Flat roof: Isola Dobbelt Lag (double layer)

Isola Dobbelt Lag (double layer)

Isola Dobbelt Lag is a double-layer roof covering consisting of SBS polymer bitumen, with the upper layer welded to the underlay. These systems consist of Isola Kraftunderlag (strong underlay) and Isola Sveiseoverlag (welded upper layer).


Isola Dobbelt Lag is laid mechanically by laying Isola Kraftunderlag using washers and screws/bolts, or ordinary felt staples if laid on a wooden roof. The upper layer is then welded to the underlay to form a membrane providing full cover. For further information please click on Laying Instructions.


Isola has been granted Technical Approval by the Norwegian Building Research Institute (No. 2042).


Isola Dobbelt Lag complies with fire classification TA in respect of all types of underlay in accordance with NS 3919. This fire classification has also been certified by NCS; licence no. 538.

Areas of application

Isola Dobbelt Lag is used primarily as a roofing cover on buildings where the burden imposed by long-term building work may necessitate the choice of a dual-layer cover. This roofing system can be laid on all normal types of underlay consisting of concrete, light concrete, wood or heat-insulating sheets, and it is suitable for both sloping and flat roofs.


Isola Dobbelt Lag has properties that have been tailored to cope with our climatic conditions. Isola Kraftunderlag (underlay) creates a strong, sealed roof during periods when building work is being carried out, while the upper layer provides permanent protection from the weather. Once it has been laid this roof acquires considerable elasticity and strength.

Colour range

Isola Dobbelt Lag (upper layer) are available in slate gray, black and brick red.
For other colours - contact Isola as.

Roof mouldings

Matching roof mouldings are available on demand.