Building Science


There’s more to improving a home’s energy performance than simply adding insulation, though it’s an excellent starting point! Every home is a system made up of separate components—the building envelope, mechanical systems and occupants—whose interactions affect how much moisture the home generates and how well it manages that moisture. CertainTeed offers innovative products that work with our insulation to
provide improved protection against moisture’s potentially damaging effects.

It’s unavoidable—but manageable

A family of four can produce two to three gallons of water vapor every day simply by bathing, laundering, cooking—even breathing. During the heating season, this vapor is drawn from the home’s warm interior to the cooler exterior. If its movement into attics and exterior wall cavities is not minimized by a vapor retarder, condensation occurs when the vapor contacts a cold surface. Continued exposure to such damp conditions can compromise insulation performance, damage wood framing and cause mold and mildew to grow.

Vapor Retarders

A vapor retarder is any material that limits or restricts the transmission of water vapor. CertainTeed fiberglass insulation is available with either kraft, smart, foil or flame resistant facings that function as vapor retarders.

Unfaced insulation requires a separate vapor retarder, typically polyethylene film. CertainTeed MemBrain™ Continuous Air Barrier & Smart Vapor Retarder is an innovative option that actually changes its permeability to water vapor depending on ambient humidity.

Mold on wall and young girl with inhaler.

Interesting Mold Facts

There are thousands of known species of mold, but they all require the same four things to live:

  1. Food source—typically starch
    or sugar
  2. Temperature—cozy 41° F to 140° F
  3. Oxygen
  4. Water

Once mold growth has started, each mold colony (mycelium) produces
millions of microscopic spores within a few days

What homeowners think of mold:*

  • Health Risk— 65% listed as #1 concern
  • Expense of Repair— 31% listed as #2 concern
  • Structural Damage— 27% listed as #3 concern

84% would not buy a home with a history of mold, and 48% said they would sue a builder, previous owner or landlord if they found mold in their walls.

Simple steps can be taken to prevent mold and subsequent effects to health
and home, but once mold starts to grow, remediation is a lengthy and costly process.

*Conducted by National Opinion Research for CertainTeed Corp.