Undertile membrane, or underlay, is thick, waterproof plastic that is placed under the exterior roof. The roofing underlay essentially works as a secondary roof.
We install underlay to:
- prevent dust accumulation, especially from wind
- reduce attic pressure (suction on the tiles caused by strong winds)
The regulations specify that it is mandatory to install underlay on:
- cement tile roofs with pitches between 17.5 and 26 degrees
- cement tile roofs with pitches greater than 45 degrees
- cement tile roofs with all tile pitches in coastal areas (within 30 km of the sea)
This is usually a critical upgrade when assessing most roof repairs.
