Lime Legal

Get with the programme

Published 04 September 2023

Michael Kohn on how a computer pattern book is helping people build quality homes in areas they want to live.

It’s easy to blame the economic downturn for all our woes. But if we look back to before the credit crunch, it’s obvious that the housing industry was already facing a crisis. Relying solely on private sector delivery was clearly a bad idea, yet the major criticism centred on the drab product, rather than on rethinking the process that created it.

The nature of speculative development is such that it distances the end user from the design process. In any other mass industry, excluding user feedback prior to production would be considered commercial madness.

But with housing, where demand outstrips supply and where securing planning permission and market value present major risks to the developer, feedback is replaced by an abstract – and conservative – assessment of ‘the market’ in general.

The pattern book approach means self-build can be organised at volume sale.

Potential residents of new developments are only engaged after designs are fixed and planning is won. There is never an opportunity for prospective householders to have an input on the design of their home or neighbourhood during design development stages.

Maybe that’s why there’s growing enthusiasm for building or developing your own home. Recent research indicated that 70 per cent of homeowners have considered building their own home. Self-build annual completions only account for about 10 per cent of new homes in the UK, but self-commissioned housing is much more common in Europe. (The figures are 55 per cent in Germany, 45 per cent in France).

The majority of prospective British self-builders never achieve their ambition, perhaps put off by the complexity and length of the process, but more likely because they were never presented with land on which to build. So, in the context of the growing housing crisis, why don’t local authorities tap into this latent demand, and enable people to develop their own homes?

At Slider Studio, we have long supported the idea, and put our weight behind a hybrid system combining the benefits of self-build with the efficiencies of volume house building. Our team of architects and software developers has come up with a method for organising self-build at volume scale. We call it ‘enabled self procurement’ or ESP for short.

Our plan is based on the splitting up of large public sector land banks into individual serviced housing plots by an ‘enabling developer’, and the plots being sold off with planning permission attached. The enabling developer would act as co-ordinater and would construct the roads, services and public realm, but also build out some houses as case study examples showing people exactly how to carry out the work.

The planning permission secured on each plot would be subject to a strict urban design code which controlled the overall massing, the type and tenure of housing and car parking arrangements. The permission would also reference an approved pattern book of home types suitable for that plot.

The pattern book house types would be assembled by the enabling developer in partnership with the local authority and ‘early adopter’ residents. In addition, the enabling developer would prepare and commoditise all other design, contracts and professional know-how needed to get housing built. The developer could also sign up local small builders to offer construction services to the emerging community, thus promoting local skills and economic regeneration in the area.

To develop the ESP model, we tested a 3D simulation, based on our YouCanPlan gaming engine, funded by UrbanBuzz and working with a range of industry professionals and academics to fully map out the process. The purpose of the simulation was to illustrate what the design outcomes in an ESP development might actually look like.

We ran a competition to find pattern book house designs that would allow enabled self-builders to customise and build their own homes – and we selected 10 designs for a ‘proof of concept pattern book’ for simulations. The simulations were then run online for the public to participate in. Participants could search the community for a plot they liked, selecting options from the online pattern book to assemble a customised house types on their individual plot. They could then publish their designs for viewing and comment by their prospective neighbours and the public at large.

The YouCanPlan simulation worked for two reasons – it helped people understand the home they were assembling on their plot and it helped them visualise the type of neighbourhood emerging around them. Importantly, it also suggested viable simulation tools for planning officers, offering a degree of certainty about an ESP development, illustrating how it might turn out after everyone had developed their plot using the permitted house types and urban design codes.

The simulation deployed the ten competition winning house designs of very different styles, but the pattern book approach could also be very prescriptive, ensuring a tighter aesthetic cohesion to the whole development, perhaps reflecting the local context, local planning policy, and views of existing neighbours.

A pattern book coupled with a design code is not so different an approach from some European models, and before planning law existed, much of Georgian London was built by small developers in this way. The important point is that for each ESP development, the agreed pattern book and design code is the key to capturing affordable design knowledge and removing the hassle from the process for the non-professional.

Over time, popular house types would emerge as being cost effective and favoured by end users, evolving regionally to suit different needs and markets. But unlike pattern books evolved by space-pinching volume house builders, an ESP pattern book, sponsored by the public sector for use on public sector land, could actually be open-sourced, shared nationally, honed through continuous feedback from people who have both built and lived in the homes.

Bad, impractical, spatially inadequate, underperforming or unnecessary design would thus be removed over time. Architects and system suppliers could be paid to contribute to this ever evolving people’s pattern book, updating and maintaining designs, as well as delivering construction management services on the ground on behalf of the enabling developer.

So how do we envisage the growth of a community over time?

Any ESP development can be broken down into three stages. In the first stage ‘early adopter’ households are able to take an option to purchase a plot of a specified size and orientation, according to their budget. The early adopters are in effect tied in partnership with enabling developer and local authority, working together to agree appropriate design codes and pattern books.

The second stage starts after planning is granted and the early adopters can then complete the sale of their specified plots at a reduced market price to reward their risk of participating in the first stage. During this second stage new parties also join, paying a bit more for their serviced plot to reflect its raised value with planning secured, but still saving money on the market price by joining at the build stage and enjoying the increased choice offered via the agreed pattern book.

Together, this growing community has increased capacity to co-ordinate contracts with local builders, approved and trained by the enabling developer, to assist them in the assembly and fit out of their new homes. A few homes would be completed by the enabling developer, and sold as shells to people to customise internally, and a few would be completed fully in the usual manner and sold at market prices, for people who do not have the time or energy to do the work themselves.

The final stage, when the construction is complete, is when the community begins to mature, cashing in on the social capital built up through the ESP process. When people finally need to move away, they would be able to sell back to the enabling developer.

3D simulation gives self-builders the chance to visualise the layout of their home and the neighbourhood.

We believe there are a number of emerging financial and legal models, including the community land trust model, for which ESP offers attractive benefits. But in whatever legal framework ESP is deployed, the enabling developer always reduces his market risk because he has partnered with a significant sample of the local market, and has already sold options on serviced plots – we imagine up to 20 per cent.

The developer also reduces planning risk because the local community and planning officers are consulted from the outset, and the application is backed by the early adopters who want to develop and live in the community, and these local people would be seated right behind the enabling developer in any contentious planning committee meeting!

So if the UK needs more better quality homes, set in neighbourhoods where anyone would want to live, surely the most direct way is to get the communities to develop them for themselves? Local authorities should be encouraged to team up with enabling developers to create favourable conditions to support micro and small scale development opportunities, and only then will we get the type of housing we all deserve.

Michael Kohn is an architect and founding director of architects and software developer Slider Studio. Enabled self-procurement is further explained and illustrated on