Water Barrier Breathable Membrane

The Water barrier breathable membrane manufactured by Xiashi Packing, a leading Chinese manufacturer, blocks liquid water while permitting water vapor escape, improving building airtightness and watertightness. Our waterproof and breathable membrane mitigates condensation, roof & wall mold, and damp insulation performance loss, serving as a core material for green low-energy buildings.

Working Principle

The water barrier breathable membrane utilizes the microporous screening principle to achieve both waterproofing and vapor transmission capabilities: the diameter of liquid water droplets is approximately 20 micrometers, whereas the diameter of water vapor molecules is only 0.0004 micrometers representing a vast size difference between the two. Through diffusion, water vapor can easily pass through the membrane's micropores and be discharged; in contrast, liquid rainwater or dew, due to surface tension, cannot penetrate these micropores, thereby enabling the unique "rainwater cannot enter, moisture can escape" breathing performance.

core advantage

House Dress water barrier breathable membrane features excellent waterproof performance and high water vapor permeability up to 1000g/m²·24h. It effectively blocks rain and dew from penetrating the building envelope and protects insulation materials from moisture damage, while allowing internal moisture inside walls and roofs to escape freely to prevent condensation, mold growth and component corrosion. With reliable air‑tight and wind‑proof performance, it can cut building HVAC energy consumption by up to 40%. Boasting high tensile strength,‑30℃ low temperature crack resistance and UV aging resistance, it adapts well to various working conditions including steel‑structure buildings, curtain walls and prefabricated constructions. It simplifies construction details and reduces overall project costs while improving indoor air quality. Compliant with Chinese building material standards and widely exported to Europe and America, it forms a complete building moisture management system when combined with sealing tapes and vapor barriers.

Technical Standard

Construction Precautions

Substrate & Environment：Ensure flat, dry substrate free of sharp objects. Avoid installation in rain, snow, fog or low temperature open‑air conditions to prevent membrane damage.

Laying & Overlap：Lay roofs from eave to ridge and walls from bottom upward. Maintain minimum 100 mm overlap and seal all joints with matched vapor permeable tape.

Fastening & Details：Fix with battens and washers. Apply extra sealing reinforcement for nail holes, doors/windows, pipe penetrations and corners to prevent air and water leakage.

UV Protection & Repair：Avoid long term UV exposure. Install outer cladding promptly. Keep away from welding sparks. Repair damages with matching membrane patch plus tape.

Correct System Matching：Place waterproof breathable membrane on the exterior side of insulation. Use only vapor permeable tape. Do not apply closed butyl tape or swap position with vapor barrier membrane.

FAQs

What is the difference between a water barrier breathable membrane and a vapor barrier membrane?

The water barrier breathable membrane offers high vapor transmission and is installed on the outer side of the insulation layer to allow moisture to escape; the vapor barrier film has low vapor transmission and is installed on the inner side to prevent moisture from penetrating the insulation layer. These two films are often used in combination.

Can the product be exported to Europe and the United States? Does it support sample requests?

Our products have been exported to Europe and the United States for many years; we support the shipment of test samples and custom specification requests, and can assist customers in arranging third-party testing.

Can low-temperature environments cause cracking or failure?

Standard products exhibit low-temperature bending performance without cracking even at –30°C, making them suitable for use in most severely cold regions across China.

Reach out to us for samples, datasheets and project quotation.