A wall can hide plenty of surprises. There is always mould in the air. It is therefore normal to find the same types of mould in houses as those found outside, at comparable or lower concentrations. Yet, according to the provincial health watchdog, l’Institut national de Santé publique du Québec (INSPQ)1 a third of Canadian houses do not meet this criterion. In this group, a third of the houses are contaminated at levels ranging from weak to very high.
In order to grow, mould needs moisture.
That’s why, as much as possible, it is important to control the level of moisture in a house, to maintain humidity levels of around 30%2 during winter, and never above 55% in the summer. It's also important to ensure there is no water leakage, in which case, risk of contamination is much higher.
- INSTITUT NATIONAL DE LA SANTÉ PUBLIQUE DU CANADA, «Rapport scientifique: Les risques à la santé associés à la présence de moisissures en milieu intérieur», Québec, Novembre 2002. p.12
- Ibid., p. 9