Ivy on My House Wall — Is It Causing Damage and Should I Remove It?

The older stone properties of Grange-over-Sands, Cartmel, Kendal and the surrounding villages of South Lakeland are frequently adorned with ivy, Virginia creeper and other self-clinging climbers. Some of this growth has been established for decades. Whether it is doing harm or not is a question we are asked regularly, and the honest answer is more nuanced than the definitive warnings you sometimes read online.

What Ivy Does to a Solid Stone or Brick Wall

On a solid, well-pointed stone or brick wall in good condition, established ivy is not causing structural damage. This is a point that surprises many people but it is well supported by the research on the subject. Ivy attaches itself with small adhesive roots that grip the surface of the masonry but do not penetrate into sound mortar joints or solid stone. On a structurally sound, well-maintained wall, ivy provides several benefits: it insulates the wall, reducing heat loss; it provides a buffer against wind-driven rain, reducing the amount of moisture penetrating the wall face; and it cools the wall surface in summer, reducing thermal stress on the mortar.

Historic England has reviewed the evidence on ivy and historic buildings and their conclusion, published in their guidance on the subject, is that ivy on solid walls in good condition is generally not harmful and may be beneficial. This is relevant to the many older stone properties across Grange-over-Sands, Cartmel and South Lakeland where ivy has been established for generations without apparent harm.

When Ivy Does Cause Problems

The situation changes significantly when the underlying wall is in poor condition. Ivy stems and roots will exploit any existing crack, failed mortar joint or loose stone. Once ivy has entered a crack or a failing joint, the growth within the crack over subsequent years can widen it, accelerating deterioration. Ivy in this situation is making an existing problem worse, not causing a problem where none existed.

The other situation where ivy causes genuine problems is when it reaches the roof. Ivy that has grown up and over the eaves and is growing under roof tiles, into gutters, or into any gap in the roof structure, can cause significant problems. Ivy under roof tiles lifts them, potentially allowing water ingress. Ivy in gutters blocks drainage. Ivy growing around chimney stacks can penetrate the pointing and mortar at the tops of stacks, which are often the first part of an older property to need repointing.

Window frames, particularly timber frames, can be affected by ivy growing around them, retaining moisture and encouraging rot in the timber.

How to Tell Whether the Wall Beneath the Ivy is in Good Condition

The most practical way to assess this without removing all the ivy is to lift sections away from the wall at various points and look at the masonry beneath. If the pointing is intact, the stones or bricks are sound, and there are no obvious cracks or voids, the wall is likely in good condition and the ivy is probably not causing harm. If the pointing is failing, there are loose stones or you can see cracks or gaps in the masonry beneath the ivy, the situation warrants proper attention to the wall as well as consideration of the ivy.

How to Remove Ivy From a Wall Safely

If you decide to remove ivy from a house wall, the method matters. Do not pull ivy off a wall while it is still alive. Living ivy adheres firmly to the masonry and pulling it off strips mortar and can pull away loose stones or pointing along with the stems. The correct method is to cut all the stems at the base and leave the ivy to die in place for a full growing season. Once dead and dry, the stems and adhesive roots loosen their grip on the masonry significantly and can be removed with much less risk of damage to the wall beneath.

After removal, the wall should be inspected and any areas of failed pointing should be repointed before the surface is exposed to a Cumbrian winter. The exposed wall face, if it has been covered for many years, may also show areas of algal or lichen growth that can be treated with an appropriate biocide wash.

On older stone properties of the type common across Grange-over-Sands and the Cartmel Peninsula, we would recommend having the repointing done with a lime mortar appropriate to the age and type of the stone, rather than a cement mortar, which is too hard and can cause damage to older soft stone.

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