Delores writes from Waldron, Saskatchewan: "We have a problem with condensation on the ceilings along the north wall on each spot where there is a floor joist. This occurs when it is very cold like around 0 F. The attic has blown insulation and pink batts overtop. Other walls are OK. What can we do to stop the problem?"

Answer: Condensation of moisture in the indoor air will occur where warm air meets a cold surface. Although I do not have information on the exterior cladding or age of construction, it seems as if there is no air retarder continuity at the floor joist level. A weather barrier such as a housewrap needs to be wrapped at the joist level and connected to the indoor air/vapor retarder of the attic to insure an effective barrier against wind-driven cold air. In winter, the cold air will penetrate into the house walls and will cause condensation at leakage points, i.e. floor joists. The attached document will show you the area that probably needs to be addressed.