I don’t do commercial inspection but a friend asked me if it was normal to have insulation on top of the rubber membrane on a flat roof. It was built 20yrs. ago and today the insulation is so soaked that you can’t lift it as it’s too heavy. Personally, I’ve never seen or heard of a roof done that way. Sorry no pictures, has anyone heard or seen this.
Inverted roof system.
Water proof membrane first, insulation then applied on membrane, a separation barrier over the insulation and then finally aggregate or other form of ballast to cover that.
When the separation barrier deteriorates or is torn the water gets down and soaks the insulation. Some installations may not even have it since it is only recommended.
According to some roofers and manufacturers this is not a problem unless the water proof membrane is exposed to the elements.