What to do about Ivy on walls
Ivy is a genus containing between 12 and 15 species of evergreen climbing plants. They are highly popular decorative vegetation because of their bright green, year-round foliage, fast growth and remarkable ability to climb up to 30m in height.
Ivy can damage structures
Ivy is notorious for causing damage to brickwork and wood. Its powerful roots (the very source of its climbing aptitude) drive into mortar and between timbers causing damp penetration and structural weakening.
Direct issues in timber structures relate to the growth of runners and trunks between joints. Eventually these joints will expand under the pressure of the growing plant, thus destabilising the entire structure.
Further to structural destabilisation, ivy roots allow damp to penetrate wood grain. This provides perfect conditions for fungus and wet rot.
Timber surfaces will usually be badly scarred after ivy removal requiring extensive sanding and redecorating.
Pre-1930s builders generally employed a much softer mortar mix that the modern standard. This makes older buildings (such as the one in this Building Survey) highly susceptible to damage from ivy. Often Building Surveyors will recommend that ivy be stripped off walls before the roots penetrate the mortar and cause deterioration and damp penetration.
In some cases, older walls have become so overgrown with ivy that the stability of the wall actually relies on the plant. In these cases, ivy removal can cause collapse. Thus, if ivy growth appears extensive, it is wise to employ a contractor to recommend and undertake the best course of action.
Modern construction uses a stronger mortar mix that, it is generally accepted, is impenetrable to the ivy’s probing roots. In this case, ivy can actually protect the wall by deflecting rain. This type of mortar is not ubiquitous and homeowners are again urged to seek the advice of a contractor who specialises in ivy removal before deciding what is best for their home.