The product takes the form of a textured, single-sided, self-adhesive copper strip. The textured finish extends the rainwater run-off period, thereby intensifying the anti-moss effect. Moss growth on clay and concrete roof tiles is thus checked, even where the ridge strip is retrofitted. The time needed for the product to take effect depends on rainfall duration and the amount of moss growth prior to installation. Due to their low quantity, the washed-out copper ions pose no threat to the environment. The rainwater can be harvested for use in the garden.