How to choose building membranes: BBarrier contractor guide for vapor control

A thermal insulation layer is only as durable as the moisture management surrounding it. In pitched roofs and ventilated attic assemblies, warm internal air carries vapor that condenses if it penetrates the mineral wool. Conversely, external wind-driven rain and tile condensation must escape outward without dampening the insulation.

The two-sided protection principle

Moisture safety requires two distinct membrane layers:

1. Warm side (interior): A vapor barrier to restrict moist room air from entering the thermal insulation layer.

2. Cold side (exterior): A vapor-permeable, breathable underlay that sheds exterior water while allowing trapped humidity to diffuse out.

BBarrier specifications on file

EuConX Iso Kft. partners with Bilnur / BBarrier to supply certified building membranes for Hungarian contractors and nationwide EKR attic insulation programs:

• BBarrier BD70 (70 g/m² PE film): Installed on the heated interior side of attic joists and partition walls as a robust vapor barrier (DoP: `DOP_BBARIYER_BD70_20082025.pdf`, CE certified).
• BBarrier BK45 (45 g/m² breathable membrane): Installed on the cold exterior side to protect against draft and wind-washed water droplets while ensuring vapor permeability (DoP: `DOP_BBARIYER_BK45_20082025.pdf`, CE certified).

In typical EKR attic packages, 25 cm of ODE Starflex glasswool (2 × 12.5 cm) is paired directly with BBarrier BD70 and BK45 to guarantee an audit-compliant, certified installation file.

For technical data sheets, full roll dimensions, and direct project pricing, reach out at info@euconx.com or call +36 30 968 6527.