Water tanks, solar heaters, big AC outdoor units—these are heavy. If they sit directly on the roof surface without proper stands or spreader beams, their weight digs into the waterproofing layers. Over time, this can crack coatings, compress insulation and create low spots where water collects.
When you go up, look at how big items are supported. Are they on purpose-made blocks or frames that spread the load? Or are they just plonked straight on the slab with odd bricks here and there?
Proper supports respect both the structure and the waterproofing. Bad supports almost guarantee future leaks and expensive repairs. It’s a small visual check that tells you how thoughtfully the roof has been handled.