The effectiveness of refrigerated transport hinges on consistent temperature control, robust hygiene barriers, and adaptability to regulatory demands. Wet lay insulation combines glass-reinforced plastic (GRP) application, specialised foam, and skilled hand-laying processes to produce a continuous, food-safe shell fitted to the van’s unique architecture. Industry practitioners, including fleet procurement managers and technical vehicle converters, routinely select wet lay insulation to maximise operational efficiency, ensure load integrity, and optimise fleet value.
What is wet lay insulation?
Wet lay insulation is defined by the manual application of resin-infused fibreglass matting over a rigid foam substrate within the van’s cargo compartment. Layers of mat and resin are custom-shaped and applied, then chemically cured to create a seamless, monolithic barrier. The result is an integrated, non-porous shell characterised by minimal thermal bridging and superior cleanability. Wet lay is distinct from modular panel or spray foam systems, offering advantages in coverage, adaptability to irregular shapes, and resistance to joint failure or microbial buildup.
Defining features
- Seamless, continuous shell construction
- Tailored fit to any van geometry
- Unified thermal and hygienic barrier
- Hand-laminated GRP and high-performance foams
Why is insulation important in refrigerated transport?
Insulation establishes the thermal boundary between external temperatures and interior cargo space, enabling reliable storage and transport of perishable goods. An inadequately insulated van exposes sensitive cargo to temperature excursions, risking spoilage, safety breaches, and regulatory failure. Modern standards for food, pharmaceutical, and biological samples require vehicles capable of maintaining specific temperature zones—demands that place insulation method and quality at the heart of fleet selection.
Role in cold chain logistics
- Maintains temperature consistency when doors are opened and closed
- Reduces refrigeration energy consumption and operational costs
- Lowers risk of insurance claims linked to temperature deviation
- Helps your company pass third-party inspections and protect your brand’s credibility
How does the wet lay process work?
Constructing a wet lay lining comprises sequential, controlled steps by trained specialists. Proper preparation and expert application distinguish high-performing wet lay conversions—elements that shape reliability, compliance, and hygiene outcomes for your business.
Installation stages
-
Preparation
Cargo area is stripped of prior linings, contaminants are removed, and the metal shell is inspected and repaired as needed, establishing sound adhesion and structural integrity. -
Foam Board Placement
Insulation boards—often extruded polystyrene (XPS) or polyurethane (PU)—are custom-cut and fixed to every interior surface, maximising thermal resistance while accommodating van features like wheel arches. -
Resin Mixing
Resin systems (typically food-approved polyester or isophthalic variants) are catalysed and combined with antimicrobial additives. Glass fibre matting is measured and tailored for a continuous coverage. -
Hand Laying and Lamination
The technician hand-laminates the wetted matting across all surfaces, blending layers and reinforcing high-wear areas as needed. The skill of this stage determines the absence of air voids, cold bridges, or surface irregularities. -
Curing
Controlled curing allows chemical cross-linking, ensuring structural hardness and durability. Key parameters—ambient temperature, humidity, and time—are monitored closely. -
Finishing and Quality Checks
Once hardened, the surface is sanded and visually inspected for seamlessness. Tap testing or ultrasonic assessment identifies voids; thermal imaging may confirm insulation continuity.
Advantages in application
- Supports integration with partition systems, electrical infrastructure, and bespoke cargo tracks
- Compatible with after-market refrigeration units (including GAH) and custom access points
- Allows for single or multi-compartment builds in bespoke commercial models
What materials and technologies are involved?
Wet lay insulation is engineered using advanced composite materials and precision application techniques. The blend of foam core, reinforcement, and chemical matrix determines the system’s insulation value, cleanliness, and mechanical resilience.
Core substrates
- Polyurethane (PU) foam: Delivers high R-value and compressive strength for freezer and chiller applications.
- Extruded polystyrene (XPS): Favoured for its low moisture absorption and lightweight structure.
Structural reinforcement
- Chopped strand matting: Laminated in layers for durability; offers resistance to impacts and flexural stress.
- Woven glass fabric: Sometimes specified for superior mechanical performance or custom upgrades.
Matrix resins and additives
- Polyester resin: Industry standard for food-safe interiors, available with anti-microbial treatment.
- Epoxy resin: Used for specialist applications requiring chemical or extreme-temperature resistance.
- Catalysts and accelerators: Ensure correct curing and in-service strength.
Performance features
- Thermal resistance: Measured by R-value; typical thickness ranges from 50 mm (chiller) to 100 mm or more (deep-freeze).
- Water and vapour impermeability: Maintains structural hygiene and prevents mould growth.
