European Technical Approval ETA-06/0157 - ETA-Danmark

Page 18 of 23 of European Technical Approval no. ETA-06/0157
Annex 4
Design and installation details
Design and installation
The suitability of this kit is valid only if the installation is carried out in accordance with the manufacturer’s
instructions.
The kit may be laid in conditions normal to roofing work and must not be laid in rain, snow or heavy fog, nor if the
temperature falls below 2°C, unless specific precautions have been taken.
Laying and overlaps
The roll, with a nominal width of 110 or 55 cm, is aligned and unrolled in contact of the substrate. The DERBIGUM
will always be placed with its glass fibre armature, of which the stripes are visible, upwards.
The roll is then mechanically fixed with the fasteners and washers under the longitudinal overlaps (cfr Figure 1). The
longitudinal overlaps between adjacent membranes are 130 mm ± 10 mm (min 120 mm), the end overlaps are 150 mm.
Figure 1 : longitudinal overlap with mechanical fastener
The crossing of the overlaps is done with a T-joint. The edge of the corner is cut at 45° (cfr Figure 2).
Figure 2 : T-joint
Overlaps must be then welded over their whole widths, the edges are then correctly pressed down. A small quantity of
bitumen must be exuded from the overlap joint.