Guttering. Not necessarily a subject that you would think would be fraught with eco impact decisions, however there are an array of guttering materials available, and whilst some may have very high embodied energy, they may also contain a lot of recycled content.
Aluminium is recyclable, durable, lightweight, and products can/should contain a high level of recycled content.
On the down side, aluminium has a notoriously high embodied energy, due to the amount needed to extract it from bauxite. However, if it’s from Norway then this energy will be derived from completely renewable sources.
Cast iron and steel are recyclable, durable, and products are likely to contain up to 75% recycled content.
However, iron extraction leads to landscape degradation, and high levels of waste are associated with iron production, which also uses a lot of energy. Iron needs regular painting so as not to rust, whereas galvanising steel is responsible for high levels of pollution including dioxins.
Copper is the guttering material of choice for much of Europe, because it is recyclable, durable, contains a high level or recycled material, is corrosion resistant, and is very pretty.
However it is also a scarce resource – supplies are likely to be exhausted within 60 years at best, 25 at worst – which is why it is also expensive.
PVC should be the ideal material – it is cheap, tough, lightweight, theoretically recyclable, corrosion resistant, and needs little if any maintenance.
However PVC is a petrochemical product with associated high emissions and embodied energy, and there are concerns over PVC manufacture and disposal. PVC also degrades under UV, and so actually PVC guttering only has a short life span.
GRP (Glass Reinforced Polyester – Fibreglass)
GRP shares many of the advantages of PVC, except that it is not easily recycled unless perhaps as an ingredient in cement production, wherein the resins act as fuel and the minerals go into the cement.
GRP dust is a carcinogen and VOCs are emitted during production.
Wood is a long forgotten and yet oldest form of guttering material – including bamboo. It is durable if maintained and has very little environmental impact.
Without maintenance, however, wooden guttering will not last long, but will rot, split and crack – it is also difficult to find these days!