Retrofit coordination is the process wrapper around a funded insulation job, and for most UK homeowners it arrives attached to the money rather than chosen deliberately. This guide sets out what a homeowner can verify for themselves, which claims about the framework are worth checking with the scheme before relying on them, and how the coordinator's decisions reach the external wall insulation specification that eventually goes on the wall.
One thing worth saying at the top, because it changes how the rest of this page reads. PAS 2035 is a purchased British Standards Institution document, and its clauses are not publicly readable. Renders World supplies materials rather than coordination services, so this guide stays on ground that can be checked against published government and scheme sources, and says plainly where a commonly repeated detail could not be confirmed. That boundary is more useful to a homeowner than a confident summary of a document neither of us can open.
What Retrofit Coordination Under PAS 2035 Covers, and Who Requires It
PAS 2035 is the publicly available specification for retrofitting dwellings published by BSI, and government-funded insulation work is delivered through the TrustMark quality scheme that sits around it. The framework's practical effect on a homeowner is that an installation becomes a documented project with an accountable trail behind it.
The parts of that trail which can be evidenced from published sources are narrower than most guides suggest, and they are worth separating cleanly from the parts that cannot.
- TrustMark is the Government Endorsed Quality Scheme covering work a consumer chooses to have carried out in or around their home, and a registered business has been vetted against required standards as a condition of that registration.
- Registration is held through a Scheme Provider, which may be a trade association, a certification body or a Competent Person Scheme. The provider a business is registered with is shown on its entry in the TrustMark business register, and it is the body that investigates if something goes wrong.
- Funded work runs through the schemes, not around them. The Energy Company Obligation covers insulation work for eligible households, with eligibility resting on benefits received and on the property's energy efficiency rating rather than on the installer's paperwork.
- Certification bodies oversee installer work and are one of the three bodies that may contact a homeowner during a quality check, alongside Ofgem and TrustMark.
The eligibility rules are the most concrete part of the funded route and the easiest to check before committing to anything. For a home you own, the property must have an energy efficiency rating of D, E, F or G, and the household must claim one of a defined list of benefits including Universal Credit, Pension Guarantee Credit, Pension Savings Credit, Income Support, income-based Jobseeker's Allowance, income-related Employment and Support Allowance, Child Benefit or Housing Benefit. Renting privately tightens the rating requirement to E, F or G and adds the owner's permission. The government guidance on the Energy Company Obligation carries the full position, and applications go through a local council or an energy supplier directly.
Details This Guide Could Not Confirm, and How to Check Them
Several specifics circulate widely about retrofit coordination — a particular diploma level for the coordinator, a named improvement-plan document, a fixed guarantee duration in years, and a rule on whether coordinator and installer may share a corporate parent. None of them could be verified from a published source during this revision, because the BSI and TrustMark pages that would carry them return only general scheme description to a reader who has not purchased the standard.
That is a reason to ask rather than a reason to worry, and the questions are short ones. Put them to the scheme provider named on the installer's TrustMark entry, in writing, before contracts are signed: which qualification the named coordinator holds, what the assessment and plan documents are called and when you will receive copies, what the guarantee covers and for how long, and what the relationship is between the coordinator and the installing company. A provider that answers those four in writing is demonstrating exactly the accountability the framework exists to create.
The Verification Pathway From First Quote to Sign-Off
The sequence below is ordered by when each check becomes possible rather than by importance, because a check run too late costs far more than the same check run early. Each step is something a homeowner can do without technical training.
- Confirm the business is registered before anything else. Look the trading entity up on the TrustMark register and note the Scheme Provider shown against it. Registration at the time the work is done is what later protection depends on, so a business registering mid-project is worth querying.
- Ask the four unconfirmed questions above in writing, addressed to the Scheme Provider rather than the salesperson. Written answers become part of your project file.
- Read the property assessment before agreeing a specification. Where it recommends ventilation work, sequence that alongside or ahead of the insulation rather than after it — moisture and ventilation are assessed together for good reason.
- Check the material specification names one manufacturer's system throughout, from adhesive and boards through mesh, primer and finish. Mixing manufacturers is possible, but it shifts responsibility for the assembly onto whoever specified it, because each manufacturer's documentation covers its own build-up.
- Photograph the wall at each stage. Adhesive coverage, fixing pattern, mesh laps and bead positions all become invisible once the finish goes on, and a dated photograph costs nothing at the time.
- Collect the completion paperwork as a set, including the updated energy assessment, the guarantee documentation and the scheme reference for the lodged job.
- Keep the file. It is what a future buyer's surveyor, a lender or a remediation programme will ask for, and reassembling it years later from memory is considerably harder than filing it now.
Step one deserves the emphasis it gets, because the published complaints rules turn on it. TrustMark cannot help where the business was not registered at the time of the work, where it has since ceased trading or lost registration, where the work completed more than six years ago in England, Wales and Northern Ireland or five in Scotland, or where the complaint is a financial or contractual matter. The Dispute Resolution Ombudsman route carries the same trading and registration conditions. Checking registration on day one is what keeps every later route open.
How the Assessment Reaches Your Material Specification
The assessment decides the insulation core, and the core then sets the adhesive, the fixing length and the finish above it. Three decisions account for most of the variation between UK domestic projects, and understanding the logic lets a homeowner read a specification sheet rather than simply receive one.
