Bat boxes are to be made of rough-sawn soft wood sourced from a sustainably managed forest. Do not paint the box or treat it with preservative as these can harm the bats. There must be a 15 to 20 mm entrance gap at the base of the box.
Bird boxes are to be made with wood sourced from a sustainably managed forest. If required, treat the outside of the box with a water-based preservative. The dimensions and design of the box will depend on the species of bird likely to use it.