Retrofit
assessments.

What PAS 2035 is

PAS 2035 is the publicly-available specification that governs how retrofit work is carried out on existing dwellings in the UK. It defines who does what, in what order, and to what standard — with the goal of avoiding the moisture, comfort and air-quality problems that retrofit done badly can introduce.

A PAS 2035 project is led by a Retrofit Coordinator and supported by a Retrofit Assessor (the role I provide), a Retrofit Designer, and the installer. The Assessor produces the foundational document — the Whole Dwelling Assessment — that the rest of the team designs against.

When you need an assessment

• ECO4 funding. Mandatory for any measures funded under ECO4 or the Great British Insulation Scheme.
• MEES exemption applications. Useful evidence when registering an exemption from minimum energy efficiency standards on grounds of cost, character or consent.
• Self-funded retrofit projects. Recommended where the homeowner is investing £10k+ in fabric or systems and wants the work coordinated against a proper plan rather than installer-by-installer.
• Listed and traditionally-built homes. Standard EPC recommendations frequently miss the point on these. A retrofit assessment models the building as it actually is — breathable construction, original fabric, unusual materials — and proposes measures that respect it.

What’s included

A PAS 2035 retrofit assessment covers four pillars:

1. Whole Dwelling Assessment. A full RdSAP-equivalent energy assessment, plus measured ventilation and detailed fabric record.
2. Occupancy assessment. Who lives there, how, and what their needs are. Bedrooms used, hours occupied, vulnerable occupants, fuel-poverty status. The right retrofit for a working family with two children is different from the right retrofit for a retired couple.
3. Condition and risk evaluation. Damp, ventilation, structural and material risks that need solving before insulation goes in. This is where most poorly-coordinated retrofit fails.
4. Improvement options & medium-term plan. A prioritised set of measures, sequenced sensibly, with the building physics worked through. Not a list of products.

What you’ll get

A bound PAS 2035 assessment report uploaded to the relevant TrustMark-recognised data warehouse and shared with you and your nominated Retrofit Coordinator. The document is the project’s reference for design and for any subsequent compliance audit.

How I work on traditionally-built homes

The default assumptions in standard energy assessment software are calibrated for post-1965 cavity-wall stock. Apply them unmodified to a 19th-century lime-mortared cottage and the recommendations come out wrong — sometimes dangerously so. For older buildings I model as-built U-values where the data supports it, flag breathability and condensation risk explicitly, and propose measures that have an evidence base in conservation-aware retrofit. Internal wall insulation, for instance, is rarely the right answer for a single-skin solid wall without a hygrothermal model behind it.

The wider team

I work with a small network of trusted Retrofit Coordinators, designers and installers across the South East. I’ll happily work alongside your existing team, or recommend one if you’re starting from scratch. No introducer fees either way.