 pam shield it's a synthetic underlayment yeah and it's plastic and they use that instead of felt paper yeah right it's synthetic and it's actually an upgrade to standard 15 pound felt paper and it's actually better than using standard felt paper under a roof the reason that your roof is leaking now is probably not because of the tam shield it's probably because of something that went wrong with the repair but i don't think it would have been the underlayment because that's actually pretty good stuff