MemBrain Protects

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...but also Breathes!

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The Smart Vapor Retarder

Clear Moisture Control. Only from CertainTeed.

Moisture is the bane of every builder and a hidden risk in every building. Lurking in the wall cavity, moisture creates ideal conditions for mold, mildew, rot and the respiratory health problems they can cause. Especially in regions with extreme seasonal fluctuations in climate and humidity, there’s no foolproof way to keep moisture from getting into a wall. But now there’s a revolutionary way to help get it out.

MemBrain was designed on an ingenious principle: If you can’t escape the possibility of moisture entering a wall, why not let the moisture in the wall escape? Made from an advanced material that changes its permeability with the ambient humidity condition, MemBrain acts like a traditional vapor retarder to protect wall cavities, but also allows closed building envelope systems to dramatically increase their drying potential with seasonal climatic changes.

Designed to be applied over unfaced fiber glass insulation, loose-fill applications and spray foam, MemBrain looks similar to typical polyethylene sheeting, but is actually a polyamide-based material that gives MemBrain its unique ability to adapt its permeability depending on the climatic conditions. With a high resistance to water vapor in winter or low humidity, MemBrain behaves like a moisture vapor retarder such as poly sheeting. When the relative humidity increases, as in the summer season, its water vapor permeability increases dramatically. This allows water vapor to escape the wall cavity easily.

Vapor retarders have been used for decades to protect the wooden parts in a roof or wall from moisture damage by minimizing the diffusion of moisture in areas where it can create problems. But these vapor retarders have a fixed permeability that can’t adapt to changing conditions. The patented MemBrain technology was first introduced in Europe over ten years ago and is steadily becoming the preferred vapor retarder among European specifiers.

Using MemBrain will reduce your risk/liability due to moisture problems. Though it is a high-quality, premium product, MemBrain will only add about $300-$500 to the total of a new home*. So using MemBrain costs just a little more, but is always a smart investment.
* Based on an approximate exterior wall space for an average 2,400 sq. ft. home.

These insulation products may qualify for rebates and other incentives. For more information, visit for your area’s specific offers. 

CertainTeed cares about the environment and Building Responsibly™, and for more than 100 years has maintained a commitment to provide sustainable, innovative solutions that improve energy efficiency and comfort. From production to product, CertainTeed's focus has been on minimizing its impact on the environment by reducing energy consumption, conserving renewable resources and lowering greenhouse gas emissions. And with our Sustainable Insulation® fiber glass products, the mission continues. Visit for more information or watch our YouTube video.

Applicable Standards and Codes:
  • ICC
  • CCMC 13278-R
  • CAN/ULC-S102

Material Standards:
  • ASTM C 665 Section 7.4, Water-Vapor Permeance
  • ASTM E 96

Fire Resistance:
  • ASTM E 84 Surface burning characteristics: Max. Flame Spread Index: 20; Max. Smoke Developed Index: 55

Water Vapor Permeance
  • ≤1.0 perm (57ng/Pa•s•m2) (ASTM E 96, Desiccant method)
  • > 10 perms (572ng/Pa•s•m2) (ASTM E 96, Water method)
Fungi Resistance:
  • No growth (ASTM C 1338)


  • ASTM C 665 - No unusual aspect of corrosion such as pitting, cracking and adhesive cure inhibition

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.
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 fiber glass insulation meets the EPA Recovered Material Guideline for fiber glass products, 20-25% consisting of pre-consumer and post-consumer glass cullet.