FAQs

NO. MEDITE VENT is a panel that can be used in humid (service class 2) conditions.

MEDITE VENT is produced to a lower density than most standard MDF to provide lower vapour resistance while maintaining sufficient strength as a racking panel.

As with all wood-based panels for use in humid conditions wetting should be avoided. If the panel is wetted during installation it is recommended to allow the panel to dry before the permanent covering is installed.

MEDITE VENT is manufactured using the same moisture resistant (and no added formaldehyde) resin technology as SMARTPLY MAX OSB/3 and SMARTPLY ULTIMA OSB/4. This makes it suitable for use in Service Class 2 (humid) conditions and suitable for use as external sheathing panel in timber frame structures. MEDITE VENT must be protected by a suitable breather membrane and maintained in Service Class 2 conditions in the finished building.

NO. SMARTPLY AIRTIGHT is certified as an airtight panel. MEDITE VENT is not airtight.

MEDITE recommends that breather membranes from reputable suppliers are used, the membrane should be:

• CE marked,
• Compliant with the requirements of BS EN 13859-2:2014 - Flexible sheets for waterproofing. Definitions and characteristics of underlays. Underlays for walls.
• If a high reflectivity membrane is used, the thermal performance should be measured after ageing of the reflective surface.

Most breather membrane supplier would comply with those performance requirements.

NO. MEDITE VENT can be used as the only sheathing panel in as it is a racking panel tested to EN 594. It is a breathable panel suitable for use in service class 2 conditions.

In cold temperate climates in Europe MEDITE VENT should be installed on the external side of the wall build up to allow water vapour to escape to the outside and avoid condensation in the insulation and structure.

YES. The certified passive house wall systems are certified with SMARTPLY AIRTIGHT and MEDITE VENT included. All other wall and roof elements are generic, with only the minimum thermal performance as a requirement.

MEDITE VENT was not designed as a roof sarking panel. If used in roofing applications noggins are required to support all edges (no T&G option available) and standard roofing recommendations (fixings, expansion gaps…) should be followed. MEDITE VENT is only manufactured in 12mm thickness, if used in roofing applications spacing between supports and load bearing requirements should be checked before use.

SMARTPLY AIRTIGHT is an OSB/3 panel which achieves category 1 racking resistance. MEDITE VENT was tested to EN 594 and also achieves Category 1 racking resistance, using standard timber frame fixings. For further information on this please contact your local Technical Sales Manager.

SMARTPLY AIRTIGHT has a very high vapour diffusion factor (dry cup 750) (i.e. it fulfils the requirement of a vapour control layer) to prevent excessive moisture entering the building fabric. On the other hand, MEDITE VENT has a very low water vapour diffusion factor (wet cup 9.7) (i.e. it is very ‘breathable’) to facilitate fast drying of built-in moisture and reduce the risk of interstitial condensation in walls. For further information and test reports please contact your local Technical Sales Manager.

MEDITE VENT is not an airtight panel and so will let air flow go through.