Spano Durelis Vapour Block

DURÉLIS VapourBlock is a 12mm, 2400 x 1200mm high density chipboard with a factory fitted transparent airtightness and vapour control layer, TOPFINISH, on one side. This surface applied finish guarantees consistent airtightness and vapour control. It also eliminates the requirement for additional vapour control membranes to be applied on the internal side. VapourBlock is for internal use. It is classified as a structural board which is suitable for use in humid conditions (P5) equivalent to OSB3.

Delivering higher levels of airtightness is central to realising low energy or Passivhaus levels of energy performance in buildings. This can be attained using a range of materials depending on the construction type, namely, a continuously sealed vapour control layer, a continuous Plaster layer directly applied to a masonry wall or an airtight structural board, such DURÉLIS VapourBlock. A structural board has the advantage that it fulfils 3 primary requirements in one step, namely:

- Vapour control,

- Structural requirements,

- Airtightness.

Up until recently it was generally accepted that taped and sealed 18mm OSB3 was a reliable airtightness layer, with which one could attain the stringent Passivhaus criteria for airtightness of less than 0.6 Air Changes Per Hour at 50 Pascal. Experience on site coupled with a study by the Building Physics Laboratory at the K.U. Leuven showed that OSB sheaths are not always adequately airtight. It concluded that, if the manufacturer of the panel cannot provide an airtightness guarantee, an allowance must be made for significant air leakage directly through the panels themselves.