Vent flashing is flashing specifically designed to seal around a roof vent penetration, which can take various shapes and sizes depending on the specific vent type, from round plumbing vent boots to rectangular flashing for bathroom exhaust fans or kitchen range hood vents.
Because vent shapes and sizes vary considerably across different applications, vent flashing products come in a range of configurations, each engineered to match a specific vent type’s dimensions and installation requirements.
Proper integration between the vent flashing and the surrounding roofing material, with adequate overlap and sealed connections, is essential regardless of the specific vent shape involved.
What Types of Vent Flashing Are There?
- Round rubber boot flashing for plumbing vents
- Rectangular flashing for exhaust fan or range hood vents
- Specialized flashing for larger mechanical roof vents
- Custom-fabricated flashing for unusual vent configurations
Why Is Vent Flashing Important?
Each type of roof vent creates its own specific penetration shape and size, and using flashing properly matched to that particular vent, rather than improvising with a mismatched or generic product, is essential to achieving a genuinely watertight seal at the penetration. Mismatched or improperly sized vent flashing is a common installation shortcut that can lead to leaks even when the flashing material itself is otherwise adequate quality.
Sealant used at vent flashing connections, particularly around the base where it meets the vent itself, requires periodic inspection and resealing as part of routine roof maintenance, since this sealant tends to degrade from sun exposure well before the surrounding roofing material shows comparable wear.
Vent Flashing vs. Pipe Flashing
Vent flashing is the broader category covering flashing for any vent type penetrating the roof. Pipe flashing specifically refers to the round rubber boot style most commonly used for plumbing vent pipes, one particular subset within the broader vent flashing category.