Before You Build: How Pre-Redevelopment Audits Set the Stage for a Greener Future
by James Morton
As London positions itself as a leader in sustainable urban development, the Greater London Authority (GLA) has integrated the Circular Economy Statement into its planning strategy. This framework prioritises the reuse and adaptation of existing structures, resource efficiency, and waste reduction in construction projects. Central to this policy is the pre-redevelopment audit, a critical process for evaluating the feasibility of redeveloping existing buildings. Beyond assessing materials, the focus is on analysing vertical and horizontal extensions, light and deep retrofits, and partial building retention to optimise both sustainability and functionality, suited to a single building.
Decision tree for design approaches for existing structures/buildings (https://www.london.gov.uk/sites/default/files/circular_economy_statements_lpg_0.pdf)
Why Pre-Redevelopment Audits Matter
Pre-redevelopment audits are more than regulatory requirements; they form the foundation for informed decision-making in sustainable development. In line with the GLA’s Circular Economy Statement, these audits are mandated for major developments in London. They evaluate the potential of existing buildings for adaptive reuse and redevelopment, ensuring that new projects are both environmentally and economically sound. By embedding sustainability into the early stages of a project, pre-redevelopment audits enable London’s urban growth to align with its environmental goals.
The Process: A Harmonised Approach to Building Redevelopment
A pre-redevelopment audit involves a comprehensive evaluation of the building’s potential for redevelopment, ensuring that structural, mechanical, electrical, plumbing (MEP), architectural, and groundwork considerations are harmonised. The aim is to create a cohesive strategy that balances sustainability, feasibility, and design innovation.
1. Comprehensive Feasibility Study
The process begins with a detailed site and structural assessment to determine the building’s adaptability for redevelopment. Key aspects include:
Vertical Extension: Assessing the structural capacity of the existing framework to support additional floors. This involves evaluating load-bearing elements, foundation integrity, and the feasibility of lightweight construction methods to minimise stress on the existing structure.
Horizontal Extension: Exploring opportunities to expand the building footprint while maintaining stability and integrating with surrounding infrastructure. Considerations include spatial constraints, structural reinforcements, and zoning requirements.
Partial Retention: Identifying which parts of the building can be preserved to maintain historical or architectural significance while minimising resource use. This includes assessing the compatibility of retained elements with new construction materials and designs.
2. Light and Deep Retrofit Strategies
The audit differentiates between light and deep retrofits based on the scope of work required to achieve the project’s objectives:
Light Retrofit: Focused on cosmetic upgrades and system optimisations, such as replacing MEP systems, upgrading insulation, and improving energy efficiency. These retrofits aim to modernise the building without major structural changes.
Deep Retrofit: Involves significant structural interventions, such as reinforcing load-bearing walls, replacing outdated systems, and reconfiguring layouts to meet contemporary standards. Deep retrofits are ideal for extending the building’s lifespan and enhancing its functionality.
3. Redevelopment Planning
The redevelopment process integrates multiple disciplines to ensure a cohesive outcome:
Structural Considerations: Evaluating and reinforcing load-bearing elements to accommodate extensions or retrofits. This includes advanced modelling to simulate structural performance under new configurations.
MEP Systems: Assessing the feasibility of upgrading existing mechanical, electrical, and plumbing systems to meet modern standards while minimising energy consumption.
Architectural Design: Developing designs that harmonise retained and new elements, ensuring aesthetic and functional cohesion. This includes optimising natural light, ventilation, and spatial layouts.
Groundworks and Foundations: Minimising disruption to existing foundations while ensuring they can support redevelopment plans. This may involve soil testing, foundation reinforcement, or partial reconstruction.
Deliverables of a Pre-Redevelopment Audit
The final audit report serves as a blueprint for the redevelopment process, detailing:
Feasibility Analysis: A thorough evaluation of the building’s potential for vertical and horizontal extensions, retrofits, and partial retention.
Integrated Redevelopment Strategies: Actionable plans that align structural, MEP, architectural, and groundwork considerations.
Environmental and Economic Impact Assessment: Metrics quantifying waste reduction, carbon savings, and cost implications.
Regulatory Compliance Documentation: Evidence of alignment with the GLA’s Circular Economy Statement and relevant planning regulations.
Next Steps for Redevelopment
Once the pre-redevelopment audit is completed, the next phase involves refining the redevelopment strategy and initiating detailed design and planning work. Key steps include:
Development of Detailed Plans: Collaborate with structural engineers, architects, and MEP consultants to finalise the design for vertical or horizontal extensions, retrofits, or partial retention. These plans should incorporate the findings from the audit to ensure alignment with sustainability goals.
Stakeholder Engagement: Engage with local authorities, planners, and contractors to ensure all proposed actions meet regulatory requirements and community needs.
Implementation Planning: Develop a phased construction plan, addressing logistical challenges such as material sourcing, site access, and coordination of workstreams.
If the audit concludes that redevelopment is not feasible and demolition is the most appropriate course of action, a pre-demolition audit should follow. This subsequent audit will focus on maximising the recovery and recycling of materials, aligning with circular economy principles and ensuring minimal environmental impact.
CE model, compared to the linear and recycling economies
Diagram courtesy of Circular Flanders
Conclusion
The pre-redevelopment audit is a critical tool for transforming existing buildings into sustainable, modern spaces. By focusing on the feasibility of vertical and horizontal extensions, light and deep retrofits, and partial retention, these audits ensure that redevelopment is not only environmentally responsible but also economically and architecturally sound. Through a harmonised approach to structures, MEP systems, architecture, and groundwork, pre-redevelopment audits enable London’s, and hopefully soon the rest of the UK, construction industry to lead the way in sustainable urban growth. As the city evolves, this process will remain pivotal in shaping a greener, more resilient built environment.