One of the most critical decisions in industrial facility, factory or warehouse construction is choosing the right roof sandwich panel type. The wrong panel selection can mean high energy costs, fire risk, early maintenance costs and structural performance losses. While sandwich panel use in the Turkish construction industry grows by approximately 8-10% annually, determining the right filling material has become an increasingly critical engineering decision. In this guide, we compare polyurethane (PU), mineral wool (rock wool) and EPS (expanded polystyrene) filled roof sandwich panels within the framework of technical data, standards and application scenarios.
What is a Sandwich Panel and Why is it Preferred for Roofs?
A sandwich panel is a composite building element produced with insulation filling placed between two metal surfaces (usually galvanized steel or aluminum). Defined under the TS EN 14509 standard, these panels are widely preferred in industrial structures because they combine the functions of load-bearing, insulation and cladding in a single element.
The main reasons why sandwich panel use is preferred in roof applications:
Bosan Industrial Building offers engineering-supported technical drawings and application planning at every stage from site survey to installation completion with its turnkey project model.
Polyurethane (PU) Filled Roof Sandwich Panel
Polyurethane sandwich panel is the most widely used panel type in industrial roof applications today. Rigid polyurethane foam filling produced according to the TS EN 13165 standard stands out with its extremely low thermal conductivity coefficient (λ = 0.022 – 0.024 W/mK).
Technical Specifications
| Property | Value |
|—|—|
| Thermal conductivity coefficient (λ) | 0.022 – 0.024 W/mK |
| U value at 100 mm | ≈ 0.21 W/m²K |
| Fire class (filling) | B – C class (EN 13501-1) |
| Density | 38 – 42 kg/m³ |
| Available thicknesses | 40, 50, 60, 80, 100, 120, 150, 200 mm |
The strongest aspect of the PU panel is its thermal performance: Approximately 1.5 times more thickness is required to achieve the same U value with mineral wool. This situation directly affects purlin heights and structural load in roof construction.
Standout applications: Logistics warehouses, cold storage roofs, food production facilities, automotive assembly factories and all kinds of industrial structures where energy efficiency is at the forefront.
Point to note: In terms of fire safety, PU filling is in class B or C. Within the scope of the Regulation on Protection of Buildings from Fire (BYKHY), it may be mandatory to prefer mineral wool for facilities in the high-risk class.
Mineral Wool (Rock Wool) Filled Sandwich Panel
Mineral wool filled panels are the preferred solution in structures where fire safety is the primary criterion. Produced according to the TS EN 13162 standard, the rock wool filling offers A1 fire class (non-combustible) performance; this makes it indispensable for high-risk class facilities within the scope of BYKHY.
Technical Specifications
| Property | Value |
|—|—|
| Thermal conductivity coefficient (λ) | 0.033 – 0.040 W/mK |
| U value at 100 mm | ≈ 0.35 – 0.38 W/m²K |
| Fire class (filling) | A1 – A2 (non-combustible) |
| Density | 100 – 120 kg/m³ |
| Sound absorption coefficient | αw ≈ 0.75 – 0.90 |
The most critical advantage of the mineral wool panel is its fire resistance. Rock wool filling, which can maintain its structural integrity even above 1000°C, can become a mandatory choice especially in chemistry, petrochemistry, pharmaceutical production and defense industry facilities.
Sound insulation performance is another feature that highlights the mineral wool panel. Compared to PU and EPS, it offers a much higher acoustic absorption coefficient.
Standout applications: Chemical and petrochemical facilities, pharmaceutical production buildings, airport hangars, shopping mall roofs and facilities requiring special precautions within the scope of BYKHY.
EPS (Expanded Polystyrene) Filled Sandwich Panel
EPS sandwich panel offers an economical alternative for projects seeking low initial investment cost. Its thermal insulation performance is positioned between PU and mineral wool; the λ value is in the 0.035 – 0.038 W/mK range.
Technical Specifications
| Property | Value |
|—|—|
| Thermal conductivity coefficient (λ) | 0.035 – 0.038 W/mK |
| U value at 100 mm | ≈ 0.33 – 0.36 W/m²K |
| Fire class (filling) | E – F (flammable) |
| Density | 12 – 20 kg/m³ |
| Cost comparison | 15-25% lower than PU |
The most obvious disadvantage of EPS is its fire performance. The filling material is in class E or F; therefore, its use is limited in facilities that carry fire risk or are restricted within the scope of regulations. However, it may be a reasonable choice for short-lived temporary structures, agricultural warehouses or budget-constrained projects.
EPS sandwich panel price is generally the most competitive level in the market; however, when the life cycle cost (energy costs + early renewal) is calculated, its long-term advantage may decrease compared to PU or mineral wool panel.
Which Roof Sandwich Panel is Right for You?
Correct panel selection depends not on a single criterion, but on the evaluation of multiple factors together:
| Criterion | PU Panel | Mineral Wool | EPS Panel |
|—|—|—|—|
| Thermal performance | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐ |
| Fire safety | ⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐ |
| Sound insulation | ⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐ |
| Initial investment cost | ⭐⭐⭐ | ⭐⭐ | ⭐⭐⭐⭐⭐ |
| Long-term energy savings | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐ |
Within the scope of TS 825 Thermal Insulation Rules in Buildings, minimum U value requirements have been determined according to the climate zones of Turkey. In the 3rd and 4th climate zones (Central Anatolia, Eastern Anatolia), the U ≤ 0.25 W/m²K value required for the roof may not be met with standard thickness EPS panel; in these cases, PU or thicker mineral wool panel becomes mandatory.
Bosan Industrial Building’s expert team offers the most suitable panel type, thickness and profile selection for your facility within the scope of free technical consultancy after site survey and project analysis. You can visit bosanyapi.com.tr for detailed project information.
Points to Consider in Roof Sandwich Panel Installation
As important as correct panel selection, correct installation also directly determines the performance of the structure. The vast majority of installation errors lead to thermal bridge formation, condensation problems and sealing losses at panel-to-panel transition points.
Basic installation criteria include proper purlin spacing, screw application according to manufacturer specifications, sealing tape application at panel joints, and proper roof slope (minimum 5% recommended).
Bosan Industrial Building applies engineering-supported project planning as a standard process before installation in projects carried out throughout Turkey, especially in Kocaeli, Istanbul and Ankara.
FAQ: Frequently Asked Questions About Roof Sandwich Panel
Which is better, polyurethane or mineral wool sandwich panel?
Both panel types have different use cases where they stand out. Polyurethane (PU) filled panel offers better thermal performance in facilities where energy efficiency is at the forefront thanks to its low lambda value (λ = 0.022 – 0.024 W/mK). Mineral wool filled panel is preferred in structures where fire safety is critical with its A1 fire class. The choice should be made according to the facility’s intended use, fire risk class, regional climate conditions and budget parameters.
How much does EPS sandwich panel cost and when should it be preferred?
EPS sandwich panel offers approximately 15-25% lower initial investment cost compared to PU panel. However, due to its low energy efficiency and limited fire performance, its long-term cost may be higher.
Get expert consultation for your project: bosanyapi.com.tr | +90 530 282 04 49 | [email protected]
Share: