Overview
Sandwich panels are the modern answer to insulating a building envelope: two steel skins bonded to a rigid insulating core, delivering excellent thermal performance with very low weight and a finished appearance on both sides.
The core is what separates a good panel from a poor one. Delshine manufactures both polyurethane (PUR) and polyisocyanurate (PIR) cores. PUR is a rigid polyurethane foam with a good balance of insulation and cost. PIR is a modified polyurethane with a higher thermal performance and a much better fire behaviour, which is why it carries a B1 fire rating while PUR reaches B2.
Every panel we supply is a complete system: interlocking or hidden-lock joints, integrated drip grooves, factory-applied seams and coatings, ready for fast installation with no wet trade on site. This matters commercially, because the fastest way to reduce a project programme is to move the work into a controlled factory.
PU Sandwich Panel: Density 40±43 kg/m³ thermal conductivity ≤0.024 W/(m·K) B2 fire rating
Product identification
The identifiers below are the ones printed on the drum and quoted on the purchase order. Always order and dispatch by code, because the grade and the zinc or temperature variant cannot be inferred from the trade name alone.
| Product code | DSPU-50/200 |
|---|---|
| Trade name | PU Sandwich Panel |
| Category | Sandwich PU panels |
| System role | Insulated building envelope panel |
| Manufacturer description | Density 40±43 kg/m³ thermal conductivity ≤0.024 W/(m·K) B2 fire rating |
Where this product is used
- Insulated sandwich panel walls and ceilings for industrial buildings
- Cold storage and refrigerated warehouse construction
- Cleanroom and food-processing facility enclosures
- Roof and canopy systems for factories and warehouses
- Modular building and portable cabin construction
- Interior partition walls in workshops and plants
- Cold rooms, walk-in chillers and temperature-controlled stores
- Agricultural building and livestock housing envelopes
How it works in the coating system
A sandwich panel is a structural and insulating element manufactured in a controlled factory: two steel skins bonded to a rigid core, forming a complete envelope component delivered ready to install.
The core determines the performance. Polyurethane (PUR) core gives an economical panel with good insulation, while polyisocyanurate (PIR) core delivers better thermal conductivity and a superior fire rating. The joint profile, the steel gauge and the coating on the skins complete the specification.
Purpose in the system: A complete building envelope component in its own right, installed as wall, roof or ceiling.
Technical properties
The values below are the typical published range for this product family. The exact figures for your batch are confirmed on the batch certificate and the current technical data sheet.
| Role in the coating system | Factory-made structural insulated panel — wall, roof or ceiling |
|---|---|
| Volume solids | Not applicable (factory finished) |
| Mixing ratio by volume | Not applicable — no field mixing |
| Typical dry film thickness | 50–200 mm panel thickness; 0.5–0.7 mm steel skin |
| Theoretical coverage | Panels are supplied by the m²; joints and trims are supplied separately |
| Application methods | Mechanical fixing to a completed structural frame |
| Application temperature window | Installation from −30 °C to +50 °C |
| Suitable substrates | Steel or concrete structural frame |
| Finish / appearance | PPGI / PPGL steel skin, factory coated in RAL or standard colours |
| Principal resistance | Thermal insulation, load bearing, weather, fire |
| UV resistance | Factory-coated skin; check the coating warranty for the colour |
| Adhesion to prepared steel | Bonded core-to-skin, tested for delamination |
| Salt spray performance | Corrosion protection class C3–C4 on the folded edges |
| Chemical resistance | Not required; the core is closed-cell and does not absorb |
| Abrasion resistance | Impact resistant to the standard panel test |
| Flash point | Not applicable |
| Shelf life | Not applicable — deliver, install and seal promptly |
| Density | 40–50 kg/m³ core |
| Pack sizes | Effective width 950–1140 mm; length to order |
| Fire rating | B1 (PIR) · B2 (PUR) |
| Thermal conductivity | λ ≤ 0.020 W/(m·K) (PIR) · λ ≤ 0.024 W/(m·K) (PUR) |
Surface preparation
- Confirm the design load, span, panel width and fixing schedule against the project specification before ordering.
- Check that the structural frame is complete, plumb and dimensionally accurate — panels will not correct a crooked frame.
- Plan the lifting and handling sequence. Panels are light but large, and damaged corners are permanent.
- Verify that the roof has adequate drainage and that gutters and downpipes are installed to suit the panel profile.
- Ensure the site is clear and access is available for the installation crane or telehandler.
- Store panels flat, off the ground and out of the weather. Do not stack them face to face.
Application procedure
Install to a completed, plumb and dimensionally accurate structural frame. Panels will not correct a crooked structure.
Fix with the manufacturer's specified fasteners at the specified spacing and seal every joint with the compatible sealant.
Lift panels with clamps or suction lifters, never by dragging them across the ground, and secure them against wind before releasing the lifting equipment.
Mixing, ratio and induction time
Not applicable — panels are supplied finished and factory coated. No field mixing is involved.
Cure, recoat window and service readiness
Not applicable in the coating sense. Panels should be protected from the weather during the period between delivery and installation to prevent staining and corrosion of the exposed edges.
