Ventia Black - Self Adhesive Underlay (1.5m x 50m / 75m²) is a premium, fully adhered weather barrier and vapour-permeable membrane imported and supplied throughout New Zealand exclusively by EBuilt Ltd (EProducts NZ Ltd).

Engineered in Poland by mdm NT—one of Europe’s leading manufacturers of advanced technical building wraps—Ventia Black represents state-of-the-art building envelope protection. Manufactured under a sustainable zero-waste philosophy that recycles post-production materials to eliminate factory atmospheric emissions, Ventia Black is purpose-built to meet and exceed New Zealand Building Code requirements. It delivers an airtight, water-resistive, fully bonded seal for modern rigid substrates, mass timber, and high-performance building systems.

Advanced Technical Quality & Material Construction

Ventia Black combines high mechanical strength with a full-surface adhesive backing:

• Micro-Porous Core Layer: An advanced functional membrane that acts as a continuous water-resistive barrier while providing exceptional vapour diffusion to let trapped structural moisture escape.

• Full-Surface Self-Adhesive Backing: Features a high-tack adhesive layer protected by a split release liner. This enables fast, clean, and accurate installation directly onto rigid substrates without requiring mechanical fasteners that pierce the weather barrier.

• Robust Physical Profile: Supplied in generous 1.5m x 50m rolls covering 75m², with a total membrane thickness of 0.6 mm and a nominal mass of 130 (+50) g/m². It delivers outstanding tensile strength (280 N/50mm machine direction / 190 N/50mm cross direction) and nail-shank tear resistance (135 N machine direction / 170 N cross direction) to withstand demanding job-site conditions.

Core Performance Benefits

• Continuous Air Tightness & Weather Protection: By bonding directly across the entire substrate, Ventia Black forms a seamless, gap-free seal that prevents wind-wash and air leakage. It achieves Class W1 liquid water penetration resistance and maximum air penetration resistance, protecting wall and roof structures against wind-driven rain and draughts.

• Exceptional Vapour Permeability & Breathability: Unlike non-breathable traditional self-adhesive barriers, Ventia Black features an ultra-low vapour resistance (Sd value of 0.090 m). This allows internal moisture-laden air to diffuse harmlessly through the membrane, preventing interstitial condensation, timber rot, and mould growth in high-performance building envelopes.

• Versatile Substrate Compatibility: Formulated for direct adhesion to Rigid Air Barrier (RAB) systems, plywood (minimum 7 mm), fibre cement sheathing (minimum 6 mm), and OSB boarding across timber or steel framing. It is fully compatible with leading New Zealand rigid sheathing systems, including James Hardie, GIB Weatherline, and Ecoply.

• Engineered for Mass Timber & Off-Site Construction: Ideally suited as a fully adhered roof and wall weather protection layer for Structural Insulated Panel (SIP) construction and Cross Laminated Timber (CLT) builds, shielding mass timber elements from weather exposure during and after construction.

• Temporary Weathertightness Protection: Provides reliable temporary weather protection on site, allowing internal construction and fit-out trades to proceed before primary exterior wall claddings or roof coverings are installed.

• All Wind Zones & Fire Safety: Appraised for use across all New Zealand wind zones, up to and including Extra High. Additionally, Ventia Black is fire retardant with a Flammability Index of less than 5, satisfying interior surface finish safety requirements for flexible underlays.