An insulated sandwich panel is a modular industrial material made of 2 galvanised or stainless steel facings enclosing an EPS, PU or Rockwool insulating core. The tongue-and-groove edge profile allows fast, tight assembly with no welding. How to construct the panel done correctly determines the insulating performance, durability and service life of the whole wall system.
This article brings together the process for installing insulated panels for partitions and ceilings: the 3 panel types (EPS, PU, Rockwool), the aluminium accessories (U28×50 mm, V, T and H sections), the 7-step process from survey to handover, the technical standards (joint tolerance ≤1 mm, wall plumb ≤2 mm/2 m), and the 6 common errors to avoid. The content draws on Tân Long's practical experience of more than 100 cold store and factory projects over 20 years.
What is an insulated panel? Construction and how the insulation works
An insulated panel is a modular material made of 2 steel facings (galvanised or 304 stainless) enclosing an EPS, PU or Rockwool insulating core. The tongue-and-groove profile lets the panels lock together tightly with no welding. It is the principal material for partitions and ceilings in factories, cold storage, cleanrooms and industrial buildings.
Unlike brick or plasterboard walls, insulated panels are dry construction. Installation needs no rendering and no drying time, and is 3–5 times faster than traditional brickwork. On the insulation principle, a PU core has a thermal conductivity of 0.022 W/mK and EPS 0.034 W/mK — the lower the figure, the better the thermal performance. The steel facing protects the core from impact, moisture and the environment.
Panels fall into 3 main groups according to the insulating core, each with different technical properties.
Panel types: EPS, PU and Rockwool compared on properties and applications
Insulated panels come in 3 main types by core: EPS (density 15–25 kg/m³ / 0.94–1.56 lb/ft³), PU (density 38–42 kg/m³ / 2.37–2.62 lb/ft³) and Rockwool (density 80–120 kg/m³ / 5–7.5 lb/ft³). Each suits a different class of building. The table below compares the main technical properties:
| Criteria | EPS Panel | PU Panel | Rockwool Panel | Unit |
| Density | 15–25 | 38–42 | 80–120 | kg/m³ |
| Thermal conductivity | 0.034 | 0.022 | 0.038 | W/mK |
| Common thicknesses | 50 / 75 / 100 | 50–200 | 50 / 75 / 100 | mm |
| Fire resistance | No | Fire retardant | Withstands 1,000°C | — |
| Life expectancy | 10–15 | 20–25 | 20–25 | years |
| Relative cost | Lowest | 30–40% higher than EPS | Highest | — |
EPS Panel (Expanded Polystyrene)
EPS panels suit buildings that do not require deep insulation: office partitions, ordinary factories, processing areas without temperature control. Their advantages are light weight and low cost. EPS is not suitable for cold stores below −18°C (0°F), however, as it does not insulate effectively at deep sub-zero temperatures.
PU (Polyurethane) Panel
PU panels have the lowest thermal conductivity of the three (0.022 W/mK), suiting cold stores, cool storage, cleanrooms and the food industry. At the same thickness, PU insulates 35–40% better than EPS. On cold store projects, the Tân Long team uses 40 kg/m³ PU panels as standard for most wall and ceiling systems.
Rockwool (mineral wool) panels
Rockwool panels withstand up to 1,000°C (1,832°F), suiting factories with demanding fire protection requirements and heavy industrial sites. Their drawbacks are that they are heavier than EPS and PU, the most expensive of the three, and prone to absorbing moisture unless properly sealed.
Once the panel type is chosen, the next step is preparing the accessories and tools.
Materials, accessories and tools to prepare before installing panels
Panel installation needs 2 main groups of items: connecting accessories (U, V/L, T and H sections and corner trims) and installation tools (screw gun, laser level, disc cutter, silicone gun). The quality of the accessories determines the rigidity, airtightness and service life of the wall system.
| Fitting | Function | Suggested size | Material |
| Thanh U | Connects the panel to floor/ceiling | U28×50×28 mm, 1.0 mm (0.04 in) thick | Aluminium or stainless steel |
| V/L scale | Corners and square wall junctions | V38×38mm, L38×75mm | Aluminium |
| Thanh H | Joins 2 panels | H50mm | Aluminium |
| Thanh T | Suspends the ceiling panels | 1.3 mm (0.05 in) thick | Aluminium or stainless steel |
| Corner trim | Finishes square corners | 1.1 mm thick | Aluminium |
For tools, the installation team needs an impact driver, a laser level, a low-speed circular saw, a caulking gun, aluminium ladders, a chalk line, expansion bolts and self-tapping screws. On cold store projects the Tân Long team always uses aluminium U sections at least 1.0 mm thick — thinner sections (0.8 mm) distort readily under the load of panels 100 mm and thicker.
