Roofing Materials
- Asbestos-Cement RoofingRoof sheets and slates made of cement reinforced with asbestos fibres, widely used in the 20th century and now banned in many countries as a health hazard.
- Colorbond SteelColorbond is an Australian prepainted steel product line made by BlueScope, first produced in 1966 and ubiquitous on Australian roofs.
- Concrete Roof TileA roof tile moulded from sand, cement and pigment; a heavy, economical alternative to clay made in many profiles worldwide.
- Corrugated Iron (Corrugated Galvanised Iron)Corrugated iron is sheet metal rolled into parallel waves for stiffness; patented in 1829, it became a defining roofing material of farms, colonies and industry.
- Interlocking Clay TileA pressed clay roof tile with grooves on its sides and head that lock into neighbouring tiles; the French or Marseille tile is the classic form.
- Palm and Grass ThatchThatch made from palm fronds, leaves or tropical grasses, used for traditional and resort buildings across tropical Africa, Asia, the Pacific and the Americas.
- Sago Palm ThatchRoof thatch made from sago palm (Metroxylon) leaves, used across Melanesia; called natangura in Vanuatu.
- ThatchA roof covering of dry plant stems such as reed, straw, sedge, palm or grass, laid thickly so rain runs off the outer layer.
Roof Components
- Cold RoofA cold roof is a pitched roof insulated at ceiling level, leaving a ventilated, unheated loft or attic space between the insulation and the roof covering.
- Vapour-Permeable Underlay (Breather Membrane)A vapour-permeable underlay, or breather membrane, is a roof underlay that resists liquid water but lets water vapour pass, widely used in UK and European pitched roofs.
- Warm RoofA warm roof is a construction in which insulation follows the roof slope or sits above the deck, so the structure and roof space stay within the heated envelope.
Roof Shapes & Forms
Installation & Methods
- Australian WHS Roof Work RequirementsAustralian work health and safety codes require roof work fall risks to be controlled through a hierarchy, with edge protection and rules based on roof pitch.
- Through-Fastened Panel InstallationThrough-fastened metal panels are screwed directly through the sheet into purlins or decking with sealing washers, with side and end laps sealed against water.
- Tile BattensTile battens are horizontal timber strips fixed across the rafters or deck that set the spacing of tile or slate courses and provide their fixing point.
Standards, Codes & Testing
- National Construction Code (Australia)Australia's National Construction Code is the national set of minimum technical requirements for buildings and plumbing, published by the Australian Building Codes Board.
- New Zealand Building Code Clause E2 (External Moisture)Clause E2 of the New Zealand Building Code requires roofs and walls to resist the entry and build-up of external moisture; E2/AS1 is the main acceptable solution.
- NZ Metal Roof and Wall Cladding Code of PracticeThe NZ Metal Roof and Wall Cladding Code of Practice is the industry guide to designing and installing metal roofing in New Zealand, published by NZMRM.
Manufacturers
- BlueScopeBlueScope is a Melbourne-based steel company, demerged from BHP in 2002, whose brands include COLORBOND, ZINCALUME and LYSAGHT roofing steel.
- DECRA Roofing SystemsDECRA is a stone-coated steel roofing brand with roots in New Zealand in 1957, manufactured in the US at Corona, California.
- Fletcher BuildingFletcher Building is an Auckland-based building-materials group formed in 2001, which owns the Australian steel roofing maker Stramit.
- StramitStramit is an Australian maker of roll-formed steel roofing, walling, rainwater and structural products, part of Fletcher Building since 2005.
Organizations & Associations
- BRANZ (Building Research Association of New Zealand)BRANZ is New Zealand's independent building research organisation, established in 1970 and funded by a levy on building consents.
- How to Find a Licensed Roofer (by Country)A country-by-country guide to how roofers are licensed or registered, and where homeowners can check a contractor's credentials.
- Master Builders AustraliaMaster Builders Australia is the national federation of state and territory builders' associations, with roots over 130 years old and about 32,000 members.
- New Zealand Metal Roofing Manufacturers (NZMRM)NZMRM is the association of New Zealand metal roofing manufacturers that publishes the NZ Metal Roof and Wall Cladding Code of Practice.
- Roofing Association of New Zealand (RANZ)RANZ is New Zealand's national roofing trade association, whose vetted members follow a Code of Practice for workmanship, compliance and conduct.
History of Roofing
- Budj Bim Stone HousesRemains of Gunditjmara domed houses with basalt walls in the Budj Bim World Heritage landscape of south-west Victoria, Australia.
- Global Spread of Corrugated IronHow corrugated galvanised iron travelled from Britain to colonial Australia, Africa, the Americas and Asia, becoming one of the world's most common roofs.
- History of Asbestos Cement RoofingAsbestos cement sheets and slates, patented by Ludwig Hatschek in 1900 and sold as Eternit, roofed buildings worldwide until health risks led to bans.
- Jørn UtzonDanish architect (1918-2008) who designed the Sydney Opera House, with its tiled shell roofs, and won the Pritzker Prize in 2003.
- Raupo Houses OrdinanceNew Zealand’s first building law (1842), which taxed raupō and thatched buildings in towns to reduce fire risk.
- Sydney Opera House RoofThe shell roofs of the Sydney Opera House, built of precast concrete ribs and panels and clad in 1,056,006 Swedish-made ceramic tiles.
Roofing Around the World
- Fijian BureTraditional thatched Fijian house on a raised rock base with a steep hipped roof; once a men’s house, now also a resort bungalow.
- GunyahAboriginal Australian shelter of bark, branches, leaves and grass, also called humpy, wurley, mia-mia or wiltija; often domed or a lean-to.
