In this video, a Southern California roofer discusses gutter installation. Many homes in Southern California do not have gutters, because it rains very infrequently, but gutters are common in places that get a lot of rain. Gutters are important because they prevent water from accumulating at and undermining the foundations of a house.
Without a gutter, rainfall can soak and undermine the earth near the house's foundation, causing cracks to appear and eventually making the foundation crumble. Yet the gutter system needs to be well-designed to work. The best gutters are seamless gutters made of nylon or aluminum. Unlike steel, neither of these materials will rust, and the seamless design means that water can't leak out. If using seamed gutter segments, avoid the joiners that come with them and put the gutters together overlapped with the overlapping inner segment to the downstream side of the gutter.
When designing the downspout, the gutter should decline just enough to channel the water to the spout, about ½ inch of rise to 6 feet of run. This can be facilitated by using a nail and chalk line.
Gutter design can save you thousands in home maintenance. A well-protected home is worth the cost..