Building damages caused by ivy and other climbing plants is a less than fun topic, though a necessary one to address. Here you'll find out which problems may occur in façade greenings and how they can be prevented. Potential structural damage is always related to the growth characteristics of the climbers. We differentiate between three 'damage groups' (DG):
DG 01 - Self-clinging climbers: These plants attach to virtually any surface via aerial rootlets/shoots (some with additional adhesive pads). They are: ivy, climbing hydrangea, some trumpet vines, Boston ivy and Virginia creeper. Remnants of these aerial rootlets and adhesive pads can sometimes lead to building defects or damages.
DG 02 - Negatively phototropic plants ("light fleeing" plants): In these plants, some shoot tips grow away from the light into gaps and crevices, where they can cause damage. All self-clinging climbers (DG 01), and potentially all vigorous twiners (DG 03), grow occasionally away from light.
DG 03 - Twiners or lianas: Twining plants with a vigorous growth habit (wisteria, silver lace / Russian vine, bittersweet) cause tensions which can eventually strangle structures or force structures apart by growing through or behind them.
Image 01: Remaining adhesive pads after removing plant shoots (DG 01). On intact surfaces these adhesive pads remain stuck, which means that before repainting the surface they have to be singed off. To prevent such problems it is best to avoid using self-clinging plants.
Image 02: Here the ivy was cut back and in the process of removing the branches some aerial rootlets remained stuck to the wall (DG 01).
Image 03: In emulsion paintwork or in already damaged surfaces the paint or mortar can pull off or break off respectively.
Image 04: Two ivy shoots are getting into the gaps of a wall-cladding (DG 02). The lower shoot has already loosened the cladding, which is obvious by the dark gap. The shoots of negatively phototropic plants can also grow into shutter boxes and vent holes, etc.. where their vigorous girth growth can force apart loose building structures. It is therefore recommended not to use such plants on vulnerable walls.
Image 05: This freely moving, long wisteria shoot has found a dark crevice in the wall-cladding of a winter garden, into which it will grow and most likely force the plank off. It is therefore recommended to leave ample space between the trellis system and any walls at risk. Usually a distance of 0.5 - 1m is sufficient; for vigorous twiners, allow 2m.
Image 06: This Boston ivy is searching for gaps on a wooden roof eave (gutter). It will probably grow into the gaps, grow aerial rootlets in-between the individual roof sheetings, and eventually emerge on the roof again (DG 02). It has been observed, for example, on an unrefurbished old villa how a Virginia creeper (P. quinquefolia) found its way from below through the crumbly paving slab of a balcony, only to emerge at the top of the balcony floor. It just shows the incredible force with which these plants can push through obstacles. Many types of sealing sheets/strips are at risk of being "grown through" and losing their sealing function, because specifically root-resistant roof sheetings are only specified in the case of roof greening projects.
Image 07: Here shoots of an ivy have grown behind the slate cladding; some slate tiles have already been broken from the pressure of the ivy's girth growth (DG 02).
Image 08: The edge of this roof has been damaged by ingrown shoots (DG 02).
Image 09: Wisteria shoots have grown into the open joints on this wall (DG 02), whereby the lower natural stone slab has already been significantly pushed aside, which is obvious by the enlarged width of the gap. With further growth, the slabs can be forced out and then fall down.
Image 10: A "strangled" downpipe after removing a wisteria shoot (DG 03).
Image 11: Even trellis systems can be prone to damage. In wire ropes especially, distension can lead to wall bolts being torn out (DG 03). FassadenGrün therefore recommends having vigorous twiners on wire rope systems only if parallel stem training -without permanent twining- can be ensured, as is described for wisteria.
Image 12: Apart from damages caused by twining (DG 03), very vigorous plants can become a risk by forcing themselves into gaps and by growing behind building structures. Without proper care and lack of pruning, huge masses of foliage can develop, which can scrape susceptible walls (WDVS/EWIS) during windy weather. In this image, however, the plant was growing behind the fastenings of the downpipe, forcing them off the wall, thus breaking the connection with the upper tilted part of the downpipe.
Image 13: Vigorous growth (DG 03) is always linked with strong foliage development. Branches and leaves overgrowing the eaves can block the roof drainage. The wall area to the left is very wet after a rainfall. Most likely, the gutter has been blocked by the foliage of that huge trumpet vine. If the gutters are blocked/clogged and/or the inlet filters are covered, the gutters will overflow during heavy rain and the walls may become soaked. Drying out such damages can take months and is often linked with mildew development on the internal walls. Continued and repeated drenching over the years can even lead to fungus damage ("dry rot") on ceiling beams.
Image 14/15: Climbing plants don't belong on roofs or wall copings! They can lift off roof tiles and grow through sealing sheets (geomembrane sheets) (DG 02). Driving rain or snowdrifts means a 'water march'-- 'go, water, go!' for potential leaking spots -- every home owner's nightmare. Hence: always strictly separate roof and façade greening!