What makes an eco-friendly building material?

1. Manufacture
The key points are whether the material came from a sustainable source, such as timber from a sustainably managed plantation, and how much energy was used to make it (its “embodied energy"). For instance, steel needs a lot of energy to manufacture while mud brick need none. Transport fuel is part of a product’s embodied energy so for remote locations, lightweight materials may be more eco-friendly.
2. Insulation
Materials with good insulation properties are more eco-friendly because less energy will be needed to heat and cool your home.
3. Longevity
The longer-lasting it is, the better for the environment – and for you
4. Disposal and recycling
Is the material easy to dispose of in an environmentally friendly way? Better still, can it be recycled?