Atlas Reroofing: When Old Self-Adhering Underlayment Can Remain
Bulletin dated: 2021 revision
Atlas prefers removing old self-adhering underlayment so the deck can be inspected and buildup avoided. Its cited exception allows covering one firmly bonded layer when removal would damage the deck, with specified lap offsets and extension beyond the old material
Atlas technical bulletin: Self Adhered Underlayment Removal and Replacement.
What this means for your roof
Atlas prefers removing old self-adhering underlayment so the deck can be inspected and buildup avoided. Its cited exception allows covering one firmly bonded layer when removal would damage the deck, with specified lap offsets and extension beyond the old material. Two or more existing layers should be removed. Local requirements still apply.
A useful question for your contractor
How many layers are present, and can the deck be inspected without concealing damage?
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: 2021 revision. The date shown identifies the manufacturer document used for this summary.
Read Atlas: Self Adhered Underlayment Removal and Replacement
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.