Hello all;
Eastern Hemlock is colloquially considered rot resistant here in Maine but the scientists, and my observations, rate hemlock as "non-durable" such as here:
http://www.wood-database.com/lumber-identification/softwoods/eastern-hemlock/The above site also discusses hemlocks working properties, etc.
That said, hemlock is one of the primary woods used in 19th century frames in Maine, though the quality seems lower now than then.
Jim