This new felted. apex roof as turned out to a total failure .in the specification all laps should have been sealed and bonded with mastic .they where not . I showed Steve Ruddy OSM Building contractors an example of the felt i wanted . but they used an inferior grade and used just nails and no mastic which has turned the roof into a colander. all instructions are written on the wrap around the roll of felt .to ignore the instructions was not a good idea . I have had no response from OSM