With the materials in place, the next stage is installation, following the 7 steps in order.
How to install panels: 7 steps from preparation to handover
Installing insulated panels involves 7 steps: survey the site, fix the aluminium framing, erect the panel walls and engage the joints, install the ceiling panels, cut and fit doors and vents, seal with silicone and fit the corner trims, and inspect and hand over. The order of work directly affects the airtightness and service life of the wall system.
Step 1: survey the site and set out the installation positions
Before work begins, the technician measures the site with a laser level and marks the exact positions, with a permitted tolerance of ≤3 mm/2 m (≤0.12 inches/6.5 feet). This includes checking the floor for level, establishing the framing fixing positions and setting out a reference plane with a chalk line or laser. This step determines how true the whole wall system will be — an error at the setting-out stage multiplies many times over once the wall goes up.
Step 2: fix the aluminium framing — U, V and T sections
Aluminium U sections (U28×50 mm, 1.0–1.2 mm / 0.04–0.05 inches thick) are fixed to the floor and ceiling with expansion bolts at 300–400 mm (12–16 inch) centres. Once the framing is fixed, the installers run silicone into the gap between the U section and the floor or ceiling surface to block moisture ingress. This is the foundation step that determines how solid the whole wall system will be.
On site, the Tân Long team checks the U section for level with a laser before driving the fixing screws — a 2 mm error in the framing becomes 5 mm at the top of a 3 m wall.
Step 3: erect the panel walls and engage the tongue-and-groove joints
Panels are erected starting from a corner, seated in the U section channel. They lock together through the tongue-and-groove profile with a permitted joint gap of ≤1 mm (0.04 inches). The installers fix them with self-tapping screws and V/L clamps at the corners. Where something will be hung (racking, a cooling unit), the technician reinforces the panel with box steel embedded during manufacture.
Use panels cut to size from the design drawings rather than cutting on site. This reduces material waste, saves time and avoids denting the steel facing while cutting.
Step 4: install the ceiling panels and the hanger system
Aluminium T sections (1.3 mm thick) and rod hangers are fixed to the purlins or roof steelwork at 1,000–1,200 mm (39–47 inch) centres. Ceiling panels are laid on the T sections, the joints engaged and silicone run into the groove. Polyurethane foam is injected into the ceiling-to-wall joint to prevent condensation and ensure an airtight seal.
On a 500 m² cold store project in Tây Ninh (formerly Long An), the Tân Long team used 304 stainless rod hangers in place of galvanised steel. The damp environment inside a cold store rusts galvanised steel after 2–3 years in service — stainless hangers hold up for 10 years and more.
Step 5: cut the panels and fit doors and vents
Panels are cut to the door and vent openings with a low-speed disc cutter. Do not use a thermal cutter: the heat burns the EPS/PU core and destroys the insulating structure. An aluminium or stainless door frame is fitted into the opening and sealed with silicone all round for an airtight joint. Lights and vents are fitted the same way.
Step 6: seal the joints with silicone and fit the finishing corner trims
Heat-resistant silicone (rated −40°C to 120°C / −40°F to 248°F) is run into every panel joint to ensure a tight seal. Aluminium corner trims (1.1 mm thick) are fitted at every corner: wall-to-wall, wall-to-ceiling and wall-to-floor. For deep joints, or the ceiling-to-wall joint, the team fills with polyurethane foam before fitting the trim. This step determines the airtightness of the whole wall system — broken silicone runs or gaps behind corner trims cause condensation and heat loss.
Step 7: clean, inspect and hand over
Once complete, the team cleans all the panel surfaces and carries out the handover inspection. The criteria to be met: wall plumb ≤2 mm/2 m (0.08 inches/6.5 feet), joint gaps ≤1 mm, an even, unbroken silicone run, and corner trims tight with no gaps. The handover documentation includes as-built drawings and panel cleaning instructions (no chemicals that corrode the steel facing, and no high-pressure washer directed into the joints).
Technical standards to achieve when installing insulated panels
Once installed, the panel wall and ceiling system must meet standards for flatness, joint gaps, airtightness and insulating performance. These parameters directly affect the service life and energy efficiency of the building.
| Criteria | Standard value | Unit | Note |
| Wall plumb | ≤2 | mm/2m | Equivalent to ≤0.08 in/6.5 ft |
| Panel joint gap | ≤1 | mm | Check with a feeler gauge |
| Silicon | Even, unbroken | — | No breaks, no blisters |
| Corner trim | ≤0.5 | mm gap | Tight at every corner |
| Ceiling deflection | ≤5 | mm/4m | Check with a spirit level |
| Cold stores (additional) | ≤2°C variation | °C | Between zones inside the store |
For a cold store, the standards are stricter than for an ordinary partition. Door gaskets must seal 100%, anti-condensation measures at the ceiling-to-wall joint are mandatory, and the temperature variation between zones inside the store must not exceed 2°C. Meeting the standard is only the start. Many installation faults only show up after 1–3 months in service — spotting them early prevents damage.
