Managing water and moisture effectively requires high-performance membranes that work with your building's structure. Breather membranes form a protective barrier that keeps water out while letting buildings release trapped moisture and vapour.
The key to effectiveness lies in the membrane's ability to adapt to different weather conditions. It provides year-round protection against external elements while maintaining essential breathability that prevents internal condensation build-up.
What is a Breather Membrane Used For?
Breather membranes serve various applications in construction jobs.
- Protection against wind-driven rain and snow
- Prevention of water ingress into wall cavities
- Allow internal moisture to escape through walls
- Reduction of heat loss through air leakage
- Protection of insulation during the construction phase
Is a Breather Membrane Considered to be Waterproof?
A breather membrane offers high levels of water resistance but is intentionally designed not to be fully waterproof. Instead, these membranes provide a water-shedding layer that protects against rain, snow and wind-driven moisture while remaining vapour permeable.
The distinction between waterproof and water-resistant is crucial. A waterproof membrane would create a complete barrier, trapping moisture within the wall and potentially leading to dampness and mould.
Breathable membranes allow water vapour to escape while still resisting liquid water penetration. This balance ensures buildings effectively manage both external weather conditions and internal moisture levels.
What is the Correct Overlap Measurement When Fitting a Tyvek Housewrap Breather Membrane?
Horizontal overlaps should be a minimum of 150mm, increasing to 300mm in exposed locations. Vertical overlaps require a minimum of 100mm. Always lap upper courses over lower courses to ensure proper water shedding. At corners, extend the membrane a minimum of 300mm around each side.
Can a Tyvek Breather Membrane be Installed Behind Brick Slips?
Yes, a Tyvek breather membrane for walls can be installed behind brick slips, but proper installation is important. The membrane must be secured firmly with appropriate fixings. Maintain a consistent cavity width behind the slips. Also, make sure all joints and penetrations are properly sealed to prevent water ingress.
How Do I Ensure Proper Drainage Behind a Breather Membrane When Installing on Masonry Walls?
Creating effective drainage requires several key steps.
- Install with consistent tension: Maintain even pressure during installation to create uniform contact. Use appropriate fixings at regular intervals to prevent sagging or pocketing that could trap water
- Maintain minimum cavity: A clear 25mm cavity between membrane and masonry is key. It allows water to drain freely and offers ventilation for moisture management
- Fit cavity trays: Position cavity trays above all openings and junctions. Ensure proper overlaps and end dams to direct water out through weep holes
- Clear weep holes: Space weep holes at a maximum of 450mm intervals. Keep them free from mortar droppings and debris during installation for effective drainage
- Appropriate fixing spacing: Fix at a maximum of 500mm centres vertically and horizontally. Use corrosion-resistant fixings suitable for your substrate type
- Ventilation gaps: Include a minimum of 10mm continuous ventilation at the top and bottom of walls. It creates airflow that manages moisture levels within the cavity
- Lap direction: Always lap upper courses over lower courses. Maintain proper overlaps at joints and ensure vertical joints are staggered between courses
- Temporary protection: Protect exposed lower edges during installation. Use temporary covers if work needs to stop before the completion of the wall system