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Variable moisture barrier

Miofol Active

Miofol® Active is a moisture-variable membrane, which is made from non-woven polypropylene and a polyethylene-copolymer film.

1,50 x 30 m Article no. 8608415030


Miofol® Active is a moisture-variable membrane, which is made from non-woven polypropylene and a polyethylene-copolymer film. The membrane serves a double function: In the winter, when it is warmer inside than it is outside, vapor flows from indoors to outdoors. Relative humidity is also low in the winter, which means the polyethylene-copolymer film will be closed and serve as a moisture barrier. As a result, almost no vapor can enter the construction during the winter. In the summer, vapor primarily flows from outdoors to indoors, and relative humidity is high both indoors and outdoors, which means the polyethylene-copolymer film will be open. Because the membrane is permeable, moisture can leave the construction and flow indoors.


Miofol® Active is used in wall and roof constructions. Miofol® Active is used on the warm side of constructions in combination with mineral wool like rock wool or glass wool. This membrane works particularly effectively in situations where a vapour control or vapour barrier layer has been placed on the outside of the construction (like on flat roofs) because moisture cannot escape via the cold side. Miofol® Active cannot be used in moist rooms like bathrooms.


Miofol® Active should be applied to the warm side of roof and facade constructions. Use staples to attach Miofol® Active to the underlying construction, directly against the mineral wool. To ensure effective moisture-regulation, place an air cavity between the membrane and the wall finish. Keep an extra 100 mm at all horizontal and vertical overlaps. To ensure effective moisture inhibition, we recommend using VAST-R® Non-woven tape to tape over staples, joints and overlaps. Use VAST-R® Butyl tape or Tyvek® FlexWrap tape to make openings and joints wind- and watertight.


Helps to create a healthy indoor climate

Allows insulation to continue functioning effectively

Lower energy costs


Allows construction to dry faster

Intelligent self-regulating vapor barrier

Variable SD rating


Weight 85 gr /m²

Fire class E

Water tightness W1

Water vapour transmission 2-96 g / m² / day

Tensile strength machine direction 110N / 50 mm

Tensile strength cross direction 80N / 50 mm

Elongation machine direction 40%

Elongation cross direction 35%

Tear resistance machine direction 60N

Tear resistance cross direction 60N

Temprature resistance -40°C/80°C

Construction phase 4 months

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