3. Double-skin roofs and lighting parts

Metal roofs made of pre-painted or unpainted galvanized steel ribbed sheets may require materials that can be used to produce :

• or particular types of roofing, such as "double skin" roofs with parallel wefts, the provisions of which are defined in DTU 40.35 (NF P34-205-1, May 1997 – Travaux de bâtiment – Couvertures en plaque nervurées issus de tôles d'acier revêtues – Partie 1 : Cahier des clauses techniques);

• or lighting parts using translucent plates inserted in the running parts (GRP plates).

These provisions require the use and installation of materials or accessories defined below.