On 2006-12-06, Thomas Prufer wrote:

Ack. Felt's not all that great, as UV breaks down the bitumen eventually.

Neighbor tossed a thick layer of sand on his ancient felt roof when he painted
his with bituminous paint. It has extended the life considerably -- the layer of
sand seems to protect the paint. His roof is fairly steep, though, I'd worry
that stuff would stick to the sand layer if it were flattish -- though moss
should protect form UV as well?

This one's not steep at all, although there's nothing growing on it
yet (a few years after installation).