- Haus TambaranSepik spirit house of Papua New Guinea: a men’s ceremonial house with a towering painted gable and a thatched roof sloping to the ground.
- ManeabaThe great pandanus-thatched meeting house of Kiribati, built of coconut wood and coral without nails; the centre of village governance.
- NakamalTraditional meeting house of chiefs in Vanuatu, a centre of kastom governance, anecdotally built to withstand cyclones.
- Palauan BaiPalau’s traditional men’s meeting house, with a tall decorated gable and steep thatched roof, built without nails on a stone platform.
- QueenslanderTimber house type of Queensland, Australia, raised on stumps with verandahs and a corrugated iron roof, built from the 1840s.
- Roofing in AustraliaAustralian roofing: Aboriginal bark and stone-walled shelters, colonial bark and shingles, then corrugated iron, tiles and coated steel under the NCC.
- Roofing in FijiFijian roofing: steep thatched bure and vale on raised bases, now almost entirely metal sheet, tested by Cyclone Winston in 2016.
- Roofing in KiribatiKiribati roofing: pandanus-thatched maneaba meeting houses and homes on coral atolls; thatch still covers over half of household roofs.
- Roofing in MicronesiaRoofing in the Federated States of Micronesia: thatched faluw and houses, Nan Madol’s basalt city, and today mostly metal or concrete roofs.
- Roofing in NauruNauru roofing: a phosphate-era housing stock of metal roofs on concrete or board walls, with roof gutters feeding household water tanks.
- Roofing in New ZealandNew Zealand roofing: Māori lashed timber and thatch, colonial raupō, shakes and iron, then profiled steel, tiles and post-leaky-building rules.
- Roofing in PalauPalauan roofing: the steep, decorated bai meeting house thatched with pandanus or nipa palm, and modern metal and concrete roofs.
- Roofing in Papua New GuineaPNG roofing: steep thatch of palm leaf, pandanus or grass on lashed frames, towering Sepik spirit houses, and a shift to metal sheet.
- Roofing in SamoaSamoan roofing: the open-sided fale with a domed thatched roof lashed with sennit, now largely roofed with corrugated iron.
- Roofing in the Marshall IslandsMarshallese roofing: pandanus-thatched roofs on four posts with a rat-proof loft, largely replaced by galvanised and aluminium sheet.
- Roofing in the Pacific IslandsOverview of Pacific Islands roofing: thatched timber buildings lashed with sennit, largely replaced by corrugated metal, built for cyclones.
- Roofing in the Solomon IslandsSolomon Islands roofing: sago-palm leaf thatch on timber frames, now mostly corrugated iron, with thatch still common in villages.
- Roofing in TongaTongan roofing: lashed fale structures survive mainly in churches and halls; nearly all homes now have metal roofs, tested by Cyclone Gita.
- Roofing in TuvaluTuvalu roofing: atoll houses and maneapa meeting halls once thatched, now overwhelmingly corrugated iron with gutters feeding rainwater tanks.
- Roofing in VanuatuVanuatu roofing: natangura sago-palm thatch and nakamal meeting houses alongside corrugated iron, both battered by Cyclone Pam in 2015.
- Samoan FaleOpen-sided Samoan house with a domed roof on timber posts, traditionally thatched with sugarcane leaves and lashed with coconut-fibre sennit.
- WharenuiThe Māori meeting house at the heart of a marae in New Zealand; its gabled roof structure represents the body of an ancestor.
Climate, Hazards & Sustainability
- Bushfire Attack Level (BAL)Australia's rating of a building site's bushfire exposure, from BAL-LOW to BAL-FZ, which sets construction requirements including roofing.
- Earthquakes and RoofsHow roof weight, attachment and bracing affect building performance in earthquakes, and why heavy tile roofs on weak frames are a known risk.
- Ember-Resistant Roof DetailsRoof vents, gutters, closures and edges designed to keep wind-blown embers from igniting debris or entering the building during a wildfire.
- Hail Damage to RoofsDamage caused when hailstones strike roofing: bruising and granule loss on shingles, cracked tiles and slates, dented metal and punctured membranes.
- Hurricane Roof DamageHow tropical cyclones (hurricanes, typhoons and cyclones) damage roofs, from lost coverings and edges to deck blow-off and wind-driven rain.
- Hurricane TieA metal strap or clip that fastens a rafter or truss to the wall to resist wind uplift; also called a hurricane clip or hurricane strap.
- Rainwater Harvesting from RoofsCollecting rain that falls on a roof for storage and reuse, and how the roof material affects the quality of the collected water.
- Roof Wind Pressure ZonesAreas of a roof (field, edge, corner) assigned different wind design pressures because suction is strongest near edges and corners.
- Roof-to-Wall ConnectionThe joint that fastens rafters or trusses to the top of the walls; a key link in the load path that keeps a roof on in high winds.
- UV and Heat Degradation of RoofingHow sunlight and heat break down roofing materials over time through photo-oxidation, embrittlement, chalking and loss of protective surfaces.
- Wildfire RoofingRoof design and materials that reduce the chance of a building igniting from embers, radiant heat or flames during a wildfire or bushfire.
Problems, Repair & Maintenance
- Leaky Homes CrisisNew Zealand’s weathertightness failure affecting timber-framed buildings built 1988-2004, estimated in 2009 to cost about NZ$11.3 billion.
- Ridge Repointing and RebeddingRenewal of the mortar that beds and seals ridge and hip tiles; in the UK, current standards also require mechanical fixing of these tiles.
- Roof MossMoss growth on shaded, damp roofs that holds water, lifts shingles and tiles, and blocks drainage if left to build up.
- Zinc and Copper StripsMetal strips fixed near a roof's ridge whose rain runoff carries metal ions that discourage moss, algae and lichen below.