The core comes first. Genderka's EPS 032 Fasada Extra graphite boards are declared at λD 0.032 W/mK to EN 13163:2012+A1:2015, with a declared thermal resistance of 3.10 m²K/W at 100 mm read from the declared table rather than calculated from thickness. The same document declares the board reaction to fire class E, which describes the board as tested and says nothing about the finished rendered wall — a completed wall is assessed as a system, by the project's designer, under current Approved Document B guidance. Where a fire strategy calls for a non-combustible core instead, that conversation moves to the stone wool slabs and to the declaration of performance issued for the batch supplied.
Two practical constraints from the same technical sheet reach the programme directly. Mechanical fixing follows no earlier than 24 hours after the boards are bonded, which is a scheduling item rather than a preference. And because the boards are steel-grey, the manufacturer requires their surface to be protected from direct sunlight during storage and fixing, both brief and prolonged — a delivery-day decision about where the pallets stand. Adhesives are restricted to cement-based, polyurethane foam or water-dispersion bitumen products intended for graphite boards, with anything containing organic solvents excluded outright.
Key Takeaway: verify the installer's TrustMark registration and its Scheme Provider before contracts are signed, because the published complaints routes all depend on registration being live at the time of the work. Then get the coordinator's qualification, the document names, the guarantee terms and the coordinator-installer relationship confirmed in writing by that provider.
If the Work Is Already Done and You Have Concerns
There is a live government programme for exactly this situation, and it resolves the question for a large number of households without any dispute process at all. Quality issues have been identified with some solid wall insulation fitted through government schemes, including poor installation and failure to meet building regulations, which can lead to damp or mould.
- Who it covers: properties that had internal or external wall insulation fitted through the Great British Insulation Scheme or through ECO4 since April 2022. Ofgem is writing to all affected properties.
- External wall insulation: every property that had it installed will be offered a home check, quality checked by qualified professionals.
- Internal wall insulation: no action should be required, as an audit found fewer issues with it — though Ofgem can still be contacted with concerns.
- Already checked since January 2025: no further action is needed.
- If faults are found: the installer will be asked to fix them, and you should not be asked to pay any money for that work.
- Verifying who is contacting you: all organisations involved use your Unique Measure Reference, which appears in the Ofgem letter, and a freephone line is published for checking whether an approach is genuine.
The government guidance on poor quality wall insulation carries the contact routes, and a separate complaint outside that programme follows the three-stage TrustMark complaints process: the registered business first, then its Scheme Provider, then the Dispute Resolution Ombudsman where twelve weeks have passed or a final response has been received, and within twelve months of the initial complaint. The stages must run in order, since skipping one blocks escalation later. The homeowner inspection protocol for scheme-funded insulation covers what to look at on your own wall before making the call.
Next Step — Check the Register, Then Ask for the Assessment Separately
Two actions sit between a sales conversation and a project you can actually verify. Look the business up on the TrustMark register and note its Scheme Provider, then ask for the property assessment as a separately quoted first phase rather than a line folded into the installation contract. An assessment bought on its own can be read, questioned and acted on before the larger commitment is made, and it is the document from which every material decision afterwards follows.
When the specification is settled and the coordinator has named the system, Renders World can supply the components against it and confirm which manufacturer declaration covers each item, including the production plant a declaration was issued for. The material side of the decision — how graphite boards and stone wool slabs actually compare on declared figures — is argued out in the comparison of stone wool against graphite EPS, and the wider funding position is mapped in the guide to grant funding for external wall insulation.
Written by Mariusz Saja. Technically reviewed by Rafał Wyrzykowski. Last reviewed Aug 2026.
FAQ — Registration, Guarantees and Getting the Specification Right
Do I need retrofit coordination if I am paying privately rather than through a grant?
Coordination requirements attach to funded schemes, so a privately funded job is a different proposition. Whether commissioning coordination voluntarily is worthwhile depends on the property, and the assessment itself is usually the valuable part on complex or older buildings — it identifies moisture and ventilation risks before insulation traps them. Ask the scheme provider what a private-route job includes and what guarantee it attracts, since that varies and this guide could not verify a single national answer.
The specification says class E on the boards. Is that a problem?
Class E is declared for the graphite board as tested to EN 13163, and it describes that board rather than the wall it ends up in. A finished rendered wall is assessed as a complete system, and whether a class E core suits your building is a question for the project's designer against the building's height and use. It is a reasonable thing to ask the coordinator to explain in writing.
Can components from different manufacturers be mixed?
Physically yes, but each manufacturer's documentation covers its own build-up, so a mixed assembly moves responsibility onto whoever specified it. On funded or warranted work the cleaner route is a single manufacturer's system throughout. Stone wool in particular takes a dedicated adhesive rather than a polystyrene one, so a substitution at that layer is not a like-for-like swap.
How long should the whole process take?
This guide publishes no programme figure, because no source read this revision states one and an invented range would be the least useful thing here. Ask the coordinator for a written programme covering assessment, design, installation and sign-off, and treat any pre-remediation work such as damp treatment or ventilation upgrades as a phase in its own right rather than something absorbed into the installation weeks.
How long do I have to raise a complaint?
The published TrustMark position is that complaints about work completed more than six years ago cannot be considered in England, Wales and Northern Ireland, or five years in Scotland, reflecting the statutory limits under the Consumer Rights Act 2015. Reaching the Dispute Resolution Ombudsman additionally requires escalation within twelve months of your first complaint to the business. Both clocks reward acting early.
What if the installer has stopped trading?
The TrustMark complaints process cannot proceed against a business that has ceased trading or is no longer registered, and the Ombudsman applies the same limitation. The Ofgem-led home check programme is the separate route that does not depend on the installer's status, so for ECO4 or GBIS external wall insulation that programme is the one to pursue. Contact Ofgem with your Unique Measure Reference, or without it if the letter has gone astray.