Coast Flow Glossary
Plain-English definitions.
Every term Coast Flow uses in a quote — from AS3959 and BAL ratings to soffits, valleys and ember guard. No jargon, no fluff.
A
AS3959
The Australian Standard for construction of buildings in bushfire-prone areas. Sets the requirements for materials — including gutter mesh — used on BAL-rated homes.
AS3959 (Construction of buildings in bushfire-prone areas) is the national standard referenced by NSW planning rules. It specifies which materials and construction methods are acceptable at each BAL rating. For gutter guard, AS3959 requires non-combustible mesh with a maximum 2mm aperture, correctly sealed at valleys and roof-line junctions.
Related: BAL Rating, Ember Guard
B
BAL Rating
Bushfire Attack Level — a rating (BAL-Low, 12.5, 19, 29, 40, FZ) that measures the potential exposure of a property to a bushfire.
Bushfire Attack Level (BAL) is assessed for properties in NSW bushfire-prone areas. Ratings run from BAL-Low up to BAL-FZ (Flame Zone). The higher your rating, the stricter the construction requirements — including the type of gutter mesh, roof sealing and window materials permitted. Coast Flow installs AS3959-compliant systems for BAL-12.5 through BAL-FZ.
Related: AS3959, Ember Guard
C
Colorbond®
BlueScope's brand of pre-painted steel roofing and building products, available in a standardised range of Australian colours.
Colorbond® is the dominant roofing and gutter material in modern Australian homes. When installing gutter guard or ember mesh, matching the Colorbond® colour of your roof and gutters keeps the mesh visually invisible from the ground. Coast Flow supplies the full standard Colorbond® colour range.
D
Downpipe
The vertical pipe that carries water from a gutter down to ground level, a stormwater pit or a rainwater tank.
Downpipes are the single most common blockage point on a home's drainage system. A gutter clean isn't complete unless every downpipe has been flushed and confirmed free-flowing. Blocked downpipes cause gutter overflow even when the gutters themselves look clean.
Related: Stormwater, Gutter Cleaning
E
Ember Guard
AS3959-compliant, non-combustible mesh (typically aluminium or stainless steel, max 2mm aperture) that blocks bushfire embers entering gutters, vents and roof cavities.
Ember attack — not direct flame — destroys the majority of homes lost in Australian bushfires. Ember guard closes the gaps where wind-driven embers would otherwise lodge in dry gutter debris and ignite. Standard gutter guard is not always ember guard; only AS3959-compliant systems provide bushfire protection.
Related: AS3959, BAL Rating, Gutter Guard
F
Fascia
The horizontal board fixed to the ends of the rafters, to which the gutter is attached.
The fascia is the timber (or metal) board that closes off the end of the roof rafters and carries the gutter. It's what water damages first when gutters overflow — soft, blackened or peeling fascia is usually the visible sign of years of overflow. Once fascia rots, gutter replacement often becomes fascia replacement too.
Related: Soffit, Gutter Guard
G
Gutter Cleaning
The removal of leaves, seeds, dirt and debris from gutters and downpipes to restore free water flow.
A proper gutter clean includes hand-clearing debris from the gutter run, flushing every downpipe until water flows freely, checking valleys, and removing all debris from the property. On South Coast NSW homes, this is typically needed 2–4 times per year without gutter guard.
Related: Downpipe, Gutter Guard
Gutter Guard
A mesh system installed over gutters to stop leaves, debris and pests entering — and, when AS3959-compliant, to reduce ember entry during bushfires.
Gutter guard is a mesh laid across the gutter and clipped to the roof sheet, stopping debris and pests entering while allowing water through. Quality systems are Australian-made aluminium mesh, colour-matched to the roof, sealed at valleys and hips, and carry long product warranties. Ember-rated variants also comply with AS3959 for bushfire zones.
Related: Ember Guard, AS3959, Gutter Cleaning
R
Rainwater Tank
A tank that collects roof runoff via gutters and downpipes for garden or household use.
Rainwater tank water quality depends heavily on what's in the gutters. Gutter guard, first-flush diverters and periodic tank cleaning all reduce sediment and debris entering the tank. Coast Flow recommends any homeowner on tank water clean gutters before every wet season.
Related: Gutter Guard, Downpipe
Roof Soft Washing
Low-pressure roof cleaning that uses biodegradable cleaning agents to lift moss, lichen and grime without damaging tiles or paint.
Soft washing is the safe alternative to high-pressure roof cleaning. It uses low water pressure combined with cleaning solutions that kill moss and lichen at the root, so growth doesn't return as quickly. Safer for tiles, Colorbond®, painted surfaces, solar panels and skylights.
Related: Colorbond®
S
Soffit
The underside of the eaves — the horizontal board between the wall and the fascia.
Soffits (also called eave linings) close the space under the roof overhang. Discoloured or bubbling soffits usually indicate water is escaping the roof cavity or gutter line. Ember-rated venting through soffits requires AS3959-compliant mesh in bushfire zones.
Solar Panel Bird Proofing
A perimeter mesh system that seals the gap between solar panels and the roof, preventing birds nesting underneath.
The gap under solar panels is prime nesting real estate for pigeons, starlings and cockatoos. Bird proofing mesh clips to the panel frame (no drilling into the panel) and closes the perimeter. Prevents panel shading, cable damage and gutter blockages from nesting material.
Stormwater
The rainwater collected by gutters and downpipes and directed into a piped drainage system, absorption pit or street kerb.
Blocked stormwater lines cause overflow at ground level — pooling around footings, undermining paths, and eventually cracking walls. Coast Flow clears blocked stormwater drains with a jetter and CCTV inspection where needed.
Related: Downpipe
V
Valley (Roof Valley)
The internal angle where two roof planes meet, which channels water into the gutter.
Roof valleys are the highest-flow water paths on a roof. They're also common leaf-trap points and, if not sealed correctly, common leak points. Any gutter guard install must include correct valley sealing — either mesh continued into the valley or an appropriate valley tray fitted.
Related: Gutter Guard
Protect your home with Coast Flow
Honest advice, quality workmanship and reliable local service from a family business based in Berry. All gutter protection systems are available in Colorbond® colours to match your roof and gutters.