The vinyl siding, brick, or other exterior cladding options for our homes certainly play an essential role in protecting our home from the wind, rain, and other external elements. However, hidden beneath the cladding, house wrap also contributes to keeping our home dry, comfortably cool or warm (depending on the season), and otherwise protected.

So why exactly do homes need to be wrapped up in a synthetic barrier? First and foremost, No matter what type of exterior cladding option you have, cracks and fissures can occur over time. During times of driving rain or when your roof gutters get clogged and end up leaking, water can penetrate your exterior siding. This water penetration can cause significant damage to your interior wall assembly.

Excess amounts of water and moisture can cause mold to grow on your plywood or drywall or even weaken the structural stability of your house frame. If water gets into your inner-wall insulation, it can cause compaction, thus lowering the R-value of your home and driving up your energy bills.

In the past, contractors tended to prefer asphalt-treated paper or asphalt-saturated felt. These options were heavier and harder to apply to the building exterior before they installed the external cladding. The asphalt-treated paper also risked lowering your indoor air quality. It could increase the volatile organic compounds (VOCs) in your home, especially if the building envelope were not air-tight. According to the Occupational Safety and Health Administration (OSHA), exposure to asphalt fumes includes headaches, skin rash, sensitization, fatigue, reduced appetite, throat, eye irritation, cough, and skin cancer. These side effects are not exactly what you look for in a healthy home.

Today, most builders prefer the more lightweight synthetic house wrap options. This type of house wrap is easier to apply and broader than traditional asphalt paper.