Moss in itself will not cause any great harm to a concrete roof tile in the short term, but certainly can in the,longer term.
One of the problems with moss is that it holds incredible amount of water (up to 30 times it’s own weight in some cases) and a roof covered in moss can put a huge strain on the structure of the roof when wet (which by it’s nature moss needs to be), and because moss retains water, when it freezes and thaws during the winter months, it can start to break up the tile surface, which obviously isn’t good.
Moss also grows under the roof tile and can actually lift the tile clear of the roof, this creates gaps in the roof surface and allows wind and rain to gain access to the felt, timbers and roof void, which also isn’t good.
Another often overlooked fact is that moss harbours many and varied species of insect life, which is what attracts the birds to it, the birds also defecate randomly all over the roof while attacking the insects living in the moss, not good for either appearance or the tiles themselves.
And yet another problem caused by having birds feeding on your roof is that they remove the bush part of the moss to get the insects, this moss then rolls down the roof, and either ends up in your gutters or on the ground around the house, which is not only messy, but causes blocked gutters, blocked downpipes, fascia rot, as well as moss growth on the ground around the property.
So is it a good idea to remove moss from your roof….yes!
Posted in: Roof cleaning
