# Layers

<figure><img src="https://content.gitbook.com/content/fKJnzF2TwHA3APPbiCpF/blobs/E0o2RXN9jl85Aqe8BKS6/image.png" alt=""><figcaption></figcaption></figure>

### Subdivide Layers

ISO 13788 recommends subdividing elements with a thermal resistance exceeding 0.25 m²·K/W into multiple notional layers, each with a maximum thermal resistance of 0.25 m²·K/W. These subdivisions should be treated as individual material layers, with interfaces between them considered in all calculations.