Roofing Terminology Dictionary (A–Z)
Roofing terminology is often confusing for homeowners because many terms are technical, trade-specific, or used inconsistently. This dictionary explains common roofing terms in plain language, focusing on how they relate to roofing systems rather than marketing claims.
A
The controlled movement of air through the attic or roof cavity to manage heat and moisture levels within the roofing system.
A layer within a building assembly designed to limit uncontrolled air movement, reducing heat loss and moisture transport.
B
Raised bubbles on roofing materials caused by trapped moisture, gas expansion, or improper installation conditions.
A low-slope roofing system composed of multiple layers of bitumen and reinforcing fabrics.
C
Moisture that forms when warm, humid air contacts a cold surface within a roof assembly.
A secondary flashing component installed over base flashing to prevent water intrusion at roof-to-wall intersections.
D
The structural surface to which roofing materials are attached, typically made of wood sheathing or concrete.
A metal edge installed at roof perimeters to direct water away from fascia and underlying components.
F
A mechanical attachment, such as a nail or screw, used to secure roofing components to the roof deck or structure.
Metal or membrane material used to seal transitions and prevent water entry at joints, penetrations, and changes in plane.
I
A ridge of ice that forms at roof edges when melting snow refreezes, trapping water and increasing leak risk.
Material used to reduce heat transfer through the roof assembly, affecting energy performance and snow melt patterns.
M
A layer designed to limit moisture movement within a roofing or building assembly.
R
A ventilation component installed along the roof ridge to allow warm air to exhaust from the attic space.
The complete combination of materials and components that make up a roofing system.
U
A protective layer installed beneath the primary roofing material to provide secondary moisture protection.
V
A layer intended to slow vapor diffusion through a roof or wall assembly.
W
The force created by wind pressure that can lift roofing materials if systems are not properly designed or fastened.
This dictionary will continue to expand as additional roofing terminology is added to the Knowledge Center.