Yes it's a roof coating.
It gives some perfect results about covering small gaps. It prevents from EVERY paint crack since the paint coat is traped between this and the flexible varnish. I can fold a piece at 180° and step on it, it won't show the smallest single paint crack neigher during or after.
Making this roof stuff completely flat and smooth with a brush (a soft brush) is quite easy, but requiers multiple coats and a lot of patience. I can do it on some small parts as a test, but never had the patience needed to make it with care on an entire suit...