Roofing Terms Explained

Understanding roofing terminology is crucial for homeowners, contractors, and anyone involved in building or maintaining roofs.

This comprehensive guide explains the most common roofing terms, providing you with a solid foundation of knowledge to help you make informed decisions about roofing projects.

A

• A-Frame Roof: A roof with steeply angled sides that form an "A" shape, typically used in simple structures like cottages and cabins.

• Asphalt Shingles: Common roofing material in USA made from asphalt-saturated base covered with mineral granules, known for affordability and ease of installation.

B

• Balcony Roof: A roof or covering over a balcony, often an extension of the main roof.

• Battens: Thin strips of wood or metal attached to the roof deck to provide a base for roofing materials such as tiles or slates.

• Bitumen: A sticky, black, viscous material used for waterproofing roofs, often found in asphalt shingles and roofing felt.

C

• Canopy: A roof-like structure providing shelter over a door, window, or porch, often decorative.

• Cap Flashing: Flashing used at the top of a vertical structure or parapet wall to prevent water ingress.

• Capping: Protective covering or finishing piece on the ridge or hip of a roof.

• Chimney Flashing: Waterproofing material installed around the base of a chimney to prevent leaks.

• Clay Tiles: Durable, fire-resistant roofing material made from molded clay, commonly used in Mediterranean and Spanish-style architecture.

• Collar Beam: Horizontal beam connecting two rafters at a point partway up the roof, adding strength and rigidity.

D

• Decking: The structural base for the roof, usually made of plywood or OSB (Oriented Strand Board), to which roofing materials are attached.

• Dormer: A vertical window that projects from a sloping roof, often adding light and space to an attic or loft.

• Drip Edge: A metal flashing installed at the roof's edge to guide water away from the fascia and into the gutter.

• Dry Ridge System: A method of fixing ridge tiles without mortar, using screws and clamps for a secure and weatherproof fit.

E

• Eaves: The lower edge of a roof that overhangs the building’s exterior walls, providing protection from water runoff.

• EPDM: Ethylene Propylene Diene Monomer, a durable synthetic rubber roofing membrane used in flat roofing applications.

• Exposure: The portion of a roofing material left exposed to the weather, such as the visible part of a shingle or tile.

F

• Fascia: The vertical finishing edge connected to the ends of the rafters, supporting the bottom row of tiles and the guttering.

• Felt: A layer of material placed under shingles or tiles to provide a secondary barrier against water.

• Flashing: Thin sheets of lead or other metal installed at joints and roof penetrations to prevent water ingress.

• Flat Roof: A roof with a near-level surface, typically with a slight pitch for drainage.

• Fibre Glass Roof: Also known as GRP roofing, can potentially last for more than thirty years.

G

• Gable: The triangular upper part of a wall at the end of a ridged roof.

• Gable Roof: A roof with two sloping sides that come together at a ridge, creating a gable at each end.

• GRP: Also know as Fibre Glass is a type of material used typically in flat roofing.

• Gutter: A channel along the eaves designed to collect and direct rainwater away from the building.

H

• Hip: The external angle formed by the intersection of two sloping roof planes.

• Hip Roof: A roof with slopes on all four sides, which meet at the corners to form hips.

I

• Ice Dam: A build-up of ice along the eaves of a roof, which can prevent melting snow from draining properly, leading to leaks.

• Interlocking Tiles: Roofing tiles designed to fit together, providing a secure and weatherproof seal without the need for mortar.

J

• Joists: Horizontal structural members used to support a ceiling or floor.

K

• Kickout Flashing: A special type of flashing that directs water away from the wall and into the gutter, often used where the roof meets a vertical wall.

L

• Lead Flashing: A traditional and durable flashing material made from lead, used to seal joints and roof penetrations.

• Lean-to Roof: A roof with a single slope, typically used for extensions or porches.

• Lightwell: A space or shaft in a roof that allows natural light to penetrate the interior of a building.

M

• Mansard Roof: A four-sided roof with two slopes on each side, the lower slope being steeper than the upper slope.

• Membrane Roofing: Roofing systems using sheets of material, such as EPDM or TPO, to create a continuous waterproof barrier.

O

• Overhang: The part of the roof that extends beyond the exterior walls, providing protection from rain and snow.

P

• Parapet: A low wall along the edge of a roof, balcony, or terrace.

• Pitch: The steepness or angle of a roof, typically expressed as a ratio of vertical rise to horizontal run.

• Purlin: A horizontal beam running along the length of the roof, supporting the rafters.

Q

• Quoin: The external angle of a building or the bricks used to form that angle, often used decoratively.

R

• Rafter: A sloping beam that supports the roof deck and roofing materials.

• Rake: The inclined edge of a sloped roof over a wall.

• Ridge: The highest point on a roof, where two sloping sides meet.

• Ridge Tiles: Specially designed tiles used to cover and protect the ridge of a roof.

• Roll Roofing: A type of roofing material that comes in large rolls, used primarily for low-slope roofs.

S

• Sarking: A layer of material placed over the rafters and under the roofing material to provide insulation and waterproofing.

• Shed Roof: A single-sloped roof, often used for additions or lean-to structures.

• Shingles: Flat or curved tiles made from various materials (asphalt, wood, slate) used as roof covering mainly in USA.

• Soffit: The underside of the eaves or roof overhang, often ventilated to provide airflow.

• Step Flashing: Flashing pieces installed in layers to prevent water from entering at roof joints and penetrations.

• Structural Decking: The base layer of the roof, providing structural support for the roofing materials.

T

• Terracotta Tiles: Roofing tiles made from fired clay, known for their reddish-brown color and durability.

• Truss: A framework of beams supporting the roof, providing structural strength.

• TPO: Thermoplastic Polyolefin, a single-ply roofing membrane known for its durability and energy efficiency.

U

• Underlayment: A protective layer placed between the roof deck and the roofing material to provide additional waterproofing.

• Under Cloaking: A protective layer placed underneath the first row of roof tiles/slates

V

• Valley: The internal angle formed by the intersection of two sloping roof planes, directing water to the eaves.

• Velux Window: Also referred to as a skylight, is a window that is commonly found on the roof.

• Vent Pipe: A pipe that allows air to enter or exit the roof space, often used for plumbing or ventilation systems.

• Venting: The process of allowing air to circulate within the roof space to prevent moisture build-up and condensation.

W

• Waterproof Membrane: A layer of material used to prevent water penetration, often used in flat roofing systems.

• Weatherproofing: The process of making a roof resistant to weather elements such as rain, wind, and snow.

• Wind Uplift: The upward force exerted by wind on a roof, which can cause damage if not properly addressed.

X

• X-Bracing: A method of bracing roof structures using crossed beams to provide additional stability and strength.

Y

• Yankee Gutter: A gutter system integrated into the roof plane, commonly used in historic buildings.

Z

• Zinc Roofing: A durable and long-lasting roofing material made from zinc, often used for its aesthetic appeal and low maintenance.