The present invention provides a double-sidedly bondable planar element which has an electrical contacting layer via which it is self-regulatingly intrinsically heatable and at the same time has a high flexibility. The particular features of this planar element are that the planar element in the storage condition is adhesive on one side only, and is therefore particularly easy to handle, and that, on bonding, the adhesive passes through cutouts in the contacting layer, and the planar element thus becomes double-sidedly bondable. The invention further provides a method for the bonding of this planar element, including as a key step the passage of the adhesive through the cutouts in the contacting layer, thus turning a single-sidedly adhesive planar element into a double-sidedly adhesive planar element.