Moisture Conditions in Walls and Ceilings of a Simulated Older Home During Winter.

Abstract : Many homes, built without insulation and consequently without vapor barriers, have had insulation added later. In many such homes no moisture problem has become apparent; in others paint has peeled, etc. Even where there is no external evidence, moisture buildup in wall and ceiling insulation can reduce its effectiveness. To obtain information on moisture in insulated walls and ceilings which lack vapor barriers, a small exposure unit was instrumented. Test data showed that insulation added to walls of an older home subject to the climate at Madison, Wis., may not cause visible moisture problems where mechanical humidification is not used. However, where a relative humidity of 35% is maintained in the house, condensation in the walls is likely without remedial measures. Increasing depth of ceiling insulation resulted in a slight increase of moisture in the insulation, but good ventilation kept moisture at acceptable levels.