Moulds are found everywhere inside and outside, and can grow on almost any substance when moisture is present. Moulds reproduce by spores, which can be carried by air currents and when these spores land on a moist surface that is suitable for life, they begin to grow. Mould is normally found indoors at levels that do not affect most healthy individuals.
Because common building materials are capable of sustaining mould growth, and mould spores are ubiquitous, mould growth in an indoor environment is typically related to water or moisture indoors. Mould growth may also be caused by incomplete drying of flooring materials such as concrete, flooding, leaky roofs, building maintenance problems, or indoor plumbing problems can lead to mould growth inside your home or business.
For significant mould growth to occur, there must be a source of water (which could be invisible humidity), a source of food, and a substrate capable of sustaining growth. Common building materials, such as plywood, drywall, furring strips, carpets, and carpet padding are food for moulds. In carpet, invisible dust and cellulose are the food sources. After a single incident of water damage occurs in a building, moulds grow inside walls and then become dormant until a subsequent incident of high humidity; this illustrates how mould can appear to be a sudden problem, long after a previous flood or water incident that did not produce such a problem.
Both infants & the elderly in particular, may develop respiratory symptoms as a result of exposure to mould & mould exposures cause a variety of health issues depending on the person such as; throat irritation, nasal stuffiness, eye irritation, cough and wheezing, as well as skin irritation in some cases.
Please bear in mind that although in most cases water damage / flood damage will be covered by household insurance, however, if mould is allowed to develop that cleanup and removal of mould is not covered in most cases.