Additional sealing level
below the windows -
on the outside

Sealing the window sill

Window sills that are installed on the outside of window and façade elements are often made from aluminium profiles, sometimes from natural stone or, in exceptional cases, from wood. It is important that the end pieces of aluminium window sills are impermeable to driving rain. If this is not the case, or if condensation is likely to occur underneath the window sill, a second waterproof layer must be created using a tub-shaped sealing film (e.g. TEROSON FO 3 SK1). The film is adhered to the substructure profile of the window element and is guided over the external insulation layer down to the façade plaster. This protects the insulation from moisture penetration.
Bonding the TEROSON FO 3 SK1 foil with sealant­paste on the front edge of the façade­plaster is recommended. This creates an additional windproof layer. The height of the tray formation should end below the upper edge of the window sill on the right and left side of the window sill. The side sealing between the window sill and the façade plaster must be carefully planned and executed using appropriate products (e.g. sprayable sealant) (056 I 057).


In the event of condensation, a second water-bearing level must be created.

Anwendungsbild zum Klebstoffauftrag, um die Fassade abzudichten.
056 | Lateral sealing of the film with paste
Anwendungsbild zum Klebstoffauftrag, um die Fassade abzudichten.
057 | Window element with built-in window sill

Second sealing level for ETICS with FO 3 SK1 and PT ecoMAX 600

Second sealing level for clinker brick façades with FO 3 SK1 and PT ecoMAX 600

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