Now and then, there are damaged span wires on greenings. Mostly, the brackets are affected, which are bent or torn off the wall at the highest point of the flexural buckling - load. This might be caused by a mistake in the realisation of the project, meaning deficient or bad mounting, but oftentimes the problem lies in the planning, or even in the construction of the brackets, which would be the responsibility of the respective manufacturer. These kinds of problems oftentimes occur not until the warranty period is exceeded, due to the slow growth of the plants… On this site, pictures of damages and their causes will be explained, and you will learn how FassadenGrün prevents damage on its own products.
Some span wire systems are only zinc-coated (galvanised) and rather designed for the interior: Mounted in the exterior, they might rust, soon. Such elements are hardly qualified for facade greening. But also stainless steel brackets can rust, for instance in the case of curtain systems. Oftentimes, discolourations occur because the respective stainless steel is not sufficiently rust-proof for the exterior.
If curtain systems, for instance, are used, which are designed for light loads only, static damage will be unavoidable. Due to the heavy load of a wall greening caused by storms, wet leaves, fruits and so forth, the brackets will soon be torn off. Even brackets, actually designed for metal bars, fail when clamping the cable, because the tension is much larger using cables instead of bars. Vandalism damage on the other hand, occurs especially on deficiently planned (horizontal) span wires due to the "climbing possibility" of a vandal.
In the case of climbing systems it is necessary to state their suitability for certain plants. FassadenGrün-systems are divided into five structures. With the help of the climbing plants site, an assignment to particular structures is possible, which prevents overloading.
Usually, tight cables should not be overgrown with climbing plants and become "strangled" because of this. Otherwise, a tension of about 500 kg (3 mm-cable), or 1.000 kg (4 mm-cable) can occur and destroy the brackets. FassadenGrün refers to the difficulty of the right climbing technique - meaning a parallel "stock arrangement" in the case of prone climbers (Chinese wisteria, bittersweet, knotweed). Please look at the respective site on climbing plants.
Span wires are multilaterally loaded. This starts with the pre-stress, later it is the load of the leaves, fruits, and stems which can reach 10 kilogramme per square metre and even double in case of wet leaves (after rain). Extreme loads of 50 kg/sq emerge from icing, from multiple glazes and wind pressure, especially in great heights and on corners of buildings. Many providers of span wires fasten the cables in such a way that in the case of load peaks (storm, icing, climbing, rebounding children’s balls, or the like) the abrupt, quite high tensions are transmitted into the brackets, compulsorily. If these brackets are rigid and do not "spring", they cannot hold the loads and are torn off, soon. Brackets from FassadenGrün are only slightly tightened by hand (without cable tensioner) and thus, are designed not totally rigid but slightly springy. All cross holders are equipped with an anti-slip protection, which means overloading is not completely, but only partially transmitted onto the brackets. The cables slip out slightly and can be tightened again.
Broad wall spacing operates like a lever and generates a high flexing buckling-load, which can bend or tear off the bracket. FassadenGrün states exactly, which bracket is maximally suitable for a certain wall spacing.
Often various problems occur: The emerging tensions in a span wire are underestimated, or not taken seriously, and the shanks are disconnected or tapered in the diameter, in the area of the highest flexing buckling-load, at the transition into the wall bend. Or the fastening in the wall is not sufficiently placed. Brackets from FassadenGrün do not have a shank disconnection, or tapering. With the help of strong plugs they will be deeply and safely fastened in the wall.