Retrofit is becoming a serious income stream for contractors across Essex, Kent and London. General builders, roofing contractors, insulation installers, heating engineers, window companies and specialist energy-efficiency trades are all finding opportunities through ECO4, the legacy of the Great British Insulation Scheme, social housing decarbonisation work and local authority-led programmes.
That is positive news, but retrofit is not simply another form of refurbishment. The work is carried out on existing homes, often while people are living in them, and the intended performance of the property may depend on several different people getting their part right. A contractor may be installing insulation, but the wider outcome can also depend on the assessment, design, ventilation strategy, sequencing and handover.
This is why standard construction contractor insurance is not always built for the risk. The policy may provide a useful starting point, but it needs to reflect what the contractor has agreed to do, the role they are taking, the age and condition of the properties, and how long their obligations may continue.
The PAS 2035:2023 specification and guidance published by BSI places the emphasis on whole-dwelling assessment, design, installation, testing, handover and monitoring. In practical terms, that creates five insurance gaps contractors should consider before signing the next job.
1. The policy covers installation, but not the professional role behind it
The first gap appears when a contractor moves beyond physical installation.
A retrofit project may involve a Retrofit Assessor, Retrofit Coordinator, Retrofit Designer, Main Contractor and Retrofit Installer. In smaller businesses, one company or even one individual may take on several of these responsibilities. A general contractor might begin by installing loft insulation or replacement windows, then gradually become responsible for coordinating the wider package or advising on what measures should be used.
That is where the boundary between construction work and professional services becomes important.
Public liability insurance is designed mainly for injury to third parties or damage to third-party property. It is not normally intended to cover a claim alleging that a whole-house plan was unsuitable, a ventilation strategy was inadequate or a design decision caused financial loss without immediate physical damage.
Those exposures are more closely associated with professional indemnity insurance. A Retrofit Coordinator, designer or contractor accepting design-and-build responsibility may need PI cover that specifically recognises retrofit, energy-efficiency measures, moisture risk, ventilation and PAS 2035-related services.
The TrustMark Retrofit Coordinator Scheme Requirements illustrate why role clarity matters. They refer to the coordinator’s responsibility for risk assessment, improvement planning, records and project oversight, with insurance requirements applying to the professional role.
A contractor should not assume that having a standard general contractor liability insurance policy means every technical service is covered. If the contract says the business is responsible for the design, specification, coordination or performance of the retrofit package, the insurer needs to know that before the work starts.
2. An insurance-backed guarantee is not the same as a normal defects period
Retrofit work often comes with guarantees, warranties or insurance-backed guarantees connected to TrustMark, a product system, a funder or a client contract.
This is a very different obligation from promising to return during a short snagging period. A guarantee may require the contractor or a scheme to stand behind the work for 10, 15, 20 or even 25 years, depending on the measure and the terms involved. It may also respond if the contractor stops trading, fails to complete the work or cannot meet the guarantee obligation.
A guarantee is not the same thing as public liability insurance. It is not automatically covered by professional indemnity insurance either. PI generally responds to allegations of professional negligence, subject to the policy wording, while a guarantee may require the contractor to put right defective work even where there has been no separate claim for injury or third-party property damage.
The contractor also needs to check who is actually providing the protection. Is it the contractor, a manufacturer, a warranty provider or an insurance-backed scheme? What happens if the policy changes at renewal? Does the guarantee provider require particular certification, inspection records, installation methods or documentation?
These questions matter because a contractor can complete the work correctly but still have a problem if the guarantee has not been registered properly or the required evidence has not been retained.
Before accepting the contract, the business should identify every guarantee obligation, confirm the financial limits and duration, and ask the broker and relevant scheme provider how that obligation interacts with the insurance programme.
3. Existing Victorian and interwar homes create a building-condition exposure
New-build contractors are usually working from a planned design on a relatively known structure. Retrofit contractors are dealing with buildings that may have been altered, repaired or neglected several times over many decades.
Across Essex, Kent and London, that can mean Victorian terraces, early twentieth-century housing, interwar semis, converted flats and traditional properties with solid walls, suspended timber floors, ageing roofs or inconsistent previous improvements.
A survey may uncover poor pointing, leaking gutters, damp, movement, damaged roof coverings, defective cavity ties, blocked ventilation or historic alterations that are not shown in the original documents. If these issues are not identified before insulation or airtightness measures are installed, the retrofit may trap moisture or conceal a defect rather than resolve it.
PAS 2035 is designed to encourage a whole-dwelling approach, including assessment of the building’s condition, ventilation, construction, occupancy and existing defects. The standard also recognises that traditional buildings require particular care, and that some properties may need input from a structural engineer, building surveyor or conservation specialist.
