There are few points to avoid water leakage issues on your ready terrace.
Firstly look for there’s no water stabbing on your terrace. The slope of terrace shall correctly be given i.e. towards outwards. If the slope is not rightly constructed, water will get accumulated in areas causing damage to flooring which leads to water leakage problems.
Also look for drainage hole for water to easily flow out.
Look for no crack formation on existing terrace.
To avoid water leakage problems home owners can get a waterproofing coating done on existing terrace.
If there’s any seepage issues due to cracks especially, it will damage the steel/metal structure of the building. Once water comes in contact with steel or metal, the metal will start corroding causing expansion that weakens the structure. This corrosion will result in concrete slab to fall down (very commonly said in Mumbai – गाबड़ा गिरता हैं ), thus damaging the building.
Home owners shall also look for the pipe that goes through the roof or parapet wall.