- Non-porous hygiene finish: Supports compliance with ATP, HACCP, and ECWTA standards.
| Property | Wet Lay System | Panel/Modular System |
|---|---|---|
| Seamless Finish | Yes | No |
| Insulation Range | 50–150 mm (customizable) | 50–100 mm (fixed) |
| Cleanability | Excellent | Moderate |
| Retrofit Capability | High | Low–Moderate |
| Longevity | 8–12+ years | 5–8 years |
Who uses wet lay insulation?
Wet lay insulated vans are chosen by organisations whose core operations depend on reliable, regulatory-grade temperature control and hygiene. These stakeholders include:
- Large supermarket and retail logistics fleets: Often with stringent multi-compartment, multi-temperature specifications.
- Specialist clinical, pharmaceutical, and laboratory transport: Need for sterile, easily sanitised interiors aligned with GDP (Good Distribution Practice).
- Event caterers, food wholesalers, and chain restaurants: Rely on extended asset lifespan and certified audit trails.
- Microfleet owners and operators: Value long-term serviceability and proven compliance.
- Fleet procurement directors: Consider wet lay for both new acquisitions and retrofitting existing assets.
Collaborating with conversion partners such as Glacier Vehicles helps your company align sector needs with technical solutions, warranty coverages, and aftercare.
Where is this method applied?
Wet lay insulation spans a broad array of temperature-controlled van types and sector uses—including:
Application typologies
- Chiller vans: Typically serving +2 °C to +8 °C, optimised for perishables, dairy, and fresh produce.
- Freezer vans: Designed for temperatures as low as -25 °C, requiring advanced insulation and resin chemistry.
- Split-compartment vans: Utilised by home delivery, supermarket, and catering fleets requiring distinct temperature zones within a single unit.
- Van retrofits and upgrades: Enables older assets to meet new compliance benchmarks without total replacement.
- Custom sector builds: Food delivery, medical logistics, floral, laboratory sample handling, and event services all specifying wet lay for hygiene and compliance.
Geographical and regulatory context
Van insulation approaches may vary slightly depending on local temperature, humidity, and compliance standards, but the core wet lay process remains globally consistent and increasingly favoured in regulated markets such as the UK and EU.
When is wet lay insulation chosen over other systems?
The decision to use wet lay insulation is driven by several converging factors:
- Complex van geometry: When a modular approach fails to provide full coverage or seamlessness.
- Heightened hygiene and audit demands: For companies operating under regulated regimes or supplying premium clientele.
- Retrofit efficiency: As a solution to restore or upgrade existing linings without disrupting the vehicle’s entire operation.
- Multi-use versatility: For fleets catering to a rotating variety of cargoes, each with different hygiene or temperature mandates.
Decision-makers may weigh up-front investment against projected compliance savings, energy efficiency gains, and resale premiums—calculus that increasingly makes wet lay systems the industry preference for demanding applications.
Why do regulatory bodies require high-performance insulation?
Regulatory compliance is integral to the transport of foodstuffs and temperature-sensitive goods, not merely as a matter of law but as a gateway to premium contracts and supply chain trust.
Regulatory standards
- ATP (Accord Transport Perishables): Requires documented temperature performance and insulation thickness.
- ECWTA (European Cold Water Tank Association): Sets technical benchmarks for materials and composite performance.
- HACCP (Hazard Analysis and Critical Control Point): Mandates hygienic, easily sanitised interiors for direct food contact.
Role of conversion documentation
Insulation compliance is evidenced by certificates, inspection reports, and sometimes live temperature logging. These artefacts must be produced during audits (scheduled or surprise), supplier due diligence, and insurance reviews. Providers such as Glacier Vehicles integrate compliance at build, handover, and throughout warranty/service cycles.
How is quality maintained and verified?
Quality assurance in wet lay-insulated vans is a multi-stage discipline, incorporating both materials engineering and craftsmanship:
Key assurance measures
- Curing protocol validation: Technicians strictly monitor temperature, humidity, and time during chemical curing phases.
- In-process quality checks: Each insulation and resin layer is visually evaluated, with random tap and ultrasonic checks to detect voids or delamination.
- Final inspection: Surfaces must be visually seamless and pass resistance, tensile, and cleaning trials.
- Maintenance and documentation: Operators receive digital and physical QA portfolios, outlining the maintenance plan, warranty, and compliance records.
Routine checks, rapid repair response, and lifecycle management—all hallmarks of Glacier Vehicles service—sustain reliability for fleets and asset managers.
What are the performance, durability, and maintenance characteristics?
Wet lay insulation maintains performance standards beyond initial delivery, directly influencing both cost of ownership and operational continuity.
Key characteristics
- Thermal efficiency: Maintains target temperature profiles with minimised energy loss.
- Longevity: Seamless linings typically match the expected service life of new vans and can extend functional lifespan in retrofits.
