It’s true that not all flat roofs are suitable for ballasted systems, whether it’s because of structural limitations or the site’s location that prohibits this method. But this doesn’t mean it isn’t possible to still install solar PV to these roofs.
Instead, our Hook Plate system gives an alternative solution by mechanically fixing to the roof via a secure connection to the roof deck.
Not only does this method avoid lifting and placing ballast onto the roof, it also removes the necessity to fix into the roof’s main structure, which sometimes isn’t easy to locate during the installation.
We’re using traditional roofing techniques that are commonly used throughout the construction industry when vents or other ducting equipment are added to the roof. A secondary piece of the same roof covering is used over the top of the Hook Plate and hot welded to the existing to ensure a weather tight seal.
There’re instances where pitched roofs have been finished with a membrane or bitumen covering, making ballasted systems impractical because of the risk of the ballast sliding. Instead, we apply our Hook Plate solution to overcome this and make it possible to still utilise these roofs for solar PV generation.
On a cold roof, where the insulation sits below the roof deck, the Hook Plate fixes through the membrane or bitumen covering and into the deck below. This deck can be made from steel, timber or concrete, but this doesn’t affect the Hook Plate system as we’ll ensure you’re supplied with the most suitable screw depending on the deck material. With up to 8 fixing holes per Hook Plate, the system has a secure connection without disturbing the main structure.
It’s a similar process for a warm roof, where the insulation sits above the roof deck, except in this case we fix through all the layers into the roof deck. For these warm roofs it’s important to protect the insulation from any gaps around the fixings that can allow the heat to escape. This is why we supply thermal tubes to prevent this from happening. They sit within the fixing hole of the Hook Plate and seal the hole to stop heat from escaping.
The Hook Plate provides the possibility to either install the modules to the same pitch as the roof or to increase it to an optimum angle by using an elevated frame. We design and produce the elevated frames to suit each project’s requirements, so you’re sure to receive the best possible solution.
Each type of mounting rail that we offer has a different spanning capability according to its size and profile. We use this information in conjunction with other calculations to specify the most suitable mounting rail from our collection. We can even use a cross railing system, whereby there’s a primary base layer of rail with a secondary module rail layer applied over the top at right angles to each other. Not only does this help to strengthen the whole system but it also reduces the number of Hook Plates needed by around 50%, saving you on material and installation time.
So we’ve pre-assembled all the smaller components, so they’re ready to be simply slotted into the mounting rail profile.
Sunfixings Clamp XL fully assembled, Silver Mill Finish and Black Anodised are suitable for 32mm, 35mm, 40mm PV Module Thickness. For PV Module thickness beyond this range, Sunfixings offer alternative and complete Middle and End Clamp Mounting Solutions.