Now follows the most tedious part of the work, as the many small adhesive roots and bark residues must be removed. Before you begin, you should first thoroughly soak the facade with water so that the little roots swell and become soft. To do this, spray the wall repeatedly with the garden hose over several hours or set up a lawn sprinkler that keeps it continuously moist. Afterwards, remove the roots piece by piece with a scrub brush or a hand brush. It is important in both cases that the bristles are as hard as possible. Rinse the already scrubbed-off areas again to see if any adhesive root residues remain.
On plastered walls or from the joints of brick walls, the roots are easier to remove if you scrub the wall once briefly with diluted hydrochloric acid [Salzsäure] after soaking and let it act for a few minutes. The acid dissolves lime plaster and lime-containing wall paints and ensures that the ivy roots no longer adhere quite so firmly. After acid treatment and exposure time, the acid must first be rinsed off with tap water before you use the brush again. On very smooth walls or facades made of concrete, a spatula with a straight, sharp metal edge is also a good tool to scrape off the roots. A high-pressure cleaner with a sharp flat jet sometimes also does a good job.