PAS 2035 and PAS 2030 Explained: The Six Stages, Six Roles and Risk Pathways

One Standard, Two Documents

PAS 2035 is the British specification for how domestic retrofit should be delivered, and PAS 2030 is its companion standard for installers. The relationship confuses many candidates, but the simplest framing — used in the SHRA masterclass this post draws on — is that PAS 2030 is a chapter of the book, and the book’s title is PAS 2035. PAS 2030 existed first and governs installation; PAS 2035 wraps the whole project process around it, from defining outcomes through to monitoring.

Compliance is not optional for funded work. Government retrofit programmes such as the Social Housing Decarbonisation Fund require TrustMark registration, and TrustMark requires full compliance with PAS 2035. If you are delivering publicly funded retrofit, you are delivering it under this standard.

Did you know? PAS 2035 came out of the Each Home Counts review, commissioned after a wave of complaints about defective retrofit. Two of its key recommendations — a quality mark for the sector (TrustMark) and a code of practice underneath it (PAS 2035) — now anchor the entire funding landscape.

Why the Standard Exists

The case for PAS 2035 is written on the walls of failed projects: widespread damp, mould, condensation and rot caused by poor detailing, missing ventilation strategies and absent design. The frequently cited Preston-area scheme from 2013 — a £5 million external wall insulation project — has reportedly cost more in remediation than it did to deliver, with the human cost to residents harder still to quantify. Studies from that era found an alarming proportion of external wall insulation projects resulting in the most serious category of failure.

If those failure modes are new to you, our complete guide to damp, mould and condensation covers the building physics behind them, and our post on what installers must get right with external wall insulation looks at the workmanship side.

The Six Roles

PAS 2035 defines six roles, and exam questions love to test who does what:

• Retrofit Advisor — provides the householder with advice.
• Retrofit Assessor — carries out the dwelling assessment. Unless otherwise qualified, this role is limited to data collection; the assessor does not give advice.
• Retrofit Coordinator — the qualified specialist project manager with overall responsibility for delivery, protecting both the client’s and the public’s interest.
• Retrofit Designer — produces the design solution.
• Retrofit Installer — installs the measures under PAS 2030.
• Retrofit Evaluator — checks at the end that the project was delivered as intended.

The coordinator appears across almost every stage of the process and can fulfil several roles. One point worth committing to memory: the Retrofit Coordinator is appointed at stage one and stays involved to the end. Anyone suggesting a coordinator can be parachuted in at stage four or six is describing non-compliant practice.

Risk Pathways: A, B and C

Every project is triaged into a risk pathway before work is planned. The assessment considers the number of dwellings, the number of improvement measures per dwelling, the technical risk of those measures, the combination of measures, and the building’s construction and built form. The highest grade in any category sets the pathway for the whole project — all As with one C makes it a Path C project.

A useful analogy from the masterclass: Path A is the green nursery slope, Path B the blue slope, and Path C the red run — technically demanding and strictly for professionals.

The Six Stages of PAS 2035

Stage	What Happens	Key Output
1. Intended outcomes	Coordinator and client agree what the project should achieve	Documented, realistic outcomes
2. Risk assessment	Project triaged by dwellings, measures and construction	Risk pathway A, B or C
3. Dwelling assessment	Assessor collects data to the coordinator’s brief	Signed-off assessment for every dwelling
4. Planning and design	Options evaluated, plan and design produced	Improvement option evaluation, medium-term plan, design
5. Installation and handover	PAS 2030 installation, testing, commissioning	Compliant installed measures
6. Monitoring and evaluation	Outcomes checked against intentions	Escalating monitoring only if needed

A few points deserve expansion because they distinguish PAS 2035 from what came before.

The dwelling assessment is not an EPC survey. It is commissioned and briefed by the Retrofit Coordinator, goes far deeper than a typical EPC visit, and must cover every dwelling individually — every flat in a block, not one archetype assumed to represent the rest. The coordinator signs it off, and if data is missing, the assessor goes back until the job is done properly.

Planning and design has three sub-steps. The improvement option evaluation establishes the best combination and sequence of measures, modelling carbon cost-effectiveness, fuel costs and payback. The medium-term plan is a 20–30 year, property-specific route map recognising that most retrofits are delivered in stages as funding allows, taking account of household trigger points such as planned window replacement or changes in occupancy. Plans and assessments are lodged in the TrustMark data warehouse so they survive changes of tenancy and ownership.

The coordinator’s stage-five role is oversight, not site management. They check that what is installed matches the plan, approve any substitutions, and hold the installer to account. This is also where conflicts of interest bite: a coordinator employed by the installer needs carefully managed reporting lines.

Tip: For exam purposes, remember the escalation logic of stage six. Most well-delivered projects need only a basic occupant questionnaire; an independent coordinator investigation is step two, and full in-depth monitoring with sensors is the last resort — not the default.

Fabric First and Whole House — Debunking the Jargon

Two concepts recur throughout the standard and are routinely misunderstood. Fabric first means addressing insulation, solar gain and ventilation before building services and renewables — not ignoring heat pumps and solar panels, but sequencing them after the envelope. Whole house retrofit means treating fabric, services and renewables as one interacting system rather than isolated measures; it does not mean everything must be done in one deep hit.

The masterclass’s window example illustrates why this thinking matters: leave existing windows in their original position when adding external wall insulation and the thermographic image lights up with a thermal bridge that stores up heat loss, condensation and mould for later. Move the windows into the insulation layer — ideally by pairing EWI with planned window replacement — and the bridge disappears. These interactions are exactly what the Retrofit Coordinator Level 5 topic map organises into a revision plan.

How RetrofitReady Fits Into This

Everything above — the six stages, the six roles, risk pathways, dwelling assessment requirements and the fabric-first hierarchy — sits at the heart of the Level 5 Retrofit Coordinator qualification. RetrofitReady: Coordinator gives you 600 PAS 2035 questions across domestic retrofit, risk, fabric, services, ventilation, MTIP, and monitoring, so you can drill each stage of the process until the who-does-what-and-when logic is second nature. Use the explanations as revision notes: a wrong answer is only useful once you can say why the correct option is better.

The wider suite — over 1900 questions across 4 apps — covers the other PAS 2035 and PAS 2030 roles too, from Retrofit Assessor to Installer and DEA. Start with the free quizzes, or browse the full RetrofitReady app suite to match the app to your qualification route.