Illustration Source: CHBA Manual, Fig.12.20, Pg.229 Photo Source: Summerhill

Photo Source: Summerhill

Sealing Attic Hatches:

The attic hatch can be sealed in the same way windows, doors, and skylights are sealed. Seal the polyethylene to the attic hatch frame and use low-expansion foam in the frame cavities, after the unit is installed.