Moss, lichen and damp tiles
A little moss on a roof is common, and it is not an emergency. The trouble starts when it builds up thickly. Moss holds moisture against the tile, lifts edges and can block the channels between interlocking tiles. In frost, trapped water expands and flakes the surface.
Removing moss needs a careful hand. Hard pressure washing can strip tile surfaces and push water under the laps, so gentler cleaning and a treatment are usually better. Where the cause is lack of light, trimming overhanging branches helps more than any treatment. We check the tile surface and the laps when we visit, and say what we think is worth doing.





