Damp is very common in UK homes and can have all kinds of affects, including causing mould on walls and furniture or making timber window frames rot. Damp also encourages the growth of mould and mites which can be bad for your health. The mould fungi have been identified as the source of many health problems, including infections, asthma, allergies and sinusitis. Moulds produce allergens, irritants, and in some cases, toxins that may cause allergic reactions in humans. While some damp is caused by a problem with the building itself, many cases are caused by condensation. Knowing the cause of the problem will help determine what needs to be done and by whom.