Interesting.
If you zoom in, you will notice that the moss isn’t growing on the slates which are too hot/dry to support growth.
The moss is only growing between the slates on the vertical joints. That implies that there is something below the top layer of slates that retains moisture – maybe accumulated debris or rotting wood.
Each year the moss is inhibited from spreading sideways by the hot/dry slates and can only grow upwards relying on the wicking effect of the previous year’s growth to keep them moist.
Keith,
Well spotted. You can’t see the roof very well from below and I hadn’t looked at the photos so closely, nor with such an expert’s eye. An intriguing explanation – and slightly worrying for the occupants I’d have thought.
Keith AVERY
14 May 2016 at 13:43
Interesting.
If you zoom in, you will notice that the moss isn’t growing on the slates which are too hot/dry to support growth.
The moss is only growing between the slates on the vertical joints. That implies that there is something below the top layer of slates that retains moisture – maybe accumulated debris or rotting wood.
Each year the moss is inhibited from spreading sideways by the hot/dry slates and can only grow upwards relying on the wicking effect of the previous year’s growth to keep them moist.
jackdeighton
15 May 2016 at 00:06
Keith,
Well spotted. You can’t see the roof very well from below and I hadn’t looked at the photos so closely, nor with such an expert’s eye. An intriguing explanation – and slightly worrying for the occupants I’d have thought.