When it comes to concealed fix roof sheeting, Safintra’s sheet/clip interface is the epitome of strength and integrity
Concealed fix roofing is the most sought-after roofing system on the market, not only for its proven functionality even at very low slopes, but also for its durability and sustainability.
At the heart of the system’s performance is the design of the clip holding down the sheet, and the integrity of the interface between clip and sheet. The closer the sheet/clip interface, and the stronger the clip holding it onto the substructure, the stronger the entire system.
Globally, weather patterns have become more violent and SA is no exception. With this in mind, Safintra South Africa has invested considerable resources in the engineering, design and manufacturing of stronger clips for its widely used Saflok system.
After launching the re-engineered Saflok 700 clip in 2017, the company is pleased to unveil its new Saflok 410 clip, which has delivered outstanding results in wind uplift tests, making it the strongest roof clip on the SA market.
Central to all product innovations in concealed fix designs is the ability of the clip to withstand the forces exerted by wind, which is the most common reason for system failure.
Contrary to popular belief, damage is not generally the result of wind being caught underneath the sheet and forcing it off, but rather due to the strong suction (negative pressure) that is created on the outer surface of the sheeting when the wind blows over the roof. This negative pressure can lift the sheet up, and could physically force it off the clip.
Eaves and exposed overhangs are particularly vulnerable, as it is at these points that the roof endures a combination of negative suction above the roof and positive pressure caused by wind blowing underneath the eaves. These combined forces can disengage the sheet from the clip.
For this reason, purlin spacings on the overhangs are reduced, to increase the hold-down intervals required to cater for the doubled wind forces it endures.
The most common failure point for a roof clip is the ‘goose neck’, which will take on the most pressure when high wind conditions are experienced, especially on the gables and eaves. It is essential for the clip to have a very sturdy goose neck in order for it to withstand increased wind loads.
The new Saflok 410 clip has deeper embossing for rigidity to allow for greater hold-down capabilities. The embossing has also been designed to run up the goose neck and over the male rib to interlock more efficiently.
The fastening of the clip to the purlin is also very important. A tail has been added to the 410 clip to allow for an additional fastening point onto the purlin. This increases its hold-down capabilities and also strengthens the anchor, which engages with the centre rib of the sheets. The tail minimises rotation on the anchor of the clip, thus giving it more rigidity. It also ensures that the anchor will maintain its linear integrity during installation, preventing the clip from being distorted.
The Saflok system has performed outstandingly on millions of square metres of roofing in Southern Africa and is setting the bar even higher to stay ahead of changes in climatic conditions.
After all, if there’s one thing that should not be a concern, it’s the sheeting that protects the building and its valuable contents from the forces of weather.