Decramastic Roofing Blog

By pennyroof, Oct 17 2018 01:35AM

When should I get someone to check my old Decramastic Roof?

Decramastic roofing tiles, also known as Decrabond or pressed metal tiles, were widely used in New Zealand during the 1970s and 1980s. Made of galvanised steel with a bitumen overlay, the tiles were known for being lightweight and easily installed. This very feature, however, makes the older tiles vulnerable to deteriorate over time, so maintenance and replacement are often necessary. If your home has an older decramastic tile roof from the 1970s and 1980s, repair or replacement may be a consideration. Here is a look at what causes such deterioration and the best ways to remedy the situation.


All roofing materials degrade over time but when the original decramastic tile roofs get older, the result can be far more unsightly. The surface coating and texture of many less expensive types of older tiles are believed to be highly vulnerable to changing temperatures. If your roof dates back to the 1970s and 1980s it’s recommended that you get a professional like Cooper Roofing to assess the old tiles before undergoing roof repairs or replacements.

Weather Damage

Driving rain, strong winds and direct exposure to New Zealand’s harsh UV rays combine over time to degrade old decramastic tile roofs, resulting in surface coating damage, dented tiles, loosened nails, chipped paint and cracks. While such damage is often repairable, basic patching techniques aren’t usually viable or recommended especially with older tiles.

Cracks and Dents

While walking on a roof is often justified during cleaning or repairs, decramastic tiles are easily cracked and damaged when subjected to such pressure. Unlike a dent in a vehicle, you can’t just pop a roof dent up to solve the problem. Older tiles are especially fragile due to having lost their original malleability. Attempting to pop up a dent may cause the tile to split, furthering the need for repairs or replacements. Modern decramastic tiles are far more heavy-duty and durable, so the chance of splitting in the future is no longer the issue it is with older tiles.

Organic Growth

Algae, lichen, moss, mildew and moulds easily grow on older decramastic tiles – resulting in the secretion of harmful acids that weaken the metal tile elements, causing leaks and a very unsightly, green-coloured growth on roofs. As the metal is eroded, rust can form on the surface which will be hard to detect because of various organic growths. Additionally, certain crawling and flying insects – which also cause damage – find such juicy growth delicious. These pests will be encouraged to make your roof their home causing further damage.

Replacing your Decramastic Roof

Your roof is obviously one of the structural elements of your home facing the most damage. It’s that part of a building that instantly and regularly comes in contact with weather components. The combination of extreme weather and temperature changes, dirt and other wind-borne elements leave an impact on roofing materials. Choosing between re-surfacing and a complete re-roofing job depends on the level of damage and deterioration to your roof.

Fortunately, the modern age of stone-coated Zincalume metal roofing is upon us, and an increasing number of homeowners opt to install and upgrade tiled or other roofing materials with new Gerard Roofs pressed metal roof tiles. Over time, metal roofs add lasting value to homes where other roofs may diminish in value. Here are a few examples of the advantages of Gerard Roofs tile roofing.

Life Expectancy

Unlike other roofing materials, the new generation of Gerard Roofs roofing tiles incorporate technologically-advances such as Zincalume protected steel, which gives tiles a longer service life than the old galvanised roofing tiles. The new generation metal tiles from from Gerard Rofos come with a 50 year pro-rata weather-proof warranty.

Variety of Styles

Coated metal roofs not only last longer, their very appearance has changed compared to old decramastic roofs. They are available in a variety of styles, in 32 colours and finishes, ensuring that you purchase a product that compliments your home perfectly.

Energy Efficiency

Efficiency is always a concern, so it always pays to research before going ahead with an order.The availability energy-efficient materials also ensures far less maintenance and overall weight on your home. Preserving the structural integrity of your home is always a foremost concern. Gerard roof tiles put less strain on the foundations and supporting beams.

Whatever you do…

Just because your roof is out of sight, it is still a vital component of your home – you cannot afford for it to be out of mind. If you’re in any doubt about your 1970s or 1980s decramastic roof please get Cooper Roofing to assess the old tiles before undergoing roof repairs or replacements. We will visit your property and give you a free assessment.

By pennyroof, Mar 27 2018 01:04AM

When you're living in a 73 year old Dunedin apartment building and the old terracotta roof is leaking, it's not ideal!

That was unfortunately the scenario for the 25 residents at 4 Alva Street. But thanks to a new Gerard roof, they can now all look forward to a worry-proof winter.

Age leads to problems for traditional terracotta roof

Built in 1945, the 8-unit dwelling is typical of the heritage architecture in Mornington, one of Dunedin's most historic suburbs with views over the city.

