A full-deck self-adhered membrane limits outward drying. Owens Corning warns that trapped moisture in an unvented assembly can cause condensation, wood damage and buckling that may be mistaken for leaks
Owens Corning technical bulletin: Self-Adhered Underlayment Technical Bulletin.
What this means for your roof
A full-deck self-adhered membrane limits outward drying. Owens Corning warns that trapped moisture in an unvented assembly can cause condensation, wood damage and buckling that may be mistaken for leaks. The bulletin emphasizes adequate ventilation as soon as the membrane is installed.
A useful question for your contractor
Ask how moisture will leave the roof assembly before approving full-deck membrane coverage.
Ask for the answer to be tied to the actual roof condition and the exact product being installed. Keep the agreed repair or installation detail with your estimate and project photos.
Bulletin dated: May 2020. The date shown identifies the manufacturer document used for this summary.
Read Owens Corning: Self-Adhered Underlayment Technical Bulletin
This homeowner summary explains the cited bulletin. The complete manufacturer document and current product instructions govern the installation details. A requirement for one manufacturer or product should not be transferred to another without checking.