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 📖 The JSIU Roofing Glossary: Australian Terminology & Standards

How to use this guide:This glossary covers over 100 essential roofing terms used in the Australian construction industry. It references key Australian Standards (AS) to help you understand the quality and compliance required for your home.

• Access Hatch: A specific opening (usually in commercial roofs or ceiling spaces) to allow safe entry for maintenance.
• Aluminium Flashing: A corrosion-resistant soft metal used for waterproofing joints, specifically compatible with Zinc/Alum roofs where lead cannot be used due to galvanic corrosion.
• Anti-Ponding Board: A board installed at the eaves line to prevent sarking from sagging and collecting water (ponding). Critical for low-pitch roofs.
• Apex: The highest point of a gable roof where the two sloping sides meet.
• Apron Flashing: A one-piece flashing, usually metal, used at the junction of a roof slope and a vertical wall or chimney.
• AS 1562: The Australian Standard for Design and Installation of Sheet Roof and Wall Cladding (Metal Roofing).
• AS 2049: The Australian Standard for Roof Tiles (Product quality).
• AS 2050: The Australian Standard for Installation of Roof Tiles (How they must be fixed).
• AS/NZS 3500: The Australian Standard for Plumbing and Drainage (Gutters and Downpipes).
• Back Tray: The portion of a flashing that extends up under the roof cladding to prevent water blow-back.
• Barge Board: The timber or metal board that runs along the sloping edge of a gable roof.
• Barge Capping: The folded metal or tiled cap that covers the barge board and the edge of the roof tiles to waterproof the gable end.
• Battens: Timber or metal strips fixed horizontally to rafters. Roof tiles or metal sheets are screwed/nailed into these.
• Bedding: A sand and cement mortar mixture used to secure ridge caps to the roof tiles. It provides the foundation for "Pointing."
• Bellcast: A slight flare or curve at the bottom of a roof slope/eave, often found in heritage federation homes.
• Biscuit: A slang term for a flat, thin clay roof tile (Shingle).
• Blanket Insulation: Flexible thermal insulation (usually glasswool) rolled out under metal roofing sheets.
• Blue Mountain Mesh: A popular brand of steel gutter guard mesh used in bushfire-prone areas.
• Box Gutter: A concealed internal gutter, usually rectangular, placed between two parallel roof slopes or behind a parapet wall.
• Bullnose: A curved style of verandah roof sheeting common in Victorian-era homes.
• Bushfire Attack Level (BAL): A rating (e.g., BAL-12.5, BAL-40) determining the fire resistance required for roofing materials in specific zones.

• Damp Proof Course (DPC): A barrier (usually polyethylene) built into masonry walls to prevent moisture rising; often integrates with roof flashings.
• Dead Load: The permanent weight of the roof structure itself (timber, tiles, insulation) that the frame must support.
• Decking: A term for metal roof sheeting profiles (e.g., "Klip-Lok Decking").
• De-glazing: The process where old terracotta tiles lose their shiny surface and become porous.
• Downpipe (DP): The vertical pipe that carries water from the gutter to the stormwater drain.
• Drip Groove: A small groove cut under the nose of a roof tile to stop water tracking backward via capillary action.
• Dropper: The chute or nozzle connecting the gutter to the downpipe (also called a "Pop").
• Dry Pan: The flat part of a roof tile profile (as opposed to the roll).
• Dutch Gable: A roof style combining a hip roof with a small gable at the top.
• Eaves: The lower edge of the roof that overhangs the walls.
• Eaves Comb Filler: A plastic comb strip nailed to the fascia to stop birds entering under the bottom row of tiles.
• Expansion Joint: A break in the structure or guttering designed to allow materials to expand and contract with heat without buckling.
• Fall: The slope or gradient of a gutter or roof to ensure water flows to the outlet. Minimum fall for gutters is usually 1:500.
• Fascia: The vertical board (timber or metal) under the roof edge which carries the gutter.
• Fascia Cover: A metal capping installed over timber fascia to eliminate the need for painting.
• Fasteners: The collective term for nails, screws, and clips used to secure roofing.
• Finial: A decorative ornament (spike or ball) placed at the apex of a roof (common on Federation homes).
• Flashing: Strips of impervious material (Lead, Zinc, Colorbond) used to waterproof junctions/angles in the roof.
• Flexible Pointing: A pre-mixed, rubberized compound applied over bedding cement to seal ridge caps. It moves with the roof to prevent cracking.
• Freeboard: The vertical distance between the water level in a gutter and the overflow point (safety margin).
• Fretting: The crumbling of mortar or brickwork due to salt attack or age.

• Gable: The triangular vertical section of wall at the end of a pitched roof.
• Galvanic Corrosion: A chemical reaction causing rust when incompatible metals touch (e.g., Lead flashing on a Zinc roof).
• Gauge: The distance between the varying batten courses; determines the overlap of the tiles.
• Gutter Guard: Mesh or perforated metal installed over gutters to prevent leaf blockage.
• Head Lap: The distance the top tile is overlapped by the tile above it (critical for waterproofing).
• Hip: The external angle formed where two roof faces meet (the opposite of a valley).
• Hip Starter: The first ridge cap at the bottom of a hip, often sealed or blocked off.
• Isolation Strip: A piece of plastic or bitumen felt used to separate incompatible metals to stop corrosion.
• Joist: Horizontal timber members that support the ceiling (distinct from rafters which support the roof).
• Klip-Lok: A type of metal roofing that snaps onto clips, requiring no screws to penetrate the sheet (excellent for low pitch).

