RoofTG
New Zealand-based manufacturer of stone-chip-coated pressed steel roofing tiles.
Last updated August 31, 2026
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Overview
RoofTG is a New Zealand roofing-materials brand and manufacturer historically known as AHI Roofing. It produces pressed steel roof tiles and related roofing systems finished with protective coatings and natural stone chips. The company is associated with the Gerard and Decra brand names and has developed an international business serving residential, commercial, and construction markets. The business originated in Auckland in the late 1950s, when L. J. Fisher developed a pressed steel roofing tile using a galvanized steel substrate and a bituminous coating. The work followed experiments in New Zealand with coated metal roofing panels during the mid-1950s. Fisher established L. J. Fisher & Co. in 1957, and the resulting product is described as the first steel roof tile of its type. Natural stone chips were initially used for practical reasons: they helped prevent coated panels from sticking together during transport. Their appearance and texture subsequently became important selling features, while the coating and granular surface also contributed to weather protection and durability. The company expanded its product engineering during the 1960s and 1970s. It developed additional interlocking and multi-pan profiles, refined the stone-chip finish, and added protective overglazes. The business began exporting to Europe in the 1970s and later expanded into Asia, North America, the Middle East, and other regions. Licensed production arrangements helped extend manufacturing beyond New Zealand, including facilities or operations connected with Belgium, Denmark, Malaysia, and the United States. Its coated steel technology was marketed for demanding climates, including Canada and Scandinavia. Corporate ownership changed several times. L. J. Fisher & Co. became part of Alex Harvey Industries in 1969. The roofing activity was later associated with Tasman Building Products and was renamed AHI Roofing in 1988. Gerard operations outside the United States were acquired in 1989, and a plant was established in California during the same period. Fletcher Building acquired the business in 2003, after which the operation continued as part of the New Zealand building-products group. A Malaysian plant formerly operated by a licensee was acquired in 2005, and a new Hungarian plant began operating in 2009. RoofTG’s technical proposition centers on lightweight, interlocking metal tiles that combine the structural advantages of steel with the visual character of traditional tile or slate roofing. Its manufacturing process uses steel protected with a zinc-aluminium alloy, acrylic-based coating systems, and crushed natural rock for the granular surface. The company’s product families have included Gerard and Decra, with profiles and finishes designed for different architectural styles and climatic requirements. The available reference material describes the business as operating in more than eighty countries during one phase of its development and later states that its products were sold in more than 120 countries. Because the current corporate presentation, ownership structure, and operating footprint are not fully documented in the supplied material, those figures should be treated as historical descriptions rather than precise current metrics. RoofTG’s documented identity remains that of an internationally oriented roofing-products manufacturer rooted in New Zealand industrial design and manufacturing.
History
RoofTG’s history is rooted in the development of coated steel roofing in New Zealand. During the 1940s, bituminous coatings were used in Britain to protect iron cladding on large buildings. In the mid-1950s, L. J. Fisher observed this type of coating process and explored how it could be adapted to a residential roofing product. The first coated metal roofing tiles made in New Zealand had been produced by Martile Roofing in Howick in 1956, using an aluminium-manganese alloy and a baked enamel finish. Fisher subsequently acquired rights to use the Martile profile and developed a related product made from galvanized steel with a bituminous coating. Fisher established L. J. Fisher & Co. in 1957 and manufactured pressed, coated, and stone-chip-finished roofing panels in Auckland. The natural stone chips were initially applied partly to stop panels from sticking together during transport. Customers valued the resulting texture and appearance, however, so the granular finish became a defining feature of the product. Fisher experimented with alternative materials such as crushed shells and brick, but natural stone became the preferred surface material because of its visual qualities and perceived durability. Product development continued through the 1960s. The company introduced a ten-pan Harvey profile in 1964 and developed an improved interlocking profile in 1967. During the 1960s and 1970s, it refined the size and application of stone chips and added an overglaze. In 1969, L. J. Fisher & Co. merged with Alex Harvey & Sons and the New Zealand operations of Australian Consolidated Industries, creating Alex Harvey Industries. The roofing business operated through AHI Roofing Pty Ltd and became the basis for the later AHI Roofing identity. International expansion accelerated in the 1970s and 1980s. The company exported to Europe and established licensed manufacturing relationships, including arrangements associated with Belgium and Denmark. It also expanded into Asia, with licensed Malaysian production beginning in the 1980s. Acrylic coating technology was introduced around 1980 to improve the adhesion and durability of the stone-chip finish. In the same broad period, the company launched Colortile in New Zealand and established a United States manufacturing presence in Corona, California, in 1989. Export offices and regional operations were subsequently established or reported in Canada, Australia, Central Europe, the Persian Gulf, Japan, Hong Kong, Turkey, Slovenia, Poland, and France. The business underwent a series of ownership and corporate-name changes. It was acquired by Tasman Building Products in 1988 and renamed AHI Roofing. Gerard operations outside the United States were purchased in 1989. The product portfolio expanded with CoronaShake in 1992 and Oberon in 1995. Zincalume steel replaced galvanized steel as the principal substrate from 1995, extending resistance to corrosion and weathering. Fletcher Building acquired the business in 2003. In 2005, it acquired a Malaysian plant previously operated by a licensee, and a new Hungarian plant began operating in 2009. The company’s products have been sold under the Gerard and Decra names. Its manufacturing model combines steel formed into tile-like profiles, zinc-aluminium protection, acrylic coating systems, and a surface layer of crushed natural rock. The resulting products are intended to offer a lighter alternative to some traditional roofing materials while retaining a textured, tile-like appearance. The supplied material identifies RoofTG as the successor or current identity of the former AHI Roofing operation, but does not provide enough current corporate information to describe present management, exact facilities, or current sales in detail.
