The Problems

Protecting the underside of your metal roof or cladding will ensure a longer roof life. Metal roofs and cladding are not sealed to the roof deck or sheathing, which allows moisture to easily get underneath the metal.

If moisture is allowed to accumulate, two problems can arise. The first is premature damage to the roof substructure, requiring removal of the metal and repair. The second is condensation on the underside of the metal, which can lead to corrosion and require the metal to be replaced sooner than necessary. 

The Solution

DELTA®-TRELA is a vapor-permeable underlayment with structured separation and drainage - specifically designed for metal roofs and façades with metal cladding, preventing corrosion and moisture accumulation underneath panels and ensuring the longevity of your metal roof. 

Product Details
Product Benefits
  • 8mm high randomly oriented studded fiber mat
  • Fiber mat is thermally bonded to a vapor permeable, watertight membrane.
  • 8mm studded fiber mat ventilates the underside of the metal panels
  • Drainage course – the studded structure reliably channels residual moisture to the exterior
  • Vapor-permeable, watertight fabric ensures airtightness and allows moisture within the roof cavity to escape via diffusion
  • Rattling noise from rain or hail is reduced by up to 15dB
  • Installed parallel to the eaves, with the studded structure facing upwards, the next section of membrane is overlapped in shingled fashion, ensuring that water is shed to the exterior
  • Burled, studded texture provides a non-slip surface during installation
  • One-step installation – faster and easier than applying an underlayment and a separation layer in independent steps, saving time and money on project schedules
  • Included with every roll is a package of 120 DELTA®-SEALING NAILS used for fastening 

Additional Resources

Guide Specifications

Installation Guides

Product Details

Safety Data Sheets

Technical Data

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