Insulation, Vapor Barrier and Ventilation Working Together to Achieve the Best Result
by Mark Row
There's more to home insulation than meets the eye
Proper building insulation is much more complex then simply choosing and installing a certain insulation material. Heat transfer is the problem that is tackled by insulation application, but what about moisture? That’s where vapor barrier and good ventilation come in. In order to stop the moisture to pass through the wall, ceiling and floor, vapor barrier must be created on external and internal surfaces, especially in bathrooms, kitchens, lofts and roofs, and ventilation will stop condensation and mold growth in your home.
Lack of insulation, vapor barrier and proper ventilation created moisture condensation and mildew growth.
How moisture enters the buildings? Large amounts of moisture come directly from precipitation or humidity and enter the buildings through a weak point in the facade. This can occur in the improperly sealed joints around openings or between facade elements. Once it enters the wall, trapped moisture can cause damage to the property and endanger the health of the inhabitants. That’s why external walls must be designed to prevent excessive penetration of external moisture by adding a vapor barrier. But that’s not all, every day living inside the building also creates moisture that has the exactly same effects as the external one. This calls for the vapor barrier to be set on the inner side of external walls and on all partition walls, ceilings, floors, lofts and roof. Humidity and water from the soil can potentially threaten the foundations of the building, especially if the underground construction has cracks. To avoid this it is best to insulate the foundation immediately during construction.
Vapor barriers reduce the passing of moisture in the form of steam. It’s very important to install the vapor barrier properly or it won’t stop the moisture from penetrating the object. To create a vapor barrier you can use aluminum foil, polyethylene sheet, low permeable paint, insulation materials with vapor barrier facing, vaporshield panel from Knauf, depending on what surface you need to install it of course.
Loft is the most important part of a building where heat transfer and moisture present a major problem. Vent openings play a crucial role at stopping moisture from condensing and enhancing the effectiveness of insulation and vapor barriers. In other parts of the house, like bathrooms and kitchens, dehumidifiers and exhaust fans can be installed to remove the excess moisture from the area.
Mildew formation in the insulated loft as a result of the lack of vapor barrier and ventilation.
Example of a properly insulated loft with a vapor barrier and ventilation in place.
Combining insulation, vapor barrier and ventilation will ensure your home will be energy efficient, structurally sound and safe for its inhabitants.
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