Capped off to perfection: alternative roofing products - Misc. NZ
Capped off to perfection: alternative roofing products

Capped off to perfection: alternative roofing products

Solar, green or cool—they're roofs, but not as we know them.

Words by ArchiPro NZ

Not one to follow the herd? Would rather dance to the beat of a different drum? Then you might want to explore your options for a roofing material that is not straight out of the ‘burbs.

Solar roofing options come in many forms including solar shingles, glass-on-glass solar modules and even solar laminates such as this product from Dimond Roofing.

Solar roofs: turning up the sun

Humans have long been harvesting the power of the sun, with recorded evidence of ancient Greeks and Romans using ‘burning mirrors’ to focus the sun’s energy to light torches for religious ceremonies as far back as 3 BC.

In 1839, French physicist Edmond Becquerel discovered the photovoltaic effect while experimenting with a cell made from electrodes in a conducting solution. The cell, he noted, produced more electricity when it was exposed to light.

Further discoveries over the ensuing decades led to the development of solar cells, as we know them today, by scientists working for Bell Labs in the mid-1950s but it wasn’t until the global oil shortage of the 1970s that solar technology gained popularity as a viable method of powering our homes.

Since then, solar panels have become mainstream and fairly ubiquitous, however one of the biggest criticisms levelled against them is they’re not particularly aesthetically pleasing and they’re not actually a replacement for a traditional roof. That is, until now.

Solar shingles

Tesla, possibly the world’s best known disruptor, announced in 2018 that it will begin production of solar shingles for residential applications. The announcement caused a sensation, however, several other companies had beaten them to the punch by more than a decade.

Solar shingles are panels containing photovoltaic cells that are designed to look and function like standard asphalt or slate shingles, thus making them much more aesthetically pleasing while still generating electricity.

Glass-on-glass solar modules

These panels, also known as frameless solar modules, consist of photovoltaic cells sandwiched between two layers of glass. While not strictly a roofing material, because of their low-profile, glass-on-glass panels can be installed on small-scale structures such as carports, conservatories and patios where they can discreetly generate electricity while serving the additional functionality of providing shelter.

Photovoltaic laminate (PVL)

Again, not strictly a roofing material in it’s own right but a viable alternative to regular solar panels for people not wanting to compromise the look of their roof. PVL is primarily used in conjunction with metal roofing and can be applied at the time of installation.

PVL comes in rolls measuring 348mm x 5910mm x 2.5mm and is adhered to the roofing surface before being connected to an inverter.

Once the sole domain of commercial projects, green roofs are now becoming more and more popular in the residential market.

Green roofs: it’s now easy being green

Green roofs, especially in the commercial sector, have gained popularity in recent years and are increasingly making the switch to residential applications. Like solar, green roofs have a long history with historians citing the Hanging Gardens of Babylon as the first example of a green roof.

One of the seven wonders of the ancient world, the Hanging Gardens of Babylon were built in what is now modern-day Iraq around 500 BC. The gardens were designed by King Nebuchadnezzar II for his wife, who was homesick for the green fields and flowers of her homeland. The gardens were grown over stone pillars and roofs which were waterproofed with layers of reeds and tar.

In more modern times, people such as the Vikings and prairie settlers of North America have used sod and grass to insulate their homes. By the early 1900s, Germany was beginning to build green roofs in earnest across its urban areas and today, has an estimated 13,000,000m2 of green roofs.

While we’re not up to that level here in New Zealand, we did get our first green roof building in 1995 and now have a number of companies throughout the country designing green roofs for the commercial and residential markets.

Planting a green roof has numerous benefits, especially in urban areas, since they help to moderate the heat effect caused by an excess of hard landscaping, as well as removing pollutants from the air. In addition, a green roof reduces the amount of rainwater runoff, provides additional cooling and insulation and, above all, thanks to its natural beauty, increases the aesthetic appearance of your house.

Lighter coloured roofs, such as this one, are termed 'cool roofs' for their ability to help mitigate energy costs and reduce the heat island effect felt in suburbs and cities.

Cool roofs: being cool has never been hotter

If the idea of installing a solar roof or a green roof sounds like too much hard work but you still want to stand out from your neighbours (and make an eco statement at the same time) then a cool roof may be for you. A cool roof is any roof made from a white or light-coloured roofing material—metal, tile, timber or whatever, it doesn’t matter.

The role of a cool roof is just as the name suggests, to cool things down. Studies have shown that cool roofs don’t absorb as much heat as darker roofs, which means lower internal temperatures and less reliance on artificial cooling. With 32 per cent of carbon emissions originating from electricity consumption, any reduction in demand is a good thing.

Similarly, cool roofs have the ability to lower the localised external temperature by mitigating the urban heat island effect. Areas with a high concentration of cool roofs have been shown to be cooler than areas with a high concentration of traditional roofs.

Lastly, decreasing the temperature of your roof can actually help to extend its life. Many roofing materials expand and contract during temperature fluctuations. A roof that maintains a more equal temperature by reflecting heat won’t be subjected to the same stresses as one that absorbs heat.

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