But the aging, heavy roof was causing a host of problems, as explained by Alva Street owner and the project’s lead co-ordinator, Rebecca:

"Like many roofs of that vintage in Dunedin, the original roof was Abbotsford terracotta tiles. The tiles had started to crack, and were deteriorating – causing more issues with leaks. It also had a lot of lichen on the shadier parts."

Faded, heavy, and leaking: the apartment's terracotta tile roof had seen better days. (Images courtesy Horizon Roofing)

New Gerard roof delivers weathertightness and improved safety

Led by Rebecca, the owners banded together, eventually deciding on a complete re-roof with Gerard pressed metal tile:

"We wanted a look that was closer to tile, and as a Body Corporate, we were looking for a long lasting, easy-care solution."

She says owners and residents are thrilled with the results:

"A big benefit is that it is waterproof, looks smart, and we hope that in the event of an earthquake, it will fare better than our old tile roof."

While everyone’s fingers will be crossed the city is spared in future, residents can be confident in their new roof. The lightweight resilience of an installed Gerard system delivers structural benefits by dramatically reducing the roof’s load, and has also been proven around the world to handle horizontal forces such like those caused by earthquakes.

Colour choice goes down to vote

The textured Gerard Tuffcoat roof has also lifted the building's appearance, not only for residents, but also neighbours situated further up Mornington’s hills.

Part of the aesthetic transformation was a switch in tone from the existing faded red clay, to Charcoal. But with Gerard Tuffcoat available in both traditional Terracotta and grey tones among others, Rebecca reveals that it was a close call:

"The colour wasn’t a unanimous decision, and nor was the texture. Getting agreement on the colour was probably one of the toughest parts of the project! The Charcoal (grey) had the biggest number of advocates. For those owners that preferred the Terracotta or another colour, there was a pragmatism that even if the colour was not their favourite, it was better to have a waterproof Charcoal roof than the (existing) leaky terracotta roof."

By pennyroof, Jan 22 2018 12:05AM

For the older generation“decramastic tiles*” means a scallop-shaped metal tile roof coated with stone chip. The issues that were often attributed to the product have, by some, continued to be associated with the new generation of acrylic, stone chip, metal tiles manufactured today.

The reality is they are totally different products and processes.

The issue of stones coming off the Decramastic roof surface was brought to public attention in 1978 in the NZ program “Fair Go”. What the public was not made aware of was the product in dispute was 15 years old and already superseded by a superior product. Nor were they generally aware that the manufacturer was successful in bringing a defamation claim against the broadcasters for misleading and incorrect statements.

Unfortunately this television program meant the general population became concerned about chip loss on metal tile roofs. But in testimony to the protective nature of the product there are still many of these roofs in service today, 50 years later, that have or can be restored with modern technology.

The idea of the chip coating came from an Englishman, Ben Booth, who developed a process for coating steel sheet with Bitumen onto which sand or grit was applied to prevent the sheets sticking together when stacked. It has been suggested that this was also to reduce glare as a form of camouflage during the wartime period around 1940.

Metal tiles made using this basic coating process were made from the late 1950s on. The first tiles were made in 1957 after Lou Fisher acquired Martile from the Martins.

In 1976 AHI Roofing initiated a major research program with the then modern technology of acrylics. By 1980 the new acrylic based product had replaced the barrier system which used the old Bituminous emulsion. These metal tiles were marketed under the brand Decrabond and New Harveytile.

In 1989 the largest installers of steel roofing tiles in Auckland engaged an engineer and chemist to develop what was to become Metrotile.

Today there are numerous manufactures of pressed metal tiles; Gerard Roofing, Metrotile, Metalcraft Roofing and others. All use similar technology, with some variations in formulation, and none use bituminous products in their manufacture.

Today’s pressed metal tiles use ZINCALUME® as a base with an acrylic coat over laid with natural stone chip with a second coat of acrylic overglaze.

The stone chips used today are similar to the originals with some synthetically coloured chip blended to offer a wider choice of colour combinations.

The range of tile profiles offered in today’s market is extensive. From the traditional to low profile slate and shake products.

While there is some differences between the warranties offered by products and brands most offer a 50 year pro rata warranty.

Cooper Roofing are a proud Gerard Roofing certified roofer, and we offer the full range of Gerard Roof tiles.

Todays tiles are not Decramastic
Todays tiles are not Decramastic
Todays tiles are not Decramastic
Todays tiles are not Decramastic
Todays tiles are not Decramastic
Todays tiles are not Decramastic
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