Gutter types and downspouts
Seamless aluminum and seamless steel: these gutters are pre-painted, and a wide selection of colors are available.
Galvanized, bonderized steel: these gutters are not painted.
Copper: 16 oz and 20 oz.
Most homeowners today are installing seamless aluminum gutters because there are lower in cost, do not rust, and are pre-painted. Aluminum is softer than steel and may be dented from ladders more easily.
Seamless pre-painted steel gutters are an alternative to aluminum; they are heavier and resist denting more than aluminum.
Note “seamless” gutters do have seams at any inside or outside corner on a house. Seamless gutters cannot be soldered at their seams, so they are sealed with rivets and gutter caulk. It is critical that the gutter flaps (the joining area at the gutter seam) are solidly riveted together and heavily sealed with gutter caulking to prevent leaks.