Measures · External insulation
External thermal insulation (ETICS) thickness FREE
Work out the thickness of external thermal insulation (ETICS) for the climate zone. Below the result you find the formula and the standard.
Indicative pre-sizing. It does not replace a structural calculation signed by a licensed engineer. For seismic zones with agS (design ground acceleration) > 0.15g, long spans or use classes III/IV → talk to a structural engineer.
Pick a calculation from the list to start.
Formula, example and standard
s = λ · (1/U_target − 1/U_current)
Example with the starting values (Climate zone: E · 1400-3000 HDD; Material λ: 0.035 W/mK; Current wall U: 1.2 W/m²K): Insulation thickness: 10.5 cm. U_target zone E = 0.26 W/m²K.
- U_target from DM Requisiti Minimi 26/06/2015 (the Italian minimum energy requirements decree), Appendix B (in force since 2021).
- Typical λ: white EPS 0.035 · graphite EPS 0.031 · rock wool 0.036 · wood fiber 0.040.
- Always check interstitial condensation (Glaser method) and thermal bridges.
Source: DM Requisiti Minimi 26/06/2015 · DPR 412/93 · biblus.acca.it
Indicative pre-sizing: it does not replace a calculation signed by a licensed engineer.
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