To prevent it damaging the walls drenching persons standing below or entering the building and to direct the water to a suitable disposal site where.
Rain collection zinc coated roof.
Unpainted zinc aluminium coated or galvanised steel.
Small mammals birds and insects deposit fecal matter.
Galvanized metal roofing especially is recommended for rainwater harvesting because the panels will be coated with a later of zinc which seals the metal panels prevents rusting and lowers the levels of iron in your water.
It is necessary to prevent water dripping or flowing off roofs in an uncontrolled manner for several reasons.
A rain gutter eavestrough eaves shoot or surface water collection channel is a component of a water discharge system for a building.
Rainwater can absorb zinc copper and aluminum from metal roofs as well as chemicals used for weatherizing and waterproofing asphalt shingles.
If rainwater is being harvested for human consumption roofing spouting downpipes and pipework materials must comply with as nzs 4020 2018 testing of products for use in contact with drinking water.
Aluminum copper and zinc roofs do not need to be coated.
Galvanised metal roofs have zinc coating the material therefore is a mix of both zinc and iron that prevents the material from rusting.
The american rainwater catchment systems association arcsa advises that standing seam roofs powder coated or enameled galvalume zinc aluminum alloy with non toxic baked or enamel finish are appropriate for potable use with non toxic finishes and appropriate components tanks and post tank treatment.
Like many other metals zinc is fully recyclable.
Plus it will reflect solar radiant heat as most metals do to some degree which prevents the unwanted transfer of heat from the roofing material into the attic space.
Small amounts of these chemicals end up in your rain barrel every time it rains.
Rust introduces high levels of iron into water collected.
Asphalt shingles contain zinc hydrocarbons and other chemicals as well as moss and algae preventatives.