What is the white moss on Eastern white cedar shingles?
The white moss we sometimes see on green cedar shingles is caused by the cedar moisture content. It is not mold and mildew. This reaction is a possible occurrence on white cedar shingles kept tight in a bundle after a few weeks, especially during summer months, and is not related to any specific treatment to the logs. This white moss will wash away with rain and wind. There is no need to clean these shingles.
