Constrained Sites

Unlocking London's most overlooked and challenging plots through intelligent, low impact design

From backland plots and brownfield land to tight urban infill and complex planning contexts, we have spent over 30 years turning limitations into opportunities for thoughtful, sustainable architecture.

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Constrained sites are often overlooked, but they hold huge potential.

These include:

Backland and infill plots
Brownfield sites and underused land
Sites with restricted access
Tight urban footprints
Heritage or planning-sensitive locations

These sites demand a different way of thinking, where every decision must work harder.

London urgently needs more homes, yet delivery continues to stall under rising costs, regulatory complexity and planning delays. Small and constrained sites are now recognised as critical to unlocking housing within the existing city, but are often held back by a one size fits all system. At RDA, we focus on unlocking these overlooked sites, using design and planning expertise to deliver high quality, sustainable homes in the most challenging urban conditions.

What makes these sites challenging

Working on constrained sites requires careful negotiation of multiple factors:

Limited footprint and buildable area
Daylight, overlooking and privacy constraints
Rights to light and neighbour relationships
Restricted construction access
Complex planning requirements
Structural and ground conditions

Each project demands a tailored response rather than a standard solution.

Our approach

We approach constrained sites through a combination of spatial intelligence, technical rigour and long-term thinking.

Reworking before extending

We prioritise reorganisation of existing space before adding volume.

Thinking in section, not just plan

Vertical layering, split levels and compact volumes unlock space where footprint is limited.

Maximising light and outlook

Careful positioning of openings, courtyards and terraces ensures quality of space.

Working with planning constraints

We engage early with planners and neighbours to shape viable proposals.

Low-energy, long-life design

Even on the tightest sites, we embed high-performance fabric and sustainable systems.

Constrained Sites Projects:

Eva's House

This compact contemporary family home was designed for a highly constrained 6 × 6 metre corner site in South East London, formerly occupied by garages and a scrap yard. Significant ground remediation was required, including the excavation and replacement of 1.5 metres of oil-contaminated soil.

Constructed using structural insulated panels (SIPs), the 100% timber structure, largely recycled, was assembled in just three weeks without steel. The adaptable 100sqm layout has evolved from two to three bedrooms, demonstrating long-term flexibility. Built to early Passivhaus principles, the house achieves excellent thermal performance with low energy use and is future-proofed for renewable technologies.

Despite its limited footprint, the design maximises natural light through a rear lightwell, with added outdoor space including a front garden and second-floor balcony.

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Passive Mews I

This project is RDA’s first certified Passivhaus, delivered on a tightly constrained infill site within a South London mews, to the rear of a Grade II listed building. Limited access, planning restrictions and the conservation setting presented significant design and construction challenges.

The original coach house lacked thermal efficiency, and the new home was designed to retain its industrial character. Constructed using structural insulated panels (SIPs), the modular system enabled off-site fabrication and efficient assembly despite the narrow access. A brick slip cladding system was used to reflect the surrounding materiality.

Built to Passivhaus standards, the house incorporates triple glazing and high levels of airtightness, reducing heating demand by up to 95% while significantly lowering carbon emissions.

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Passive Mews II

This three-bedroom certified Passivhaus, completed in 2017 for a budget of £250,000, was delivered on a tight infill site within a conservation area, with restricted access and planning constraints shaping the design.

The home features red cedar detailing and chamfered timber soffits, adding warmth and softness to a pared-back form. A concealed hydrotherapy pool is integrated within the scheme, powered and heated primarily by four large photovoltaic panels on the roof, supporting the home’s low-energy performance.

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The Modern Courtyard

This prefabricated home was delivered on a highly constrained former garage site, shaped by planning and noise restrictions as well as extremely limited access.

Designed in direct response to its overlooked cul-de-sac setting, the house is partially sunken to achieve generous ceiling heights and organised around two internal courtyards. These bring natural light deep into the plan while meeting amenity requirements, with carefully positioned glazing maintaining privacy. The restrained, industrial form creates architectural interest without dominating its surroundings.

Modular construction was integral from the outset. The house was split into seven prefabricated modules, fully fitted with glazing, services, and interiors, and assembled on site in just one day following extensive groundworks, offering both speed and cost control.

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The Old Stables

The Old Stables transforms a constrained backland mews site in East Dulwich into a compact live/work home, shaped by limited access, a tight programme and budget, and a dense urban context.

Designed to accommodate a ground-floor workspace with a self-contained studio above, the scheme uses a modular approach to unlock the site. Constructed from brick-clad SIPs panels, the building responds to its surroundings with a robust, industrial character, while bespoke window designs manage privacy and introduce visual interest.

Fabricated off-site and delivered in three modules, the structure was craned into position and assembled rapidly, with fit-out completed in just weeks. Informed by early thermal modelling, the 100sqm building achieves high energy performance while remaining adaptable and cost-efficient, delivered for approximately £150,000.

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