If you were to make a list of the most frequent complaints in newly completed projects in our region, leaks would be number one. Not number five. Not among the minor problems. Number one. Above finishes, above doors that don't close, above any other defect.
And the paradox is that it's not just a problem with old buildings. Projects delivered months ago are already leaking. Towers that were sold as premium have damp patches on ceilings and walls before the buyer has even finished unpacking.
The problem isn't the material. There are excellent waterproofing products available on the market—asphalt membranes, polyurethanes, cementitious systems, PVC sheets. The problem is the installation. And more specifically, the construction details that are ignored, simplified, or skipped to save time.
The critical points are always the same: the joints where the roof meets a vertical wall. The edges of drains. Penetrations of pipes, cables, and ducts. Changes in level. Inside corners. Parapets. Each of these points requires specific treatment—reinforcement, overlapping, sealing—that doesn't allow for improvisation. And each of these points is where shortcuts are taken.
Waterproofing applied to an unclean surface will not adhere. A membrane without sufficient overlap at the joints leaves an open path for water. A drain without perimeter reinforcement becomes the exact point of leakage. A vertical wall without a cove base allows water to seep in through the most vulnerable angle of the entire structure.
And the worst part: leaks don't appear immediately. They can take weeks or months to manifest—the time it takes for water to find its way through the slab, through the tiniest crack, until it appears as a stain on the ceiling of the apartment below. By then, the damage is already done. Repairing it involves demolishing finishes, identifying the point of entry—which is almost never directly above the stain—and redoing the work that should have been done right from the start.
The cost of properly waterproofing a roof or terrace represents between 2% and 4% of the total construction cost. The cost of repairing a leak after completion can be 10 or 15 times higher—not to mention the damage to the project's reputation and the frustration of the buyer who paid for something that's supposed to work.
If you're building: oversee the details, not just the overall application. If you're buying: ask what waterproofing system your roof has, who applied it, and how long the warranty is. If the answer is vague, you know where you're going to have problems.
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