- Repairability: Damaged areas can be excised and relaminated, protecting the asset from unnecessary downtime.
- Cleanability: Food-grade resin and mat surfaces are compatible with a wide range of cleaning solutions, satisfying audit and client demands.
Table: Performance comparison
| Attribute | Wet Lay | Panels | Spray Foam |
|---|---|---|---|
| Seamless Finish | Yes | No | Partial |
| Audit Readiness | High | Moderate | Moderate |
| Maintenance Cost | Low-Moderate | Variable | Variable |
| Service Life (years) | 8–12+ | 5–8 | 5–7 |
What are the strengths and limitations of this approach?
Strengths
- Full customizability: Ability to match any van’s internal shape; accommodates fixtures, partitions, and variable cargo.
- Hygiene and compliance: Superior for food/pharma; eliminates contamination risks from seams and joints.
- Lifecycle value: Extended operational lifespan, reduced maintenance frequency, and clear documentation aid asset resale value.
- Regulatory alignment: Simplifies process of passing inspections, securing contracts, and reducing operational liabilities.
Limitations
- Skill dependency: Consistent quality requires experienced technicians; defects are harder to rectify than plug-and-play panel swaps.
- Installation time: Van downtime is marginally increased compared to modular insert equivalents.
- Upfront investment: Higher costs are often offset by operational savings and enhanced compliance but remain a gating factor for smaller fleets.
What are the most recent trends and materials innovations?
Recent advances are pushing wet lay insulation beyond legacy practice, transforming both sustainability and value.
Trends
- Eco-smart materials: Bio-based and recycled resin systems, non-toxic additives, and lower-emission manufacturing reduce environmental impact and help your company meet green supply chain commitments.
- Quality control with data integration: Installers increasingly employ thermal imaging and digital QA recordkeeping, providing transparent compliance records to asset owners and auditors.
- Segmented and hybrid compartment solutions: Flexible builds enable sophisticated fleet-wide management of cold chain needs, particularly for rapidly evolving last-mile delivery models.
- Post-instal telematics integration: With ongoing compliance monitoring, fleet managers gain operational intelligence for preventative maintenance and audit readiness.
Specialists like Glacier Vehicles are rapidly adopting these advancements, embedding them into product and service offerings for forward-looking clients.
Frequently asked questions
Can wet lay insulation be repaired or upgraded after years of service?
Wet lay insulation is repairable through targeted section replacement, using compatible resins and reinforcement for a seamless repair. Retrofits extend vehicle asset life, delay full replacement, and help your organisation adapt to new compliance benchmarks at a lower capital cost.
How does wet lay insulation impact hygiene and biosecurity in refrigerated distribution?
A continuous, non-porous GRP shell reduces bacteria harborage zones and supports rapid, effective cleaning. Antimicrobial additives align with the needs of regulated fleet buyers, ensuring internal audit traceability.
What are the main cost drivers for wet lay conversions compared to other methods?
Core cost drivers are material specification, wall/floor thickness, cargo volume, and required customization. High-quality wet lay installations tend to carry a premium on the initial invoice but deliver superior ROI via energy savings, reliability, and simplified end-of-life asset valuation.
How is regulatory compliance and certification handled in wet lay insulated vans?
Certification includes in-process QA documentation, material traceability, physical thickness graphs, and operational readiness inspection. Maintaining these records ensures rapid contract response and efficient insurance validation.
How does wet lay insulation affect thermal performance in extreme environments?
Performance is sustained across operating ranges by adapting material thickness and resin type to the climate and cargo use case. Regular maintenance and QA records are the backbone of reliability in harsh or variable conditions.
What should be considered before choosing wet lay insulation for a new or retrofitted fleet vehicle?
Assess your operational priorities, regulatory landscape, service expectations, and lifetime cost profile. Selecting a trusted, compliant provider such as Glacier Vehicles ensures support for every stage: specification, installation, documentation, aftercare, and audit response.
Future directions, cultural relevance, and design discourse
The future of wet lay insulation in refrigerated van conversions is closely linked to shifts in global food safety protocols, sustainability priorities, and fleet standards. Ongoing refinement in composite science and embedded digital reporting are poised to reshape expectations for compliance, operational efficiency, and asset lifespan. Cultural attitudes increasingly favour companies that can demonstrate both environmental and regulatory stewardship—a trend amplified by market demand for transparent, hygienic cold chain solutions. In this dynamic landscape, the combination of advanced materials, documentable process control, and seamless technical support reinforces your organisation’s operational agility and brand reputation. Continuous improvement, responsive aftercare, and sustainability initiatives from providers such as Glacier Vehicles remain crucial to market leadership in temperature-controlled transport.
