In the picture a flat roof insulation underneath.
Professional Waterproofing Window closing Frosted glass.
Professional performance of connecting Bituminous sheets.
In this picture we can see a flat roof with tar sheets in Mevasseret Zion. Bubble sheets indicate that there is water inside, because the work was performed in an unprofessional manner.
the tar is placed up to the parapet, so that wont drop over time. Before that, the tar was placed at floor level only