What is a vapour permeable breather membrane？
I Introduction for the vapour permeable breather membrane
Vapour permeable breather membranes allow water vapour to pass through the membrane, out of the roofing system or walls. It help to manage condensation risk by allowing water vapour to easily escape – reducing the risk of moisture accumulation in the building structure. *In conjunction with sealed joins and penetrations.
vapour permeable breather membranes are typically used as a protective second skin behind lightweight wall claddings and underneath roof claddings. Enviroseal vapour permeable membranes combine high-tech vapour permeable films with protective non-woven spun bond fabrics. The vapour permeable film contains millions of microscopic holes that are large enough to allow water vapour molecules to pass through them, but too small for liquid water to penetrate. The result is a product that allows the transport of many times more water vapour than a traditional ‘breather’ product, prevents the entry of liquid water and also has the ability to prevent the transport of air which limits the passage of uncontrolled water vapour and dust.
II function for breather membranes and where use it?
The function of breather membranes is to provide a barrier against water penetration from the outside while allowing migration of water vapour through the membrane from inside the building.
While being typically associated with rainscreens, their use is not always well understood and they are not always required.
Breather membranes are installed on wall or roofs. They are used on external or cold sides of the wall insulation, under the outside surface of the external lining or roof tile or even cladding.
III Features for breather membranes
1 Low vapour resistance
2 High Resistance to Tearing
3 BS5534 annex A wind uplift compliant
4 Watertight
5 Airtight
6 Flexible
7 Durable three layer construction
IV Benefit during and after construction
1 Protects the frame and roof structure from the elements prior to the application of external cladding.
2 Improves on-site work flow efficiency by allowing internal trades to commence work before the external cladding is applied.
3 Reduces the risk of moisture and mould related issues compromising the structural integrity and health of the occupants.
4 Improves air tightness which in turn improves energy efficiency, but still allows vapour to escape without condensing on the inside of the building frame.
5 Protects the interior of the building from moisture and dust entry from the outside environment.
V The reason we use it
Building Regulations demand ever higher thermal efficiency.
Today’s building envelopes are becoming increasingly airtight.
Whilst beneficial for the energy performance of our homes, airtightness makes careful consideration and management of moisture more critical than ever.
Studies have shown that ventilating directly above an insulation layer can reduce its thermal efficiency.
Which means more and more people are opting for an un-ventilated roof. This is where breather membranes come in!
They also protect against condensation that can cause mold and structural damage from rotting timbers when a roof is not able to dry out sufficiently.
VI Introduction for DERFLEX
DERFLEX is a professional manufacturer of . We have our own factory, which is located in Zhejiang province, China , with 7 production lines, the supply capacity is 300,000sqm/month. We can produce different kinds of wide format digital printing media. Such as coated Frontlit, backlit, laminated PVC tarpaulin, blockout,mesh,self-adhesive vinyl, one-way vision, perforate vinyl, wide format print cotton canvas, PVC coated tarpaulin, photo paper, reflective material, projection screen fabric. 
Our main product is PVC tarpaulin and it is widely used as truck/trailer/container cover, tents, pallet cover,strip garden fence,
awnings, inflatable products, adumbral materials for building facility and house.
For further business communication, welcome to contact:
Tel: +8617316447897(whatsapp&wechat)
Email: ellaine@derflex.com
Web: www.derflex.com