Moisture in homes is unavoidable, making moisture in wall cavities nearly inevitable - and dangerous if not properly addressed.  CertainTeed's MemBrain™ Continuous Air Barrier & Smart Vapor Retarder is the industry's most advanced technology to create a better performing home.

In "mixed-climate" parts of the country, where homes heat in the winter and cool in the summer, homes using traditional polyethylene vapor retarders may actually trap moisture in the cavity during the summer - raising the risk of costly moisture and mold issues, structural damage, health consequences and liability.

This patented, revolutionary solution can provide a continuous air barrier along with advanced moisture management in a single product, helping achieve Complete Comfort.  It's another reason why choosing CertainTeed means you're installing much more than trusted high-performance insulation products.You're installing confidence.

LOW Humidity

Remains tight in winter when humidity in the cavity is low to prevent moisture from entering.


HIGH Humidity

Increases permeability in summer to let moisture escape, helping to keep the wall dry.


  • Continuous indoor air barrier* creates a better performing building envelope.
  • Dynamic performance and permeance rating compared to traditional kraft insulation or polyethylene sheeting.
  • Senses and adapts permeance to varying humidity throughout the year to keep the cavity dry.
  • When installed with standard tape and sealing practices, creates an air barrier that has been tested under stringent performance guidelines.

*For more information view the full MemBrain Air Barrier Instructions.

Where to Use MemBrain

Vapor retarders are required by code in zones 4C and above. However, MemBrain is ideal for any area where the home cools in the summer and heats in the winter.

  • Ceilings
  • Crawlspaces
  • Basements
  • Bathrooms
  • Laundry Rooms
  • Kitchens
  • Exterior
  • Walls

CertainTeed’s MemBrain™ Continuous Air Barrier & Smart Vapor Retarder

CertainTeed’s MemBrain™ Continuous Air Barrier & Smart Vapor Retarder


MemBrain should be installed in all insulated walls and ceilings, including cathedral ceilings. For most areas, vapor retarders should be installed on the warm-in-the-winter side of the insulation (toward the interior). For some warm and humid areas, vapor retarders, if used, should be installed outside the heating or building envelope. MemBrain is not intended to be used as an exterior vapor retarder. Check local practice and/or building codes before installation.

Sustainability Information

CertainTeed insulation products improve building energy efficiency and reduce building energy consumption for the life of the structure. As a result, they help conserve nonrenewable energy sources, decrease dependence on foreign oil and lower greenhouse gas emissions. In addition, the recycled content of CertainTeed fiberglass insulation meets the EPA minimum Recovered Material Guideline for fiberglass products consisting of pre-consumer and post-consumer glass cullet.

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