| Indoor Climate Class | Description | Examples |
|---|---|---|
| I | Buildings with little or no moisture production | – Showroom – Storage room for dry goods |
| II | Buildings with limited moisture production per m³ and good ventilation | – Sports hall – Large house – Commercial premises |
| III | Buildings with higher moisture production per m³ and moderate to sufficient ventilation | – Buildings with RH < 60% – Small houses – Restaurants – Hospitals – Low-rise buildings with air conditioning |
| IV | Buildings with high humidity levels | – Buildings with RH > 60% – Swimming pools – Wet production and storage areas: laudries, breweries |
In practice, the choice is simpler.
- To best protect your insulation against internal condensation, it must be “wrapped” between two waterproof bitumen layers: the vapour control layer and the underlayer must be perfectly sealed and vapour-tight (see details below).
- A vapour control layer only functions properly when it can seal both longitudinal and transverse overlaps.
- In welded systems, the wind resistance of the entire roof structure is also determined by how well the vapour control layer adheres to the substrate. No risks should be taken here. With bonded or torch-applied systems, always ensure you choose a vapour control layer that adheres well to the surface.
Taking these important factors into account, it becomes easier to choose between:
- a) 3 mm reinforced bituminous membranes for climate classes I to III, or
- b) Vapour control layers with an aluminium foil facing, suitable for climate class IV.