After a time, your felt shingles will start to age - a natural process that sees a change in colour and often take on a green tinge of either moss, algae or both. If, like me, you want to keep your garden building looking as good as possible it will be necessary to spend a bit of time cleaning the felt shingles.
This process is probably only required once every four or five years, but think of it as time well spent. Not only will it get the shingles looking far tidier and fresh, it will also ensure longer life. A build up of moss will eventually cause the grit and underlying fibres of the felt to deteriorate as the root system buries itself into the textile. Long term and the felt will give up and in extreme cases fall apart.
So, what are the options for cleaning the felt shingles ?
In all cases, if working on the roof pay attention to your safety. The pitch of the roof and algae can make this a dangerous environment to operate. Wear sensible footwear and never take risks by over stretching. Always maintain good balance and two firm points of contact with the roof.
Here is a recently cleaned roof by pressure washer - the next job will be to re-apply the wood preserve.