When roofs leak and people get wet, there is generally an immediate response to correct the condition.
But what happens when water gets into a wall assembly and never surfaces to the inside room? What happens when water enters the outside of the wall but does not travel all the way through the wall to the inside? As waterproofing specialists for over 50 years and counting, we see the devastation that these unseen leaks cause. The wetting and drying of wall materials is sometimes called a slow-fire. It can be as damaging as a real fire leading to rotting of wood or rusting of steel supports. Often, we must rebuild walls and perform major structural repairs as a result of minor leaks that are either not observed or neglected. These costs are always significantly higher than simply waterproofing the area and preventing water intrusion.
And if structural damage does not occur, water in a wall assembly will almost always lead to the proliferation of mold. Mold of course can spread in the home unseen and lead to health issues if not corrected. That is why it is critical to pro-actively inspect for water intrusion conditions that might be entering a wall.
The moral of the story is to waterproof your home or building before the water is allowed to do damage.