Should ivy be removed from masonry walls? What is the best way to remove it?
For an answer you have to weigh the advantages and disadvantages of ivy. Ivy can add to the beauty of masonry walls and give them some protection. It reduces temperature fluctuations by keeping the walls cooler in the summer. And the leaves shed rainwater, preventing large amounts of water from reaching the masonry. In some cases, though, ivy can lead to moisture penetration problems or masonry deterioration. Ivy shoots can enter voids in mortar joints. Over time they can break up and dislodge mortar and masonry units. Ivy also can conduct moisture into walls and hold moisture against and within walls. This can contribute to efflorescence or moisture-related deterioration. Whether or not ivy will cause significant deterioration depends on the quality of the materials and workmanship of the masonry walls. According to the Brick Institute of America (BIA), in a well-constructed wall made of quality materials, deterioration due to ivy may reduce the life of the wall by 10% at most (Engineering and Research Digest, May 1980). Durability is not the only consideration, though. Ivy can provide homes for insects, birds, and other animals, which may then find ways to enter the building. Removing the ivy also may leave a defaced masonry wall. Depending on how deeply the shoots have penetrated the masonry, satisfactory removal of the ivy may be impossible. To evaluate the appearance of masonry after the ivy is removed, BIA recommends removing ivy from an inconspicuous area before removing it from the entire building. If you decide to remove ivy, BIA recommends the following procedure. First, cut the ivy carefully away from the walls. Pulling the ivy from walls may damage the walls. Let the remaining ivy shoots die and dry out for 2 to 3 weeks. (Wait longer than 3 weeks and the shoots may rot and oxidize, making them difficult to remove.) Remove the dried shoots with a stiff brush and water. Add a small amount of laundry detergent to water to aid removal. If detergent is used, rinse the wall thoroughly with clean water afterward.