Box

The Box gutter profile system is more suited to a large house with a high-pitched roof, small commercial buildings and conservatory box gutters, where a high flow capacity is required. It is designed to be soldered where the gutter lengths and corners join (and to insert box gutter outlets. These are patch outlets, so you cut out the hole for the spigot using a hole cutter of 75mm or 92mm diameter depending on the diameter of downpipe being fitted). Therefore, this system requires a slightly higher skill set.
Plus, the 120mm wide box guttering system's fascia brackets are far stronger (recommended spaced at 400mm intervals) to support a greater weight of water or snow load.
Soldered gutters must allow for thermal movement. Traditional high point movement joints can be used as can soldered expansion joints - either should be installed at a max distance of 8m.