Flat roofs are the classical roofing solution, most commonly used on garages, carports and homes. They originate from arid climates, where water accumulation poses little to no danger. With advancements in roofing technology, flat roofs became more adaptable, water-resistant and widely used all around the world.
Today, flat roofs can be made using a variety of materials and in an array of designs to fit any structure and purpose. Their longevity depends on the materials used, workmanship and regularity of maintenance. However, the most reliable and cost-effective flat roofs are made out of metal.
Types of Flat Roofs
Flat roofs can be roughly divided in four categories:
- asphalt ( Uncommon in Australia )
Each category has its own advantages and downsides.
Flat Asphalt Roofs
These roofs are typically made using layers of asphalt and asphalt-like material, such as tar. The build-up method used for asphalt roofs comes down to layering materials such as paper, tar, gravel and so on. Asphalt consists of fossilised organic matter. It is abundant in nature and has been used since antiquity for roofs but the method is now considered ancient, just like the asphalt itself.
It is unheard of for large commercial properties to use asphalt roofs but smaller, low-budget residential buildings may still prefer it. The maintenance is non-existent, with the roof lasting up to 15 years. Repairs are nearly impossible and it’s often much easier to just scrap the entire roof and start over. Asphalt is cheap, eco-hostile, has poor energy efficiency and may exhibit aberrant behaviour in cold climates. Typically due to the hassle of asphalt roofs in general, most people who have it will replace it with tin.
Flat Fibreglass Roofs
In most instances, fibreglass roofs are made out of laminate, a glass-reinforced plastic sheet. The single-ply fibreglass roofs are easy to install and last up to 30 years thanks to the weatherproof topcoat. These roofs are eco-friendly and come in a variety of light and dark shades for an aesthetically pleasing look.
There are several types of fibreglass laminates, each suited for a different budget. They are resistant to inclement weather but are vulnerable to punctures, such as by falling tree branches. Also, flashings must be flawless or leaks may form on the roof where HVAC, pipes and other fixtures protrude through the laminate. Other than that, the fibreglass roof is seamless and shows good resistance to fire and chemicals.
Flat Metal Roofs
Metal is unmatched by any other roofing material but there are still nuances in choosing the right type of metal. There are aluminium, steel, zinc, tin and copper, as well as alloy roofs, covering all budgets and offering a slightly different but always bold and imaginative look. They all come in a range of profiles that fit traditional and modern building styles.
Plain metal roofs can develop a patina, which is a protective layer that has a unique colour. If the patina is scratched, the metal will regenerate the patina to provide the same protection from the elements. Metal tiles can be coated with a stone layer to mimic the look of clay, which is particularly important for buildings in Spanish style. That does not enhance the durability but there are special paints for metal roofs that do. Metal roofs are no louder than any other type of roof, so there is no danger of incessant rain patter waking you up at night.
Flat Tile Roofs
Finally, flat tile roofs provide a rugged, earthy appeal to a building. They can be made out of concrete, asphalt, clay, terracotta, wood, natural slate or metal. Their appearance most often includes pastel hues and black or reddish streaks, giving the entire roof a weathered image. In theory, tiles can last up to 75 years but you’re likely to be needing some repairs much sooner, in which case you will have to deal with finding a matching tile set or installing jarring tiles that ruin the whole look.
Weight is the biggest disadvantage of tiles; they can crack as they’re being installed under the added weight of roofers. The underlying structure needs to be capable of bearing the load and the tiles have to be fastened properly or a stronger gust of wind will scatter them. Tiles are absolutely unsuitable for DIY roofing projects and should only be installed by experienced roofers.
Advantages of Metal Roofs
Metal Roofs can last up to 100 years & because of their longevity, most metal roofs are less expensive than asphalt shingles in the long term – Wikipedia
Compared to any other roofing material, metal has two unique advantages, the first of which is—it can be infinitely recycled. Metal roofs are often made out of recycled material and the scraps from a damaged roof are recyclable as well. The lifespan of a metal roof is around 50 years, provided it is regularly maintained. This generally involves regular inspection, cleaning and painting to spot for early signs of damage. When you decide to replace your metal roof, the old material can be salvaged and a part of your initial investment recouped.
