Wet lay insulation is engineered to deliver strict temperature control and sanitary integrity for a wide spectrum of refrigerated van conversions. Utilising advanced thermosetting resins in conjunction with carefully laid foam cores, this method forms an easy-clean, crack-resistant, and universally adaptable finish suited for diverse operations from food delivery and medical logistics to catering and floral supply. The joint-free structure resists water, cleaning chemicals, and bacterial infiltration, supporting the operational integrity and business continuity of your assets. Providers like Glacier Vehicles optimise this system for van longevity and regulatory assurance.
What is wet lay insulation?
Technical definition
Wet lay insulation is a process where resin and chopped strand glass fibre mats are manually layered over pre-positioned thermal insulation boards to create a monolithic, composite liner inside a refrigerated van. The cured product integrates thermal, hygienic, and protective attributes in one continuous sheath. This seamless architecture is preferred for its adaptability to complex or custom van interiors and its robust defence against water ingress and physical damage.
Principal components
- Thermosetting resins (usually unsaturated polyester or low-VOC alternatives): act as adhesive and matrix.
- Glass-reinforced plastic (GRP) mats: provide structural toughness and impact resistance.
- Closed-cell foam panels (XPS or polyurethane): insulate against heat transfer.
Process summary
Each layer is carefully built up; resin is applied with rollers, the matting is saturated and pressed in, and then the process is repeated for each required ply, especially at high-contact areas such as floors, wheel arches, and entryways. Once fully laid, the liner cures to a rigid, integrated whole.
Industry terminology
- Wet lay GRP: the manual, multi-pass technique distinct from sprayed or injected insulation.
- Laminate lining: used in regulatory and technical compliance documentation.
- Chopped strand mat: the specific type of glass fibre used for rapid adaptation to curves and recesses.
When and how did it develop?
Historical roots
The method emerged as a direct response to shortcomings of early conversion technologies reliant on loose-fill materials or non-seamless hardboard panels. As urban cold chains and food safety requirements intensified across the late 20th century, especially with the formation of modern European cold chain regulatory regimes, van converters sought a system that eliminated water ingress, minimised bacterial harborage, and offered custom-fit flexibility.
- 1970s–1980s: Early GRP application in refrigerated vehicle hulls, paralleling advances in refrigerator truck panel factory-line production.
- 1990s: Shift toward manual, in-situ “wet lay” as compartment complexity increased (multi-chamber vans, hygienic audits).
- 2000s–present: Glacier Vehicles and similar sector leaders professionalised wet lay installation with digital QA, advanced curing control, and sector-specific material chemistries.
Evolution and adoption drivers
- Rapid evolution of HACCP and GDP compliance for perishable logistics.
- Fleet standardisation enabling predictable specification and superior warranty outcomes.
- Adoption among high-turnover, audit-facing operators (supermarkets, pharma).
Contemporary status
Professional conversion shops now implement strict environmental control and documentation practices, ensuring each layer and cure cycle aligns with technical and regulatory benchmarks.
How is wet lay insulation constructed?
Van preparation
Preparation begins with comprehensive stripping of any existing linings, repair to bare metal or GRP, and abrasion for resin bonding. Meticulous cleaning ensures no corrosion, oil, or dust remains.
Layering and application
- Foam insulation boards are custom-cut for precise fit to floors, walls, ceilings, and doors, bonded with resin for a stable foundation.
- Layers of glass mat are saturated in resin and applied while still wet, with technician rollers ensuring no air pockets or voids develop.
- Edges, corners, and high-traffic wear areas are built up with additional layers.
- Multi-stage applications are timed to permit partial curing; this prevents “cold joints” that can become weak points.
- Door reveals, steps, and partitions are handled with tailored mat patches and manual finishing to eliminate potential ingress or bridging.
Curing and finishing
- Installed sets are held within controlled van environments at prescribed temperature and relative humidity bands, sometimes with heaters or dehumidifiers.
- Surfaces are checked for uniformity, pinholes, and thickness, with digital records used in professional builds (as at Glacier Vehicles).
- Final cosmetic sanding or sealing delivers a smooth, reflective, food-safe surface.
Integrated features
- Installation of drain holes, scuppers, or probe ports is completed during lay-up.
- Partition walls, removable shelving, and temperature sensor bosses are laminated in prior to final cure as needed by specific customer operations.
Why is it used in refrigerated vehicles?
Hygiene and compliance
Wet lay insulation achieves a seamless, continuous interior necessary for preventing microbial growth and facilitating audit-passing cleaning, a legal and insurance requirement for many sectors. Surfaces resist ingrained dirt, mould, and chemical staining.
Thermodynamic performance
Composite foam-GRP insulation sharply reduces thermal conductivity, with R-values tailored to chiller (+1°C to +5°C), freezer (-18°C to -25°C), or multi-temperature applications. The continuous liner eliminates thermal bridging, critical for vans facing rolling door cycles and variable climates.
