Humidity and Your Home’s Building Envelope

The term “building envelope” refers to the outermost structure of homes and buildings. It includes all floors and walls, as well as the roof that keep the elements from entering your home. The integrity of the envelope refers to how tightly it resists air infiltration, moisture and thermal transfer. All three aspects of its integrity affect the amount you pay to keep it comfortable.

Humidity and Your Home’s Building Envelope

Moisture affects all parts of the exterior structure. Water and air can enter through the smallest cracks and crevices and set the stage for mold growth and wood rot. Some moisture is unavoidable since many building materials breathe, like wood products, insulation and drywall. Wood, especially, has an affinity for moisture and will release and absorb it easily depending on the humidity.

When too much moisture builds inside the envelope, materials can deteriorate. Insulation in the attic and walls can rot and lose its ability to resist temperature change. Mold can grow on insulation, wood products and drywall and destroy the strength of these building components.

Any place that lets water into the envelope also lets air pass through, making it harder to keep your home comfortable. As a consequence, the HVAC system has to run longer and more often, driving up energy costs.

Moisture Management

How can a homeowner maintain the building envelope to ensure humidity doesn’t make a mess of things? For the exterior, do the following:

• Work with a licensed contractor to assure adequate attic ventilation.
• Verify that gutters are clear and drain away from the foundation.
• Avoid planting vegetation next to the foundation.
• Seal cracks in the foundation and exterior walls.
• Replace any damaged roofing materials.
• Have your HVAC contractor clear the drain pipe for your HVAC system during the annual maintenance visit.

For interior moisture management, try the following:

• Use a central dehumidifier if summer humidity levels remain over 50 percent, even with the air conditioner running.
• Use kitchen and bathroom exhaust fans to remove excess moisture, especially in the summer.
• Fix all plumbing leaks promptly.

Keeping moisture out of the building envelope ensures the health of your home’s structure and promotes comfort. Learn more about how to control indoor air quality or contact Bass Air Conditioning Company at 910-778-1536.