Common panel installation faults and how to correct them
Panel installation faults usually occur at 3 stages: fixing the framing, engaging the joints and sealing. Spotting them early cuts repair costs and protects long-term insulating performance.
| Fault | Cause | How to avoid them |
| Panels out of true (not plumb) | U framing not level | Check with a laser before driving the fixing screws |
| Joint gap >1 mm | Joint profile dented in transit or by impact | Inspect the joint profile before fitting; reject damaged panels |
| Dented facing / burnt core when cutting | Thermal or high-speed cutter used | Low-speed disc cutter; use pre-cut panels where possible |
| Ceiling sagging | Rod hangers more than 1,200 mm apart | Keep hanger centres at ≤1,200 mm (47 in) |
| Panels sweating (condensation) | Broken silicone, joints open to moisture | Continuous silicone bead, tight corner trims, foam filler |
| Screws driven off line / through the core | No pilot drill, wrong torque setting | Use a pilot drill to locate, and set the torque correctly |
On a food factory project in Bình Dương, the Tan Long team found 12 panels with joint profiles dented by incorrect handling in transit. Fitted as they were, the resulting 2–3 mm gaps would have caused 15–20% heat loss at those points. The team rejected them and replaced them with new panels before continuing.
Many faults stem from choosing an inexperienced contractor, or from a failure to control the quality of incoming materials.
How to choose a reputable insulated panel contractor
Choosing a panel installation contractor means assessing 6 criteria: industry experience (at least 10 years on projects of comparable scale), reference projects (≥30 projects with photographs and case studies), material capability (an in-house factory or a panel supplier meeting the standard), a dedicated installation team (fitters experienced with panels, not general builders), warranty (12–24 months on the wall system), and a clear handover inspection procedure.
Tân Long, for instance, meets these criteria with more than 20 years in industrial refrigeration systems, a factory in Tây Ninh, and more than 100 completed projects for partners including Lotte, C.P. and Kyokuyo. Investors can review Tân Long's featured projects at https://tanlongvn.com/cong-trinh/ or call the hotline on 02838494943 for advice.
Frequently asked questions about insulated panel installation
How long does an insulated panel installation take?
It depends on the area and the size of the team. Walls and ceiling of 500 m² (5,382 sq ft): 5–7 days with 4–6 fitters. A simple 100 m² (1,076 sq ft) partition: 2–3 days. Dry construction is unaffected by weather and saves 20–30% on the cost of a brick wall.
EPS or PU panels: which suits a cold store?
PU panels insulate 35–40% better than EPS at the same thickness. Cold stores and blast freezers should use PU. EPS suits office partitions and ordinary factories where the budget is limited.
Can you install panels yourself without a contractor?
Installing a small panel wall of under 50 m² (538 sq ft) yourself is feasible if you have the experience and the right tools. Anything larger needs a professional contractor to guarantee the seal, the structural strength and safety.
How thick should an insulated panel be?
Thickness depends on the application. Ordinary partitions: 50–75 mm (2–3 inches). Chill rooms (0°C–10°C): 75–100 mm. Freezer stores (−18°C to −25°C): 100–150 mm (4–6 inches). Blast freezers (−35°C to −45°C): 150–200 mm (6–8 inches).
Take control of panel installation quality right from the preparation stage
The quality of a panel wall and ceiling system comes down to 3 main factors. The 7-step process must be followed in order — the sequence of work determines the airtightness of the whole system. The right accessories and the right panel specification account for 60–70% of long-term insulating performance. An experienced contractor reduces the risk of installation faults and early failure.
Investors should understand how panels are installed, whether to supervise the quality themselves or to choose the right contractor. Contact Tân Long at tanlongvn.com/lien-he/ for advice on the panel installation process best suited to your particular project.
See also:
- How to build a cold store: design and installation to industrial standards
- How to use cold storage temperature controller in simple detail
- What is a refrigeration system? Current types of industrial refrigeration systems
Related pages
- Cold store classification: 5 technical criteria and how to choose the right type
- Storing dried squid in bulk in a cold store: temperature and humidity standards
- Cold store repair: how to identify faults and the expert troubleshooting process
- How to store beef jerky in bulk: temperature standards and industrial cold storage systems
- Tan Long industrial cold storage
Engineer Nguyen Toan Thinh (Technical Director)
With over 18 years of practical experience in directing, consulting, designing, and constructing heavy industrial refrigeration systems, ASRS automated warehouses, and IQF freezing systems across more than 29 major national projects.
