The top floor of a building may have the highest price tag, but it also has the highest risk of leaking through a failed roof system.
The most common causes of leaks in a penthouse suite (outside of plumbing) are;
Pipe Penetrations in the ceiling
Conduits through the slab
Failed waterproofing in mechanical rooms, overhangs, or balconies
Cracks in the concrete ceiling or walls
Roofing projects should be budgeted for accordingly. When the time does come for replacement, the work will be scheduled during dry weather. So, if a leak occurs in the wet season you need someone who can act fast and perform work in any weather. The injection process is sometimes needed urgently, to quickly and efficiently seal active leaks in any weather.