RIBA Stage 4 Design | Sydenham Homes

At Mark Fairhurst Architects, RIBA Stage 4 design represents a critical stage where concept ambition is translated into buildable reality. At this stage, concept ambition is translated into buildable reality. In particular, our work on two new-build houses at Windfield Close, Sydenham, exemplifies this process, bringing together regulatory compliance with thoughtful, high-performing residential design.

RIBA Stage 4 Design: From Concept to Construction

Following earlier design stages, the Stage 4 package for these two homes focuses on technical coordination, performance, and compliance. Specifically, the proposals involve the demolition of existing garages and the construction of two contemporary, two-storey houses.

As a result, this stage consolidates input from across the consultant team, including architecture, structure, energy, drainage, and acoustics. Consequently, the design is fully coordinated and ready for construction.

A Fabric-First, Low-Energy Approach

A key priority in the technical design is energy performance and sustainability. To achieve this, the homes have been developed with a fabric-first strategy, carefully optimising the building envelope before introducing systems.

For example:

• Highly insulated cavity walls and warm roof construction
• Triple-glazed aluminium windows with thermally broken frames
• Air source heat pumps replacing traditional gas boilers
• Mechanical ventilation with heat recovery (MVHR systems)
• Green roof elements and sustainable drainage measures

Together, these measures support compliance with Part L and help future-proof the homes against evolving environmental standards.

Designing for Comfort: Overheating, Ventilation & Acoustics

In urban residential design, performance goes beyond energy use. Therefore, the Stage 4 package addresses comfort and well-being through a coordinated approach.

Firstly, dynamic thermal modelling has been undertaken to meet Part O overheating criteria.
Secondly, a balanced ventilation strategy combines MVHR systems with opening windows for purge ventilation.
Finally, enhanced acoustic performance is achieved through robust party wall construction and pre-completion testing.

As a result, the homes are designed not only to meet regulations, but also to provide comfortable, healthy living environments throughout the year.

RIBA Stage 4 Design and Structural Coordination

Stage 4 also ensures full alignment with Building Regulations across all disciplines. In particular, the design integrates safety and performance requirements from the outset.

For example, fire safety measures include:

• Protected escape routes and 30-minute fire-rated stair enclosures
• A 1-hour fire-rated party wall between dwellings
• Mains-powered smoke and heat detection systems

Alongside this, the structural design plays a central role in delivering a safe and robust scheme. Specifically, the buildings are formed through a coordinated structural system, including:

• Strip and pile foundations, responding to ground conditions and load requirements
• Reinforced concrete retaining walls, addressing level changes across the site
• A timber and steel hybrid superstructure, combining efficiency with buildability

As a result, the structural approach is both practical and adaptable, ensuring stability while supporting the architectural intent.

Meanwhile, the drainage strategy incorporates sustainable urban drainage systems, including attenuation tanks and permeable paving. Consequently, surface water runoff is carefully managed, reducing pressure on the wider network.

RIBA Stage 4 Design Accessible, Adaptable Living

Both houses have been designed to meet Part M4(2): Accessible and Adaptable Dwellings. Importantly, this reflects a commitment to inclusive and future-proof design.

For instance, the homes include:

• Step-free or carefully managed access routes
• Generous circulation spaces and compliant door widths
• Ground floor WC provision with future adaptability
• Accessible positioning of controls and fittings

As a result, the houses can adapt over time to meet changing user needs.

Water Efficiency and Sustainable Infrastructure

Responding to planning conditions and environmental targets, the design achieves a water consumption rate of 105 litres per person per day.

To support this, the specification includes:

• Low-flow fixtures such as taps, showers, and WCs
• Efficient appliances
• Potential for rainwater recycling

At the same time, gigabit-ready digital infrastructure is integrated into the design. Therefore, the homes are equipped for modern connectivity from the outset.

Coordinated Delivery

At Stage 4, coordination is essential. As such, the project brings together:

• Architectural drawings and specifications
• Structural calculations and detailing
• Energy and overheating modelling
• Acoustic and arboricultural guidance
• Drainage and utilities design

In addition, further contractor-designed elements, such as MVHR systems, electrical installations, and commissioning, will be developed during construction. This ensures full certification and compliance at completion.

Conclusion: Building Confidence Through Technical Design

In summary, the Stage 4 submission for Windfield Close demonstrates how a well-coordinated technical design supports delivery. By aligning architecture, engineering, and regulation, the project achieves a cohesive and buildable outcome.

Ultimately, the result is a pair of homes that are efficient, compliant, and future-ready. Moreover, Stage 4 provides clarity and confidence for clients, contractors, and stakeholders as the project moves to site.