Products / DELTA-TRELA

DELTA-TRELA is a vapor-permeable roof underlayment for ventilated and non- ventilated roofs and facades clad in metal, made of a three-ply spunbonded polypropylene breather membrane thermally bonded to an 8 mm (about 5/16 inch) randomly oriented polypropylene fiber mat that ventilates the underside of the panels and drains moisture to the exterior in one installation step. It is laid parallel to the eaves with the mat facing up, needs DELTA-SEALING NAILS where fasteners go through it, and Dörken says it cuts rain and hail noise by up to 15 dB. The technical data sheet (dated 04/23/2026) prints a water vapor permeance of 69 perms (ASTM E96 procedure A) and 120 perms (procedure B), a fire class of E to EN 13501-1, a -40 to 176 degree F range, 1 m by 30 m rolls of about 25 lb, and a maximum UV exposure of 6 weeks.