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Damage to Wire Rope Systems

The installation of a wire rope trellis on a facade is within the reach of every do-it-yourselfer. There are, however, potential pitfalls to be aware of to avoid damaging the cable system or the masonry. When a wall trellis is damaged, it is almost always the mounts which have been affected: they can be bent or torn out of the wall where the flexural buckling load is the highest. This might be due to errors during assembly (poor mounting) or due to a faulty design/construction of the mounts (attributable to the respective manufacturer), but most often it is due to a planning error. As a result of slow plant growth, such problems often do not reveal themselves until the warranty period has passed. Here you can read about possible damage, explanations of their causes, and protective measures FassadenGrün takes with our own anchoring and mounting systems.

Damage to cables and mounts caused by excessive weight
Damage to cables and mounts caused by excessive weight

Rust Damage

Some cable systems are only zinc-coated (galvanised) and rather designed for indoor use: if mounted outside, they soon rust. Such elements are hardly qualified for facade greening. But stainless steel mounts too can rust; for instance, in the case of curtain systems. Oftentimes, discolourations occur because the respective stainless steel is not sufficiently rust-proof for outdoor use. 

Inappropriate Tension Rope Systems

Using lighter/alternative rope tensioning elements (like curtain systems) which are designed for minimal loads only, structural damage is inevitable. Due to the heavy loads in wall greening caused by storms, wet leaves, fruits and so forth, the mounts will be torn out sooner or later. Likewise, mounts intended to carry a metal rod cannot carry cables; the tension load is much higher. Even mounts which are actually designed for metal bars will give out when clamping rope, because the tension is much higher using ropes instead of bars. Damage caused by vandalism, in turn, occurs when improperly planned (horizontal) tension ropes give a climbing possibility (a 'ladder') for a vandal.

(In)compatibility between Plants and Climbing System

Not all supports are suitable for all plants. A plant's habitus will determine which type of trellis is appropriate-- more or less close-meshed grids or cables arranged only verically, for example. At the bottom of each climbing plant profile, you'll find a table listing the shapes (and construction styles) of the cable systems that support the plant's optimal development; you'll also see which cable arrangments and shapes to totally avoid.

Incorrect Trellising Methods

As a rule, climbing plants should not be allowed to grow over and wrap around trellis cables. Vigorous twiners will strangle them, and the resulting tensile stresses of up to 500 kilograms (3 mm rope) or 1,000 kg (for a 4 mm rope) will destroy the mounts. FassadenGrün provides information on the appropriate trellising technique for each climbing plant- especially for voluble, intense twiners (wisteria, bittersweet, silver lace vine). Refer to the respective plant profiles.


Forced Transfer of Peak Loads: Unexpected Additional Weight

Tensioning ropes are multilaterally stressed, subjected to a variety of loads at different times. There is initial preload and later the load of leaves, fruits, and trunks can quickly reach 10 kilograms per square metre and even double in the case of wet leaves (after rain). In winter extreme loads of 50 kg / m² result from ice... that is, from multiple freezings and wind pressure, especially at higher altitudes and on corners of buildings. Most climbing trellis fasteners do not take these peak loads into account, the weight of which is borne entriely by the fasteners. Many providers of tension ropes fasten the ropes in such a way that the shock-like, very high tensile stresses are forcibly transferred to the mounts during peak loads (storm, icing, climbing or attempt at climbing, rebounding children’s balls, etc..). If these mounts are rigid and do not "spring," they cannot hold the loads and are quickly torn out. Mounts from FassadenGrün are only slightly pre-tensioned by hand (without turnbuckle) and thus, are not totally rigid but designed to be slightly springy. All cross mounts are equipped with an anti-slip protection, which means that overloads are only partially transmitted to the mounts. The ropes slip out slightly and can be re-tensioned.

Distance between wall and cables

The leverage effect and bending load on the wall mount increases with the length of the mount: that is, the anchor can be twisted or pulled out of the wall more easily the further it protrudes from the surface of the wall. Please observe the maximum protrusion allowance (wall distance) for our trellis fittings and mounts, which are indicated on the individual product pages.

Insufficient Wall Mounting

These are the problems that occur most frequently with faulty wall mounting: the tensile stresses arising in a tensioned rope are underestimated or not taken seriously; the shafts are interrupted or tapered in diameter and thus susceptible to buckling in the area of the highest bending buckling load, of the highest bending buckling load, i.e. when they are introduced into the wall; or, the anchoring in the wall is not sufficiently strong. Mounts from FassadenGrün do not have a shaft break (disconnection/interruption) or tapering, and with strong plugs, they will be fastened deeply and securely into the wall.

Inappropriate and unpractical (curtain) system: mount has been torn out and has rust marks.
Climbing plant support system -- damage
Unsuitable eyelets/plugs and too much wall distance, which causes the eyelet in the lower heavily-loaded rope to be pulled out
Structure eyelets
Too much wall distance; hooks are not screwed deeply enough into the rawl plugs.
Too much wall distance with this mount
Vandalism: In public spaces, cables should not be mounted horizontally in the lower areas (up to a height of about 2 m), due to the "climbing effect" provided to possible vandals.
Wire rope damage due to vandalism
Stainless steel mount with a galvanised (zinc-coated) metal plug that has rusted from the inside: the problem here lies with the damaged wall coping, through which water from the top enters the wall, soaks through, and corrodes the otherwise dry rawl plug.
Climbing plant support system with rust
A wall mount designed for rods (not for ropes) now loose due to risky planting (Chinese wisteria)
Wall mount: loosened fixture on wall console
Corrosion of a galvanised (zinc-coated) metal rawl plug caused by failure to seal the drill hole, fraying of the mount due to the forced transfer of load peaks
Corroded metal rawl plug
Corrosion on a zinc-coated wall mount
Corrosion on galvanised zinc plating
Too much wall distance; too weak a mount
Planning error
Overgrown by silver fleece vine and overstretched wire ropes, overloaded mounts.
Damaged tension rope
Putting horizontal ropes in the lower area of a wall trellis tends to be seen as an invitation to climb (for children or vandals); climbing will twist the anchors and slacken the cables.
Base area
Tensioned wire rope with high wall distance, forced transmission of peak loads
Tensioned-rope defect
Incompatibility between plant and climbing system, as well as wrong trellising method
Damaged tension rope
Mount ripped out as a result of incorrect trellising (vigorous wisteria allowed to wrap around the climbing aid)
Damaged wall mount