Material selection can minimise potential impacts in a number of ways. The most obvious is visual impact, but careful selection can also have an influence over maintenance costs, thermal and acoustic insulation, drainage etc. They can help to break up mass and create form. Appropriate colouring can also minimise potential impact by linking a building with its surroundings. The potential impact caused by noise can be reduced by the careful selection of materials and the sensible location of certain elements of machinery. Living roofs can make a significant contribution to sustainable drainage strategies for a site and can also lead to biodiversity gains, possibly replacing habitats lost as result of the introduction of the building.