The second unique advantage is that metals can be combined to create alloys, getting a fine-tuned mix of qualities across a range of products to suit all building designs and purposes. Whereas asphalt, clay and concrete tiles have only slightly improved from their original design thousands of years ago, metal roofs have been advancing by leaps and bounds with each decade. When new alloys get discovered and refined, roofers and property owners gain a whole new catalogue of opportunity.
Klip Lok Roof Replacement
Klip Lok roofs are designed for installation on roofs with an incline between 0–1 degrees. The name explains how it’s installed: instead of screws, the sheets are locked in place by clips from the underside. Roofers have long been wanting for a roofing system that would help them eliminate screws, since they represent tiny punctures where water contact can cause corrosion and Klip Lok seems to be the answer. However, there is a catch.
Klip Lok was used about 40 years ago and abandoned for no apparent reason, only to experience a recent upswing in popularity. As it turns out, Klip Lok is difficult to install and roofers need to tread as if on eggshells when installing it. The ridges on a Klip Lok sheet give it structural integrity after it’s been installed but standing on a pan between ridges during installation is likely to cause a depression where water can accumulate.
Troubleshooting Klip Lok Roofs
The solution for these installation woes is go for slightly thicker Klip Lok sheets and install additional purlins for support. Another major issue is that Klip Lok sheets are vulnerable to damage from poor fixture positioning. Any fixture going through a Klip Lok sheet must necessarily go through the ridge, not the pan, or you will be back to square one: depression that invites water accumulation.
To avoid the water damage going through the roof, we suggest using a dry pan flashing, which covers the exposed part of the flashing with a separate sheet of metal. The visual integrity of the roof remains intact, the fixture is protected and the water just slides off. Remember that Klip Lok sheets shouldn’t be installed using drills or screws, so as soon as you see either, abort operation and dial our number.
Colorbond and Zincalume
Two of our favourite metal roof alloys are Colorbond and Zincalume. Colorbond is a pre-treated corrosion-resistant steel alloy that comes in 22 colours, with the ability to mix and match different ones for fascia, down pipes and gutter. All colours are thermally efficient, allowing for high heat reflection and dissipation.
Zincalume is a mix of steel, zinc and aluminium, with a scratch-resistant coating applied during the manufacturing process. The Australian manufacturer of both alloys announced a maximum 36-year warranty for all Zincalume products, with some warranty available for waterfront environments.
Colorbond colours for your home
Choosing the right colour when it comes to your home and your metal roof can be hard, this is why Colorbond presents colours in 5 different groups, Contemporary, Matt finish, Classic, Ultra, and of course Fencing colours.
Resources for Zincalume Steel from BlueScope
Below is further information in regards to Zincalume Steel made from BlueScope and its Compliance Specification Data Sheet.
The market is filled with Innovative roofing designs, such as Skillion roofs. It is defined as a minimalistic, flat roof with only one surface. The steep incline makes water run off quickly and an advanced Skillion design with two downward converging surfaces makes it possible to collect rainwater. They are easy to install and maintain, though they suffer more during sustained gusts of wind.
Low Pitch Roofs
Not all flat roofs are perfectly flat. Any roof with an incline between 1-5 degrees is considered a low pitch roof. They are some of the most vulnerable roofing solutions when it comes to leaking. Overlapped sheets are especially vulnerable to moisture and can leak because of the capillary effect, which is a curious property of water to defy gravity and get sucked up into the roof through minor cracks. The waterproofing needs to be meticulous and thorough to prevent leakages.
Low pitch and flat metal roofs are often used in architectural homes and commercial applications such as warehouses. On larger projects, sometimes roof sheets can require significant manpower or a crane to be lifted. Overlapped sheets are against building costs.
If you’re interested in getting a brand-new flat metal roof, get in touch with us and tell us your needs and ideas. We’ll chat until we reach a meeting of the minds and then plan out a wonderful, functional and beautiful roof for your home!