Coverage and thickness calculation
Panels are supplied in standard widths, typically 950-1140 mm effective, and a range of thicknesses from 50 to 200 mm. Specify thickness by the required thermal performance, not by habit.
Technical note. Coverage (m²/litre) = (volume solids × 10) / DFT (µm)
Worked example
| Specified DFT | 100 µm |
|---|---|
| Volume solids | 100 % |
| Theoretical coverage | 10.00 m²/litre |
| Total for the area | 100 m² → 1000.0 litres |
Advantages
- Excellent thermal insulation in a compact build-up, with a thermal conductivity of about 0.024 W/(m·K) for PUR and 0.020 W/(m·K) for PIR.
- PIR panels achieve a B1 fire rating, which is often the difference between passing and failing a building approval.
- Self-supporting panels remove the need for separate insulation and cladding layers, cutting labour and programme.
- Light weight means smaller structural sections and lower foundational loads.
- Factory-finished surfaces on both sides deliver a consistent, ready-to-finish appearance.
- Interlocking and hidden-lock joints create a continuous, weather-tight envelope with integrated drip grooves.
Limitations and precautions
- Panels cannot be modified on site without specialist tools — cutting and re-sealing is a specialist operation.
- Storage, handling and transport must be planned; edge damage during handling is the most common cause of rejection.
- Panel joints still need sealing, and penetrations need careful detail to preserve the envelope.
- Overhead crane access is usually required for installation.
- Thermal bridging at joints and fixings must be accounted for in the overall U-value calculation.
Storage and shelf life
- Store panels flat on timber bearers in a dry, ventilated area, protected from direct weather and standing water.
- Cover but allow ventilation so condensation cannot form between the skins.
- Do not stack panels on edge for long periods — the skins can deform under their own weight.
- Handle panels with lifting clamps or a suction lifter; never drag them across the ground.
- Keep the protective film on the outer skins until after installation is complete.
Safety, PPE and ventilation
- Wear cut-resistant gloves when handling panels — the steel edges are the main injury risk.
- Use eye protection when cutting or drilling panels.
- Secure panels against wind before releasing the lifting equipment; a panel is effectively a sail.
- Follow the crane or telehandler lifting plan and never stand under a suspended panel.
- Cut panels in a well-ventilated area and wear a dust mask when drilling or cutting the steel skins.
Quality control and inspection
- Check the panel thickness, core type and fire rating against the specification on delivery.
- Inspect for damage, edge deformation and skin defects before installation.
- Confirm the joint sealant and fixing system match the manufacturer's specification.
Pricing and how to order
Delshine quotes this product per square metre at a specified dry film thickness, or per drum/litre depending on the project. The material cost is usually the smallest part of the installed cost — surface preparation, access and application labour dominate. Send us the substrate, the service conditions and the required DFT and our technical team will return a full system recommendation with a firm price.
Sandwich panels are quoted per square metre of panel, at a stated thickness and with the core type, steel gauge, colour and joint type specified. The total installed cost depends heavily on the supporting structure, the number of openings and the crane access. When comparing quotations, check that the panel thickness, core and fire rating are identical — a lower price often means a thinner core.
Frequently asked questions
The questions below are the ones our technical team is asked most often about this product family.
What is the difference between PUR and PIR sandwich panels?
Both use a rigid foam core bonded between two steel skins. PIR (polyisocyanurate) has a modified core that gives better thermal conductivity — around 0.020 W/(m·K) versus 0.024 for PUR — and a significantly better fire rating, B1 rather than B2. PUR is the more economical choice where fire performance is not critical; PIR is specified where building regulations demand a higher fire classification.
What does the B1 and B2 fire rating mean?
It is the European building materials flammability classification. B1 means the material contributes very little to fire and does not ignite readily. B2 means it is normally flammable but will not sustain combustion over a small specimen for more than 20 seconds. For industrial buildings, hot works areas and high-rise projects, B1 is usually the minimum acceptable specification.
How long does a sandwich panel installation take?
Considerably faster than a conventional build. A 1,000 m² warehouse envelope with a purlin system can typically be enclosed in a few weeks, against several months for conventional masonry, insulation and cladding. The exact programme depends on panel width, crane access and whether windows and openings are pre-cut.
Can sandwich panels be used for cold storage?
Yes, and they are the standard choice. PIR panels with a B1 rating and a low thermal conductivity are used for cold rooms and refrigerated warehouses. The joints must be sealed with a compatible foam sealant and the design must avoid thermal bridges through fixings.
What is the maximum span of a sandwich panel?
It depends on the panel thickness, the core type and the design load. As a guide, 100 mm panels are normally used up to about 6 metres, 150 mm panels to around 7.5 metres, and 200 mm panels beyond that. These are indicative figures only — the panel manufacturer's load tables and your local code govern.
What coating is applied to sandwich panels?
The outer steel skins are supplied with a factory-applied coating system, normally a polyester or plastisol finish for weather resistance, with an inner liner suitable for the interior. Special finishes are available for food-processing or hygienic environments.
Related products
These products are normally used in the same system as the product described above.
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