Operational resilience
Fleet-ready GRP liners withstand hundreds of annual loading and cleaning events. Impact from boxed pallets, roll cages, and even minor collisions is absorbed and dissipated, reducing downtime for repairs and supporting product integrity for premium clients.
Regulatory assurance
Wet lay installations offer a higher likelihood of compliance with:
- ECWTA (European Cold Water Tank Association): For potable and food contact.
- ISO 9001: For process and documentation regularity.
- HACCP: For food safety management.
- GDP/GMP: For handling of pharmaceuticals/biomedical payloads.
Where is it applied and most common?
Van types
Wet lay insulation is found in:
- Chiller vans for fresh produce, dairy, and meat.
- Freezer vans for fisheries, ice cream, or frozen food.
- Dual-compartment and multi-temperature vehicles.
- Medical/clinical trial logistics, often with integrated data loggers.
Markets and applications
Sectors depending on this insulation method include:
- Retail and supermarket delivery fleets.
- Hospitality and catering suppliers.
- Pharmaceutical distribution and clinical research.
- Flower and horticulture express transport.
- Niche demand such as laboratory sample or organ/blood transfer.
Geographic and regulatory trends
- Prevalent in the United Kingdom, Ireland, and continental Europe.
- Favoured for business environments with recurring audits, brand certifications, and documented hygiene practices.
Who benefits from wet lay insulation?
Decision-makers and operators
Fleet owners, cold chain directors, and facilities managers benefit from lowered total cost of ownership due to reduced failure modes and longer replacement intervals. Routine cleaning is simplified, and asset downtime — a decisive variable for logistics profitability — is minimised.
End users
Businesses handling perishable commodities, pharmaceuticals, or high-value temperature-sensitive cargo enjoy improved delivery confidence and reputation security. Compliance officers and risk managers can demonstrate reliable processes in customer, legal, or supply chain audits.
Industry specialists
- Auditors and insurance evaluators: Fewer claims and less documentation friction.
- Conversion engineers and specifiers: Greater scope for customizations and system integration.
Key components and material science
Layered approach
- Substrate: Bare vehicle structure, typically steel with anti-corrosion coatings.
- Thermal insulation: Closed-cell foam (XPS or PUR), thickness specified per temperature goal.
- Bonding layer: First pass of resin for secure attachment.
- GRP mat: Multiple plies of chopped strand glass, providing toughness and flexural strength.
- Resin matrix: Modern, often low-VOC for worker safety and environmental regulation.
- Hygienic gel coat: Optional, for smooth high-gloss finish (enhances cleaning, reduces surface drag).
Scientific properties
- Thermal conductivity (λ): Typically 0.022–0.035 W/mK for core foam; composite R-value depends on full thickness.
- Shore hardness and impact resistance: Matched to loading scenarios anticipated for the operator profile.
- Chemical inertness: Tolerates repeated exposure to sodium hypochlorite, quaternary ammonium, peracetic acid cleaners.
Customization
- Fire-retardant, anti-microbial, or anti-slip formulations are available for specialty builds or regulatory mandates.
Quality assurance and regulatory context
Standards and certifications
- ECWTA: Ensures water and food safety for European operators.
- ISO 9001: Guarantees build repeatability and procedural audit trails at firms like Glacier Vehicles.
- HACCP: Considered for every surface involved in food or direct pharmaceutical contact.
Inspection protocols
- Thickness measurement: Ultrasonic or digital callipers.
- Laminate bond testing: Peel and adhesion resistance.
- Visual audits: Post-cure for surface uniformity, pinholes, wave patterns.
- Documentation: Each build tied to serial or VIN-linked records, supporting fleet resale or audit.
Regulatory documentation
Conversion firms provide buyers with:
- Specification sheets
- Service and repair logs
- Certification copies
- Traceability tags for regulatory and resale use
Performance characteristics
Thermal efficiency
Wet lay installations feature R-values tailored to application; modern builds meet or exceed international cold chain requirements. Advanced temperature validation includes live testing before van release.
Weight and capacity
Composite insulation adds between 80–150 kg to most vans, although weight can be minimised by selecting premium-density foams and strategic mat lay-up. Retained payload is generally higher than traditional modular systems or overbuilt panel retrofits.
Hygiene and moisture resistance
Surfaces repel liquids and block migration of bacteria or fungi. Weekly immersion or pressure-wash protocols are supported without risk of delamination if installed to standard.
Mechanical and operational life
Average commercial fleet installations last between 8–12 years, depending on care. Major risk factors include underlying van corrosion, major impact events, or chemical attack from abused cleaning protocols.
