Most home insurance policies do not include damage such as deterioration of a building or property caused by mould (microscopic fungi that can also be harmful to people or animals).
To prevent mould from forming in your home, air it out regularly! If, despite everything, traces of mould appear, scrub them with a bleach and water solution.
If you have a recurring leak in your roof or foundation, don’t let the problem drag on. Prevent mould by attacking it at the source.