- 2009
Hungarian plant began operating
[1]A new manufacturing plant began operating in Hungary.
- 2005
Malaysian plant acquired
[1]The company acquired a Malaysian plant previously operated by a licensee.
- 2003
Acquired by Fletcher Building
[1]Fletcher Building acquired the roofing business.
- 1995
Zincalume substrate adopted
[1]Zincalume steel replaced galvanized steel as the substrate, supporting improved product longevity.
- 1992
CoronaShake launched
[1]The CoronaShake roofing product was introduced.
- 1989
Gerard operations acquired outside the United States
[1]The company acquired Gerard operations outside the United States and established a plant in Corona, California.
- 1988
Renamed AHI Roofing
[1]After acquisition by Tasman Building Products, the roofing operation adopted the AHI Roofing name.
- 1980
Acrylic coatings introduced
[1]Acrylic coating technology was introduced to improve the performance and adhesion of the coated stone-chip surface.
- 1970
European expansion began
[1]The company expanded exports into Europe and developed licensed manufacturing relationships.
- 1969
Alex Harvey Industries formed
[1]L. J. Fisher & Co. became part of a combination involving Alex Harvey & Sons and Australian Consolidated Industries’ New Zealand operations.
Products and positioning
Durable, lightweight, architecturally styled metal roofing that combines pressed steel construction with protective coatings and a natural stone-chip finish.
Stone-chip-coated metal roofing · 1989
Gerard
Gerard is a principal product and brand family associated with the company’s pressed steel roofing technology. Its tiles use shaped steel protected by a zinc-aluminium coating, an acrylic-based finish, and a layer of crushed natural stone. The system is designed to provide the visual texture of conventional tile or slate roofing while reducing roof weight and supporting resistance to weather exposure.
Stone-chip-coated metal roofing
Decra
Decra is an international roofing brand used for coated, pressed steel roof tiles and profiles. The product concept combines interlocking metal construction with a granular natural-rock surface. Different profiles and finishes are intended to support residential and architectural applications in varied climates, while the metal substrate offers a lighter alternative to some traditional roofing materials.
Metal roofing
Colortile
Colortile was introduced for the New Zealand market during the company’s transition toward modern acrylic coating systems. It represented the use of colored, coated steel tile construction in a product designed to combine decorative choice with the company’s established pressed-metal and stone-chip manufacturing approach.
Shake-style metal roofing · 1992
CoronaShake
CoronaShake was launched as a shake-style roofing product using the company’s coated pressed-steel platform. Its purpose was to reproduce the irregular visual character of shake roofing in a lighter, manufactured metal format with a protective coating and stone-chip finish.
Metal roofing · 1995
Oberon
Oberon was added to the product range in the mid-1990s. It belongs to the company’s family of profiled, coated steel roofing products and reflects the broader strategy of offering several tile shapes and architectural appearances on a common corrosion-protected metal platform.
Brand decisions
2003
Acquisition by Fletcher BuildingM&ABackground
The roofing operation had already passed through several corporate owners and operated internationally under AHI Roofing and Gerard-related brands.
Action taken
Fletcher Building acquired the business.
Aftermath
The roofing operation became part of Fletcher Building’s building-products portfolio.
1995
Adoption of Zincalume steelGeneration changeBackground
The company sought to extend the service life and corrosion resistance of its roofing products.
Action taken
Zincalume steel replaced galvanized steel as the primary substrate.
Aftermath
The substrate change was described as extending product life and became part of the company’s modern roofing construction method.
1980
Shift to acrylic coating technologyGeneration changeBackground
Earlier products used bituminous or other coating systems, while the company sought better adhesion and durability for the stone-chip surface.
Action taken
The business introduced acrylic coatings into its roofing-tile production.
Aftermath
The change supported the development of more durable coated-metal roofing products for export and demanding climates.
Sources1 sources
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