Driving around the streets of Melbourne, you’d be forgiven for thinking you need to have a pitched roof to install home solar solutions. But don’t worry! Flat roofs are just as good, and we at Sunstainable are experienced with the ins and outs of flat roof solar panel installation. It may surprise you to learn that the main difference between solar panels on pitched roofs vs solar panels on flat roofs are the racking systems. Let’s go through the details.
Quick fact: Flat roofs aren’t actually flat! Even “flat” roofs have a slight pitch to drain water away. As a result, solar panel systems won’t interfere with drainage.
Tilted Racking Systems
The Australian Standard for solar panel installation (AS5033-2014) recommends a tilt-angle within 10° of the latitude. While this is neither always achievable nor desirable, if you’re aiming for the highest energy conversion rate possible, then a tilted racking system will perfect the angle of your solar panels.
In terms of flat rooftops, tilted racking systems are a good solution to the lack of pitch. Tilting your solar panels allows them to capture the maximum amount of sun.
Within tilted racking systems there are a couple of options. The top three options are adjustable, motorised and fixed racks, and which one you choose will depend a great deal on the specifics of your roof.
As their names suggest, adjustable racking can be manually adjusted (fine if you have a rooftop area that you like to visit), motorised racking can be adjusted using a remote control or automated system, and finally fixed racking stays in the position it was installed in.
The benefit of a tilted racking system is that it overcomes the shallow pitch of a flat roof. The downside is that tilted solar panels cast shadows, so you can’t put rows of solar tilted panels together.
Ballasted Racking Systems
If you have a flat roof with a low pitch and high load bearing, then you might want to consider a ballasted racking system for your solar panels. Ballasted racking uses weights – usually concrete blocks – to hold down the frame. This reduces the need for fasteners, screws and bolts being put into your roof, which helps to protect its structural integrity.
Another benefit of ballasted racking systems is that they’re quick and easy to install, with less labour involved, and typically less maintenance, since there are no or fewer holes that need to be waterproofed.
The only caveat is that you need to have the exact right kind of roof to support this kind of racking system. You’ll need to get the load bearing of your roof properly assessed to make sure a ballasted racking system won’t be too heavy. <body>
Fixed Racking Systems
Fixed racking systems (also called attached racking systems) are the alternative to weighted ballasted racking. Fixed racking systems are secured using mounts that are attached to the roof with fasteners such as bolts and screws. This requires drilling and more installation time then ballasted racking, but once the process is complete, fixed racking systems are incredibly secure and won’t move even in the harshest winds. So long as all the mounts and holes are waterproofed you won’t suffer from leaks and expensive maintenance down the road. <body>
How Do I Decide?
Flat roofs do need to be carefully assessed when it comes to solar panels, but they’re unlikely to pose a problem.
The main thing to work out, together with your solar system installer, is which racking system is going to work best for your needs. You should also ensure that you get a professional structural engineering review of your roof, to ensure that your roof can handle the extra weight. At Sustainable we provide a structural engineering review as part of our service, to ensure you get the best possible result.
Installing solar panels on a flat roof is completely possible and is likely to be one of the best things you do for your future savings and home value.