries, it seems not to be common practice in Britain for local councils to buy up agricultural land, prepare an outline plan for the site, develop the infrastructure, and then sell individual plots, all financed by the price difference between land with and without planning permission. Instead, British local councils only earmark entire sites (often many hectares) for development. Formerly agricultural land is then usually sold as a single huge site directly by its owners to a single developer, who then takes care of the necessary road and supply infrastructure. Local planning officers remain reactive rather than proactive.

In such an environment, self-builders are restricted to either finding a suitable gap in an existing development, or to join up with other builders to develop the infrastructure for a larger site before splitting it up into individual plots. As a result, British home owners are far more likely to refurbish an old house rather than build a new one from scratch, often at comparable cost. However, the upgrades that are feasible with an existing house are rather limited, especially with regard to properties of the core structure, such as thermal insulation, ventilation, or the inclusion of a basement.

The current planning environment is obvouisly not encouraging self-build projects. A certain amount of lobbying and cooperation among prospective self-builders may be needed to overcome these obstacles and be able to compete with speculative developers for the land available.