Hello everyone. We recently had the roof waterproofing redone on the apartment building where we live. There are 6 apartments on our section of the building. Five of them were waterproofed, while the sixth apartment, which is located on the corner, was left untreated.
The layout is as follows: 3 apartments on the left and 3 on the right. The apartment that was not waterproofed is on the right-hand side.
We are still experiencing water leaks. They are affecting 3 of the 5 apartments that were waterproofed, as well as the stairwell.
The new waterproofing was installed over an existing system. The building had already been waterproofed with 3 layers of bituminous membrane and sloped EPS insulation. We simply added another top waterproofing layer over the existing system.
I spoke to the contractor, and he explained that because the sixth apartment was not waterproofed, water is getting in through that area, passing beneath the EPS insulation, and reaching the concrete roof slab. According to him, the slab was poured without a proper slope to drain the water, so the water spreads wherever it can and eventually reaches the 3 affected apartments.
I'd like to hear your opinions. What should we do in this situation?
The recently installed waterproofing looks flawless. I went up to the roof with the contractor, and he inspected every seam. Everything is properly bonded and installed according to the relevant standards.