From an insurance perspective, the key issue is the difference between a new defect caused by the contractor and a pre-existing condition that later becomes part of a dispute. A contractor may face allegations that the work caused damp or mould when the underlying problem was already present. Alternatively, the contractor may have failed to report a visible issue before proceeding.
This is why photographs, pre-start surveys, moisture readings, agreed exclusions, written instructions and records of remedial work are so important. They do not remove the risk, but they create evidence about the condition of the property and the decisions made before installation.
4. Working in occupied homes widens the public liability and care, custody and control risk
Retrofit work is often carried out in homes occupied by tenants, families, elderly residents or vulnerable people. Residents may remain in the property while floors are lifted, lofts are accessed, walls are opened and ventilation or heating systems are changed.
That creates more than a straightforward site safety risk. There may be dust, noise, restricted access, temporary loss of heating, damage to furnishings, contamination of personal belongings or an accident involving a resident who enters the working area.
Public liability insurance should be reviewed carefully for this environment. Contractors should also consider care, custody and control wording, because damage to property that is in the contractor’s possession or under their supervision may be excluded or restricted. The part of the building being worked on can be treated differently from unrelated third-party property.
For example, if an installer damages a client’s furniture while moving through the property, the policy response may not be the same as if a falling object damages a neighbouring home. If a wall, roof or floor being worked on is damaged, defective workmanship exclusions and “property being worked upon” provisions may become relevant.
The contractor should also understand responsibilities for resident communication, dust control, barriers, protection of floors and furniture, temporary works and emergency arrangements. These are operational matters, but they often influence how a liability claim is assessed.
Employers’ liability is also important. Employees may be exposed to respirable crystalline silica when drilling or cutting masonry, as well as dust from mineral wool, insulation boards, plaster and other retrofit materials. Loft work can create awkward access and confined working conditions, particularly in occupied properties where the work area may not be fully separated from the household.
5. The claim may arrive years after the work is hidden
Retrofit creates a long-tail risk because much of the work disappears behind dry lining, insulation, roof coverings, floors or other finishes.
A failure at a junction, an incorrectly installed vapour control layer, inadequate ventilation or a hidden moisture problem may not become obvious until several winters later. By then, the original contractor may have completed hundreds of similar properties, changed insurers or moved to a different business structure.
This creates questions about policy periods, notification, retroactive dates, run-off protection and how the insurer will handle a claim involving historic work. It also makes record retention essential. PAS 2035 includes detailed requirements around assessment information, design, inspection, testing, commissioning, handover and monitoring.
Contractors should not rely on a certificate of insurance alone. They need to understand whether their professional indemnity insurance is written on a claims-made basis, whether previous work is included, and whether cover remains available if the business stops carrying out retrofit work.
Product liability should also be considered where the contractor supplies or installs insulation systems, ventilation equipment, heating products, windows or other energy-efficiency products. Public liability may respond to resulting damage in some circumstances, but defective products and defective workmanship are separate issues and the exact wording matters.
Five checks before signing the next PAS 2035 job
Before agreeing to a retrofit contract in Essex, Kent or London, I recommend that contractors run these five checks:
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Confirm the role. Are you only installing, or are you also assessing, designing, coordinating, advising or accepting responsibility for the whole package?
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Map the contract obligations. Identify requirements for PAS 2030 installation, TrustMark registration, inspections, records, handover and insurance-backed guarantees.
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Review the property risk. Ask how pre-existing damp, structural defects, ventilation problems, traditional construction and resident vulnerability will be assessed and recorded.
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Test the policy wording. Check public liability, products liability, care, custody and control, pollution, work on existing structures, employers’ liability and professional indemnity.
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Plan for the long term. Confirm policy continuity, retroactive dates, notification requirements, document retention and the position if a claim emerges years after completion.
The right construction contractor insurance for retrofit should not be structured like cover for a new-build contractor. The work involves existing buildings, professional roles, occupied homes, technical performance and obligations that may continue for decades.
At Moyak Insurance Services, our general contractor insurance brokers take an individual approach because the details matter. A contractor working on insulation in a social housing programme does not face exactly the same risk as a contractor carrying out a one-off domestic refurbishment, even if both describe themselves as general builders.
If you are reviewing your construction contractor insurance before taking on PAS 2035 work, speak to a broker who will examine the actual scope rather than simply issue a standard certificate. The aim is not to buy the broadest policy at any price. It is to make sure the cover reflects the work you have agreed to stand behind.