• Lichen: A fungus/algae organism that grows on roof tiles; its roots can eat into the surface of concrete tiles.
• Live Load: Temporary weight on the roof (e.g., a person walking, snow, wind).
• Manhole: The access point to the ceiling cavity.
• Marseille Tile: A classic French-style terracotta tile with a double-roll profile, very common in Melbourne.
• Mitre: A generic term for a diagonal join (e.g., where two gutters meet at a corner).
• Monier: A major Australian brand of concrete and terracotta roof tiles.
• Mortar: The sand and cement mix used for bedding ridge caps.
• Nogging: Short timber pieces fixed between rafters or studs for bracing.
• Non-Combustible: Materials that will not burn (required in high BAL zones).
• Nose: The bottom edge of a roof tile.
• Over-flashing: A secondary flashing that covers the upstand of a primary flashing (usually cut into brickwork).
• Overflow: A safety outlet (spout or slot) in a gutter system to release water if the downpipe blocks, preventing backflow into the house.

• Parapet: A low protective wall extending above the roofline.
• Penetration: Any object passing through the roof surface (e.g., vent pipe, skylight, chimney).
• Pitch: The angle or steepness of the roof slope, measured in degrees. (Standard tile roof is 20°+).
• Pitched Roof: A roof with sloping surfaces (as opposed to a flat roof).
• Point-Up: The act of repairing or applying flexible pointing to ridge caps.
• Purlin: Horizontal structural members (steel or timber) spanning trusses to support roof sheeting.
• Quad Gutter: The traditional "D" profile gutter seen on most Australian homes.
• Rafter: The main sloping timber structural beam running from the ridge to the eaves.
• Rainhead: A box-shaped container at the top of a downpipe acting as a funnel/external sump for box gutters.
• Re-bedding: The process of removing old mortar and laying fresh cement for ridge caps.
• Ridge: The highest horizontal line where two roof slopes meet.
• Ridge Cap: The V-shaped or curved tiles covering the ridge line.
• Roof Safety Mesh: Wire mesh installed under commercial metal roofs to prevent falls during construction.

• Safety Anchor: A permanent metal loop fixed to the roof structure for hooking a safety harness.
• Sarking: A reflective foil laminate installed under tiles/metal. It provides thermal insulation, draft proofing, and acts as a secondary water barrier.
• Scupper: An opening in a parapet wall to allow water to drain from a box gutter.
• Sealant: Silicone or polyurethane mastic used to waterproof gaps.
• Shake: A wooden roof tile (cedar shake), rare in Australia but seen in imports.
• Sheet Metal: Refers to Colorbond or Zincalume steel roofing.
• Side Lap: The sideways overlap of one tile or sheet over another.
• Skillion: A roof with a single flat slope (Mono-pitch).
• Soaker Flashing: A hidden flashing used under tiles at a wall abutment.
• Soffit: The underside lining of the eaves (usually cement sheet or timber).
• Solar Fan: A roof ventilator powered by a small solar panel (e.g., Solar Whiz).
• Spalling: When the surface of a concrete tile or brick flakes off due to moisture expansion.
• Spreader: A section of downpipe that directs water from an upper roof onto a lower roof (must be designed carefully to avoid point-loading).
• Stormwater: Rainwater collected from the roof and ground drains (separate from Sewerage).
• Sump: A deep pit in a box gutter designed to increase water flow velocity into the downpipe.
• Swiss Pattern: A specific profile of terracotta tile with deep grooves.
• Terracotta: "Baked Earth." Natural clay tiles that are kiln-fired. They are glazed or unglazed and do not fade.
• Thermal Break: A material strip installed between metal roof sheets and steel purlins to stop heat transfer.
• Truss: A pre-fabricated triangular timber frame that supports the roof.
• Under-purlin: A heavy timber beam supporting the rafters mid-span to prevent sagging.
• Undertile Membrane: Another term for heavy-duty sarking.

• Valley: The internal "V" shape where two roof slopes meet and collect water.
• Valley Iron: The metal tray (usually zinc or Colorbond) sitting in the valley to carry water to the gutter.
• Vent Pipe (Stink Pipe): A sewer vent that protrudes through the roof to release gas.
• Verge: The edge of a gable roof.
• Water Course: The channels or grooves in a tile profile that direct water downward.
• Weep Hole: Small holes in bedding or brickwork to allow trapped moisture to escape.
• Whirlybird: A wind-driven turbine ventilator used to suck heat out of the roof cavity.
• Wind Clip: A metal clip used to secure cut tiles in valleys or hips to prevent them blowing off.
• Z-Flashing: A metal flashing shaped like a 'Z', often used at the junction of different materials.
• Zinc/Alum: A steel coating composed of Zinc (45%) and Aluminium (55%), known for high corrosion resistance (often branded as Zincalume®).