Thermal insulation calculator
for sandwich panels
Find out exactly which sandwich panel thickness your project needs to comply with current regulations. Results based on EN14509 certified data.
Calculate the sandwich panel thickness you need
Select your panel, project type and conditions. Results are instant.
U = 1 / (Rsi + e/λ + Rse)Rsi=0.13 · Rse=0.04 m²K/W · λ=0.021 W/mKThe results of this calculator are indicative and non-binding. U-value and R-value data comes from EN14509 certified technical datasheets.
Before applying this data on a real project, it is essential to consult a qualified engineer or architect.
Our technical team will advise you with no obligation.
What sandwich panel thickness do I need by application?
Sandwich panel thickness depends on the building's use, climate zone and thermal insulation requirements. An industrial warehouse is not the same as a cold room or a house. The values below are approximate and indicative: get the exact thickness for your project using the calculator above, which uses EN14509 certified U-values.
🏭 Industrial buildings and warehouses
The key factor in industrial buildings is the temperature difference between inside and outside and whether there will be HVAC or not. The greater the thermal differential and the more precise the temperature control required, the more insulation you will need to maintain energy efficiency and avoid condensation. See the Master-C roofing panel and Master-F facade panel datasheets for all available thicknesses.
| Situation | Roof (approx.) | Facade (approx.) |
|---|---|---|
| No HVAC / basic protection | ≈ 40 mm | ≈ 40 mm |
| Basic or partial heating | ≈ 60 mm | ≈ 50 mm |
| Full air conditioning | ≈ 80 mm | ≈ 80 mm |
| Industrial process / controlled temperature | ≈ 100 mm | ≈ 80–100 mm |
* Approximate values. Use the calculator with your actual project temperatures to get the exact thickness and certified U-value.
🏠 Residential buildings — Spanish CTE DB-HE1 standard
In residential and non-residential buildings in Spain, the CTE DB-HE1 (Royal Decree 450/2022) sets maximum U-values by climate zone. As a guide, southern and eastern coastal areas require less insulation, while the inland peninsula, north and mountain areas need greater thickness for both roof and facade. The calculator automatically assigns the climate zone when you select the province. For modular construction see the Master-Modul modular panel.
| CTE Zone | Roof (approx.) | Facade (approx.) | U max. reference |
|---|---|---|---|
| Zone α / A — Canary Islands, Andalusia | ≈ 40–50 mm | ≈ 40 mm | 0.73 / 0.62 W/m²K |
| Zone B — Levante, Balearic Islands | ≈ 50–60 mm | ≈ 50 mm | 0.52 / 0.44 W/m²K |
| Zone C — Madrid, Barcelona, Toledo | ≈ 60–80 mm | ≈ 60 mm | 0.41 / 0.35 W/m²K |
| Zone D — Castile, Navarre, La Rioja | ≈ 80 mm | ≈ 80 mm | 0.38 / 0.32 W/m²K |
| Zone E — Ávila, Soria, mountain areas | ≈ 80–100 mm | ≈ 80 mm | 0.35 / 0.29 W/m²K |
* Approximate values based on available catalogue thicknesses. Actual thickness depends on the chosen panel and its EN14509 certified characteristics.
❄️ Cold rooms and refrigerated spaces
Cold rooms are not governed by the CTE but by the temperature gradient between inside and outside: the greater the thermal differential, the greater the thickness required. The Master-Frigo cold room panel is specifically certified for this use with high-density foam and hermetic joints that prevent thermal bridges. Always confirm the final thickness with our technical team.
| Room type | Approx. interior temp. | Wall (approx.) | Ceiling (approx.) |
|---|---|---|---|
| Positive chilled storage | 0°C to +8°C | ≈ 60 mm | ≈ 60 mm |
| Negative chilled storage | −4°C to −10°C | ≈ 80 mm | ≈ 100 mm |
| Freezing | −10°C to −25°C | ≈ 100–120 mm | ≈ 100–120 mm |
| Deep freeze / blast | −26°C to −46°C | ≈ 150 mm | ≈ 150 mm |
* Approximate values from Master-Frigo technical datasheet. Always consult a specialist engineer to confirm the final thickness for your project.
Not sure which panel best suits your project? Browse the full Masterpanel panel catalogue or use the calculator above to get the exact thickness with a certified U-value.
What is U-value (thermal transmittance) and why does it determine panel thickness?
The U-value (thermal transmittance) measures how much heat passes through a sandwich panel per square metre for each degree of temperature difference between inside and outside, expressed in W/m²K. The lower the U-value, the better the panel's thermal insulation.
La Spanish standard CTE DB-HE1 sets maximum U-values by climate zone and building element. El cálculo sigue la norma EN ISO 6946 con datos certificados EN14509:
U = 1 / (Rsi + e/λ + Rse)
- Rsi = 0.13 m²K/W — interior surface resistance
- Rse = 0.04 m²K/W — exterior surface resistance
- e — core thickness in metres
- λ = 0.021 W/mK — thermal conductivity of Masterpanel PUR polyurethane
Using this formula, an 80 mm panel achieves U = 0.26 W/m²K, sufficient to comply with the CTE standard in all Spanish climate zones for roof elements.
CTE climate zones in Spain: maximum U-values by province
The CTE DB-HE1 (Royal Decree 450/2022) classifies Spain into 6 climate zones. The calculator automatically assigns the zone when you select the province.
Source: CTE DB-HE1 (Royal Decree 450/2022). Maximum admissible U-values for roofs and facades in new construction. Check your municipality's climate zone →
What U-value does the CTE require for roofs and facades?
The Spanish Technical Building Code (CTE) — Basic Document HE1, as revised by Royal Decree 450/2022, sets the maximum U-values for building envelope elements in new construction and major renovations.
| CTE Zone | Roof U max. | Facade U max. | Representative provinces |
|---|---|---|---|
| α | 0,94 W/m²K | 0,80 W/m²K | Canary Islands, south coast |
| A | 0,73 W/m²K | 0,62 W/m²K | Almería, Cádiz, Málaga, Sevilla |
| B | 0,52 W/m²K | 0,44 W/m²K | Alicante, Murcia, Valencia, Balearic Islands |
| C | 0,41 W/m²K | 0,35 W/m²K | Barcelona, Madrid, Toledo, Badajoz |
| D | 0,38 W/m²K | 0,32 W/m²K | Burgos, Salamanca, Valladolid, Navarre |
| E | 0,35 W/m²K | 0,29 W/m²K | Ávila, Segovia, Soria, mountain areas |
How to find the climate zone for your municipality? The CTE climate zone finder lets you check the zone assigned to any municipality in Spain.
📌 Note: Table values correspond to the current CTE DB-HE1 (Royal Decree 450/2022). Always check the official consolidated text at codigotecnico.org before drafting any technical project.
