Roofs have been a thing for millennia. Even in the Middle Age there are many building that survived throughout the centuries, drastic weather changes, wars etc. Many catholic cathedrals and churches are nowadays in good conditions and favorite attractions for millions of tourists every year. So, why were roof an important structure for these buildings? Aside beautiful paintings in the ceiling, the roof protected the interior of the buildings from water leakage and therefore corrosion. So, whenever you spot any leaking in your roof, repair it.