How change of use legislation is breathing new life into previously used buildings

When the Government widened permitted development rights last year, it signalled more than just another technical tweak to the planning system. The February 2024 amendments to Class MA of the General Permitted Development Order (GPDO) have the potential to transform the way our towns and cities evolve and the fortunes of many older buildings. Older buildings often leak air and resist high thermal performance, while thin walls and outdated windows can compromise acoustic insulation.

By removing both the three-year vacancy requirement and the cap on the size of buildings eligible for conversion, ministers have opened the door to a much wider range of commercial properties being repurposed for housing. In doing so, they have created new opportunities for investors and design professionals alike, and new life for buildings that might otherwise have stood redundant.

Successive revisions to the National Planning Policy Framework have called for greater use of brownfield land and higher densities in urban areas. For property investors, the appeal of Class MA conversions is that they can often be delivered more quickly than new build schemes, and at lower cost. That time advantage alone is critical in a market where financing costs remain elevated and exit strategies depend on speed of delivery.

But, for every legislative green light there are practical amber ones. Buildings originally designed for retail, office or industrial use rarely lend themselves seamlessly to residential life. The most persistent challenges are architectural: ensuring access to natural light and ventilation, upgrading thermal and acoustic performance, providing private and communal amenity space, and creating a sense of security and privacy in environments that were never meant to be homes.

For design professionals, the detail is everything. Deep floorplates can create gloomy, single-aspect apartments unless mitigated by courtyards or shallow layouts. Older buildings often leak air and resist high thermal performance, while thin walls and outdated windows can compromise acoustic insulation. Few local authorities will welcome schemes that produce cramped or awkwardly shaped units that fail to meet national space standards.

Even when the fundamentals can be solved, the solutions often fall outside permitted development. New windows, rooflights, balconies or boundary treatments may all require separate planning applications. The irony is that a process billed as simpler can be just as complex as a conventional application.

The key, then, is not to view Class MA as a universal remedy but as a filter for opportunity. Experienced designers know that the most successful projects begin with the right building. Properties that were once residential often convert most smoothly: they tend to have smaller, more frequent windows, shallower plans, and layouts that naturally support privacy and security.

For projects in which the existing shell is more problematic, a hybrid approach can work. Secondary applications can authorise additional alterations that make units more marketable – be it extra glazing for ventilation or communal gardens that lift the scheme’s appeal. Where contamination or structural integrity present insurmountable challenges, however, investors may be better served by demolition and rebuild.

What unites both the priorities for designers and investors is the value of early collaboration. Engaging designers and planning consultants from the outset allows investors to test viability against design constraints before committing capital. That collaboration also helps ensure that schemes meet both the spirit and the letter of Class MA: not simply delivering more homes but delivering good homes in sustainable and desirable locations.

The expansion of Class MA rights is best understood not as a silver bullet, but as an enabler. It has widened the field of potential projects, but whether those opportunities deliver will depend on intelligent building selection, thoughtful design, and careful financial appraisal.

Handled well, conversions can breathe new life into the historic fabric of our cities, provide much-needed housing, and demonstrate that adaptation is often smarter – economically and environmentally – than starting from scratch. Handled poorly, they risk producing units that are unsatisfactory for residents and underwhelming for investors.

The challenge, and the opportunity, is to see beyond the legislative headline and make conversions a genuine instrument of urban regeneration.

This article appears in the AT Journal issue 156, Winter 2025 as "How change of use legislation is breathing new life into previously used buildings" and was written by Nigel Booen, Director of Design, Boyer.

--CIAT

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