We own a floating home in Brooklyn, NY. My husband recently added an addition and it has an almost flat roof (.25 slope over 12 feet). He put down grace ice and water shield and was told he could cover that with liberty self stick base. we want to put liberty cap on top of that. Well, the grace went down ok and it is really stuck on there. the Liberty was put down next and looked good. the next day, there were blisters popping up. He thinks that the plastic-y coat on the grace I&ws is separating from the sticky layer and popping up under the liberty. We are not sure how to progress. He needs to get rid of the blisters before he can put the top layer down. Any ideas? Any help will be appreciated.