The semicircular and trapezoidal shaped gutters offer least resistance and result in optimum flow. Their wider mouth reduces wastage of water by splashing. Semi circular gutters are usually preferred since other shapes are not easily available and this one can be easily created by slicing a PVC cylindrical pipe in half. Rectangular, trapezoidal and V shape gutters are usually made from Zinc sheets.
Common material for downtake pipes are ultra-violet treated Poly Vinyl Chloride (PVC), Galvanized Iron (GI), Cast Iron and asbestos cement. Downtake pipes will be present in most buildings, leading rainwater to the ground. Older constructions would have asbestos cement pipes but more recent ones would have PVC, and in a few cases GI downtake pipes. PVC pipes are preferred since they are
- cost effective
- do not rust
- are easy to procure, install and repair and
- allow for increased flow rates because they are smoother than their metal counterparts