How to Brief and Appoint a Retrofit Designer

Appointing the right retrofit designer is fundamental to delivering a successful PAS2035 project. The designer's role encompasses energy assessment, technical specification, coordination with other professionals, and ensuring compliance throughout the retrofit process. This guide outlines the essential steps for briefing and appointing a retrofit designer effectively.

Defining Your Project Scope

Before approaching potential designers, establish a clear project scope:

• Identify the building type and construction era
• Confirm the retrofit ambition level (fabric improvements, heating upgrades, renewable energy, or holistic approaches)
• Define budget parameters and timeline constraints
• Clarify whether the project requires listed building consent or conservation area approvals
• Establish occupancy expectations and usage patterns

Having this information ready allows designers to provide realistic proposals and identify potential complexities early.

Identifying Designer Qualifications

Retrofit designers must demonstrate competence across multiple disciplines. Look for evidence of:

• PAS2035 accreditation or equivalent retrofit-specific training — designers should have completed formal PAS2035 training and understand the Standard Assessment Procedure (SAP) or Simplified Building Energy Model (SBEM)
• Professional credentials — membership of RIBA, CIBSE, or equivalent professional bodies provides assurance of continuing professional development
• Practical retrofit experience — request examples of completed retrofits at similar scales and with comparable building characteristics
• Building physics knowledge — understanding of thermal bridging, air permeability, moisture management, and ventilation is essential
• Multi-disciplinary perspective — designers should coordinate with structural engineers, M&E specialists, and heritage consultants where necessary

Preparing Your Briefing Document

Develop a comprehensive brief document covering:

1. Building information: construction type, age, current condition, dimensions, orientation, and existing systems
2. Energy performance targets: desired EPC rating or specific energy consumption reductions
3. Retrofit priorities: identify whether fabric-first approaches are required or whether hybrid solutions (improved fabric plus renewable energy) are acceptable
4. Constraints and opportunities: listed building status, conservation areas, planning restrictions, access limitations, and opportunities for integration (solar orientation, district heating networks)
5. Budget and programme: available funding, phasing requirements, and expected project timeline
6. Occupancy considerations: whether retrofit occurs during occupancy, phased occupation, or vacant periods
7. Specific requirements: internal space constraints, aesthetic preferences, or tenant/owner expectations

Evaluating Design Proposals

When designers submit proposals, assess these aspects:

• Technical approach: Does the design follow a fabric-first hierarchy? Are measures sequenced logically? Are assumptions about existing performance realistic?
• Compliance clarity: How does the proposal address PAS2035 key principles and Building Regulations? Are SAP calculations transparent and justified?
• Coordination strategy: How will the designer manage coordination with structural engineers, M&E contractors, and programme delivery?
• Risk identification: Have potential issues (hidden defects, thermal bridging risks, ventilation complexities) been identified and addressed?
• Cost-benefit analysis: Is justification provided for proposed measures? Do proposals offer value for money?
• Fee structure: Are fees clearly itemised? Do they reflect the complexity and scope of design work required?

Establishing the Contract

Appoint designers using a clear contract that specifies:

• Scope of services: energy assessment, technical specification, design coordination, Building Regulations submissions, and post-completion responsibilities
• Deliverables: drawings, specifications, SAP calculations, compliance reports, and coordination documentation
• Timeline and milestones: design phases, submission deadlines, and approval processes
• Fees and payment terms: total cost, payment schedule, and arrangements for variations
• Design team coordination: clarify the designer's role in coordinating with other consultants and contractors
• Responsibility for compliance: confirm the designer's accountability for PAS2035 and Building Regulations adherence
• Liability and insurance: ensure appropriate professional indemnity insurance is in place

Ongoing Management

Once appointed, maintain effective designer engagement:

• Establish regular design review meetings during the development phase
• Request progressive refinement of calculations as the design develops and site information improves
• Ensure clear communication between the designer and on-site contractors during implementation
• Confirm that the designer remains available for technical clarification during construction and commissioning phases

A well-briefed retrofit designer with appropriate qualifications and clear contractual arrangements significantly improves project outcomes, reduces technical complications, and ensures compliance with PAS2035 and Building Regulations requirements.