Chrisbo, The rubber roof is a one piece membrane. When we went through the factory, in Warsaw, IN, They told us to clean the roof with liquid Ivory soap and warm water, once a year, after allowing the roof to dry, remove the caulking and re-caulk with rubber roof calk. This is a special caulk for RV ruber roofs, USE ONLY THIS SPECIAL CAULK.
The job is not complacated and the old caulk is easy to remove. The first time (when the unit was two years old) I saw a few spots that were starting to seperate from the ruber roof, and could have caused a leak.
We have had our 211 in Alaska twice, Florida three times and all of the western and midwestern states. With 45000 and not so much as a spark plug replaced we are very happy with our B+.