The article deals with the recommendations how to eliminate ice dam formation on pitched roofs of the buildings with cold attics during heating period. The case of how to calculate required air change in cold attic rooms, where building structures which separate attics from rooms or utilities with high temperature (heat supply sources) are not insulated, is given in details. It is proved that natural ventilation system can ensure this condition only within short terms. It is necessary to both carry out works to ensure air change and insulate building envelopes, which separate cold attics from rooms with higher air temperature in order to satisfy all the requirements to eliminate reasons of ice dam formation on roofs.