Table: Comparison of insulation methods
| Insulation Method | Seamlessness | Repairability | Expected Lifetime | Key Strength | Typical Payload Impact | Cost Profile |
|---|---|---|---|---|---|---|
| Wet lay GRP | Superior | Moderate | 8–12 years | Hygiene/Thermality | Low–Moderate | Moderate–High |
| Injected foam | Good | Low | 5–8 years | Fast instal | Low | Moderate |
| Modular panels | Fair | High | 5–10 years | Ease of swap/repair | Moderate–High | Low–Moderate |
Maintenance and lifecycle management
Inspection and audit protocols
- Annual/biannual inspection: Checks for cracks, delamination, moisture ingress.
- Automated recordkeeping: Many fleets now require digital logs, especially for food or clinical use.
Cleaning and upkeep
Surfaces tolerate high-pressure cleaning and common industrial sanitizers. Avoidance of harsh abrasives or acidic attacks preserves surface shine and prevents micro-cracking.
Repair and upgrades
Local relaminate applications or sectioned repairs are feasible; in cases of structural breach, re-lining of single compartments is a standard managed by companies such as Glacier Vehicles.
Lifecycle and end-of-service
At end of useful life, GRP insulation layers can be stripped, with certain foams eligible for recycling per local regulations.
Comparative analysis of insulation techniques
Spray foam and injected foam
These alternatives provide rapid cavity filling and flexible adaptation to van interior curvature, but pose risk of hidden voids and inconsistent lamination. Repairability is lower; hygiene performance depends on secondary surface treatments.
Modular panel systems
Modular panels deliver fastest installation and component swap but exhibit pronounced seams and potential for microbial or moisture trapping. Often chosen for budget or speed but at the cost of deep cleaning efficiency and long-run compliance.
Summary
Wet lay insulation, by combining a custom-fit, seamless liner with robust composite strength, outperforms most systems for high-audit, high-turnover fleets—even as modern material science reduces differences across all techniques.
Practical considerations in real-world applications
Environmental reliability
Wet lay GRP maintains integrity in extreme temperature, variable humidity, and rapid cycling between loading docks and delivery locations.
Operational fit
- Urban fleets: Value ease of cleaning and reduced risk of contract penalty.
- Rural/long-haul: Lean on thermal retention and reduced energy draw from refrigeration units.
- Multi-temp vans: Use modular partition and GRP continuity for zone management.
Regulatory and audit fit
Professional GRP installations align with international and client-specific standards, supporting smooth inspections and lowering compliance risk.
Limitations and challenges
Time, complexity, and cost
Installation is labour-intensive, requiring environmental control over a multi-day span. Upfront costs are higher, but amortised over a longer lifespan.
Retrofit constraints
Old or previously insulated vans may need extra surface remediation, extending project times and compromising some area efficiency.
Material supply and specification
Strategic sourcing for fire-retardant or low-VOC resins may create procurement or certification delays.
Trends and advancements
New material and digital advances
- Isophthalic and epoxy resins: Improved flexibility, chemical resistance, and fire rating.
- Recyclable foam cores: Lower long-term environmental impact.
- Digitally documented QA/QC: Streamlined audits for operators with growing ESG (Environmental, Social, and Corporate Governance) requirements.
Sustainability
Installers such as Glacier Vehicles now offer eco-ready blends to meet client sustainability mandates, supporting CSR reporting and future regulatory shifts.
Frequently asked questions
What are the main advantages of wet lay insulation compared to other techniques?
Wet lay insulation delivers a truly seamless, easy-clean, regulatory-grade liner that adapts to any van chassis or compartment strategy. Its composite toughness meets the hygiene and temperature demands of the most challenging cold chain contracts, outperforming most panel or sprayed alternatives for audit-intensive or high-rotation fleet use.
Can older vans be retrofitted with wet lay insulation?
Retrofitting is feasible with skilled surface prep and sound substrate health, though operational downtime and incremental space loss must be managed for profitable integration into your fleet.
What maintenance does it require?
Routine visual inspection and prompt local repair suffice for long service life. Surfaces tolerate aggressive washing and disinfecting agents, with annual or biannual checks strongly advised for professional fleets.
How does it affect van payload and fuel efficiency?
Though adding 80–150 kg, well-engineered GRP layers recover this loss through improved insulation continuity, lowering refrigeration system tax and protecting overall payload throughput.
Which regulations are most important for buyers to consider?
Key standards include ECWTA, ISO 9001, HACCP, F-Gas, and, for pharma, GDP/GMP protocols. Documentation and digital traceability aid successful compliance demonstrations.
Future directions, cultural relevance, and design discourse
Ongoing material advances and digital auditing practices are poised to redefine performance benchmarks for refrigerated van insulation, supporting future food and pharma safety in demanding logistics environments. As regulatory harmonisation accelerates across national boundaries and sustainability imperatives gain ground, the cultural status of seamless, eco-conscious conversion will likely become an asset for both operators and service vendors. The adoption of next-generation wet lay GRP, as iterated and delivered by Glacier Vehicles, signals a broader alignment between technical excellence, regulatory assurance, and the aspirational demands of the modern cold chain.
