Retrofit Design

Your dedicated Retrofit Designer will:

Review the Retrofit Assessment – a thorough review of the initial assessment to fully understand your property’s unique context and requirements

Develop a cohesive design – a comprehensive Retrofit Design integrating all required elements, including a robust moisture risk management and ventilation strategy

Ensure full compliance – navigating planning permission, conservation area requirements, and all relevant building regulations

Coordinate specialist input – seamlessly bringing in structural engineers, heritage consultants or other specialists where needed

Adopt a “fabric first” approach – prioritising the building’s fabric (walls, roof, floors, windows) to maximise energy efficiency before considering new systems, ensuring compatibility and long-term performance

– Risk Assessment & Mitigation Strategy, a thorough assessment of design risks and a clear strategy to manage them
– Detailed Drawings and Specifications, a full set of technical drawings and precise specifications for the planned measures
– Comprehensive Retrofit Design Report, a formal report detailing the design, performance targets, and PAS 2035 compliance

Yes – this is a core part of what we do. Solid-stone and traditional-construction properties within Conservation Areas often can’t use standard measures like External Wall Insulation, so our designers produce bespoke Internal Wall Insulation specifications and drawings instead, balancing energy efficiency targets against the moisture and breathability risks specific to older buildings.

Both. Our designers handle everything from standard cavity wall and loft insulation through to complex measures like Internal and External Wall Insulation, and Air Source Heat Pump design.

Rather than relying on generic manufacturer guidance, our technical team runs hygrothermal (WUFI) moisture-risk modelling on specific insulation products against a property’s real wall construction, testing whether a given system will introduce interstitial condensation risk before it’s specified – not after installation.

You don’t need to appoint separately. Alongside Retrofit Design, our in-house team includes award-winning Retrofit Assessors and Coordinators, so we can handle the entire PAS 2035 journey under one roof to streamline your project and reduce delays.

While we’re based in Bristol, our design team works nationwide – including current multi-unit building design work for Codi Group, a South Wales housing association, supporting both the Welsh Housing Quality Standard (WHQS) 2023 and the Optimised Retrofit Programme (ORP).