insulation, vapor barriers and moisture

We need humidity in the air we breathe, but too much moisture can damage the building materials and be a source of health problems. Uncontrolled moisture can lead to mold growth and other problems.

Keeping Moisture away

VAPOR VS. RADIANT BARRIERS
Vapor Barriers are different from Radiant Barriers. Radiant Barriers are used to prevent the sun's heat and are mainly applied in exterior surfaces, while Vapor Barriers are used to protect interior living spaces from moisture.

When moist air comes into contact with cold surfaces, part of it condenses, and when it happens in the attic or inside a wall, away of our seeing, that's a source of problems.

A good painting and other siding elements are a first line of defense for preventing moisture. But also is a proper insulation - including the insulation of interior walls or basements and attics.

The Right insulation materials

Choose water-resistant insulation materials. There are several: polythene sheets, foil backed plasterboards, polystyrene (see: Spray-on foam insulation), reflective foils... Several high-efficient foams have water-resistant membranes...

Vapor barriers

Vapor barriers are an intrinsic part of many insulation products. Floors, framed walls or roofs with vapor barriers on the warm, moist side of the insulation, will be much more protected from water damages.

Floor slabs contacting the ground should benefit from a continuous vapor barrier, to prevent moisture to seep in.

installing a vapor barrier

Tape or glue the vapor barriers joints. Ensure they form a continuous sheet, undamaged and tightly secured.

Use vapor barriers to protect materials from condensation in places with low ventilation or on the underside of metal roofs. Vapor barriers are also especially important in lockers, showers and other areas of the house where the humidity levels are typically high.

Other Means of controlling moisture

Areas like windows, doors or roof flashing are especially important to fight moisture. Sealing them is crucial.

Drainage is also crucial: sloped roofs, sloped intake plenum, ground slope around the building, sufficient overhang in exterior entries, well cleared and opened gutters and downspouts should be properly addressed. See: Drainage.

Adequate ventilation of spaces where moisture can build up is also crucial. Pay attention to building codes demands for crawl spaces, attics and vaulted ceilings.

But, be careful... Ventilation can also be a cause of moisture and condensation in our homes, in some climates. Excessive ventilation in humid (cold or tropical climates) is an easy cause of moisture.