Plants don’t grow on dry, solid concrete or tightly sealed joints. If you see little tufts of grass, weeds or moss sprouting from cracks in the roof surface, joints, or expansion gaps, it means moisture is sitting there long enough to support growth.
Roots from these plants, even tiny ones, can wedge into small gaps and slowly force them wider as they grow. That opens more pathways for water to enter, worsening leaks and damaging the structure. Over time, what started as a hairline crack becomes a proper gap.
So while a bit of green on the roof might look cute at first glance, it’s actually a warning sign. Removing the plants and properly sealing and repairing the area is important, not just for looks but for the health of the building.
