A method for monitoring the load which is exerted on a roof includes the following steps: providing a roof with an external surface on which a load can be exerted by, for example, a layer of water or snow, providing a sensor for detecting a phenomenon related to the load which is exerted on the roof, monitoring the phenomenon with the sensor, storing at least one predetermined value for the phenomenon, emitting a signal when the value for the phenomenon detected by the sensor exceeds a predetermined value.