Adding downspouts and a drainage system to your home gutters is a great idea! A good set of gutters will make sure that rainwater runoff from your roof water runs smoothly and flows down safely from your roof. However, if you have ever looked at the underside of a leaf lying in a gutter or downpipes, then you may have noticed some very interesting material that sometimes forms at the base of a leaf. Gutters are composed of many different materials, but the main material that they are made from is typically some form of concrete or some other non-permeable material. Now what is a downspout?