Depending on how it was constructed, homes with sloped, cathedral or vaulted ceilings can have little, or no, attic spaces in places. This occurs as the interior ceiling is often parallel (or nearly parallel) with the roof plane. Until recently, most older storey-and-a-half homes (built in the 1700’s to the 1960’s) commonly had poorer insulation / ventilation between the ceiling and the roof. Largely, this occurs as the space for insulation and ventilation is governed solely by the rafter dimension in these older homes. As a result, they had less of an “air wash” present compared to homes with traditional attic spaces. As a result, the life span of the shingles, rafters and roof sheathing can be reduced, heightening concerns with moisture & mould / fungus too.
With a greater opportunity for heat loss, there was a greater chance of ice damming also. Often additional insulation and or ventilation when accompanied with proper vapour barriers can improve these issues, but is often not possible, turning homeowners to look at spray foam as a retrofit. Newer homes built with scissor trusses to create these ceilings improved on these issues, however venting at soffit areas and ghosting / soot staining concerns may occur.