UV-resistant membranes continue to be watertight even if they have been exposed to UV radiation for a long period of time. If buildings have an open facade or if roof tiles have not been placed properly, facade cladding or roof cladding will not be completely sealed and regular membranes will become less effective over time due to UV radiation. UV-resistant membranes have been tested for a very long time in climate chambers that feature UV lights, and are thus guaranteed to offer the right protection.