Pavadry Awarded BBA Certification

NBT Updates

We are proud to announce that Pavadry, our IWI solution, has been awarded BBA Certification, rubberstamping NBT’s rigorous approach to product specification and assessment.

The BBA tests construction products in a number of different ways including on-site evaluations, laboratory tests, quality management checks and inspections of production. BBA certification is a mark of quality, safety and reliability and is recognised by building control, government departments, architects, local authorities, specifiers, and industry insurers. Regular monitoring is carried out by the BBA and a comprehensive review is carried out every three years in order to maintain the certificate’s validity.

Pavadry – A Unique Solution

Pavadry is the first and only IWI system that has been assessed by BBA according to BS EN 15026. This is a relatively new assessment methodology and is widely recognised as the only appropriate standard for IWI assessment. It assesses the impact of a much wider range of moisture transfer mechanisms and sources than alternative methods, including the impact of rain on the external surface, which is now understood to be a much more significant contributor to moisture levels in solid masonry than occupancy related moisture. Pavadry’s BBA Certificate can be found here.



Pavadry is a dry-lined woodfibre board for internally insulating solid masonry walls and is a composite board of low and medium density woodfibre board (0.042 Wm/K & 0.13 Wm/K). The 12 mm layer of medium density hardboard is factory bonded to the internal face of the insulation which serves as a substrate for mechanically fixing plasterboard without pre-determined fixing points.

Some key points on Pavadry:

  • Condensation risk eliminated by innate material properties of the insulation rather than over-complicated detailing associated with vapour barrier based systems: Breathable system does not prevent the masonry drying to inside while absorbing moisture produced internally.
  • Load bearing internal surface – future proof in relation to fixing paintings and objects up to reasonably sized radiators without fixing back to the substrate, and thermally bridging the insulation This is a unique attribute of Pavadry that avoids the requirement for special measures for fixing items to walls following installation.
  • No adverse impact on internal air quality. Pavadry is made form 96.5% inert natural woodfibre with low formaldehyde; natural lignin from the wood is the principal binder. Inert fire retardant salts are the only additives. There is no danger of off-gassing of foaming agents or other chemicals used in the manufacturing process of other systems.
  • Solid & robust – highly impact resistant while providing a sense of solidity of the walls to occupants, with improved internal acoustics relative to other lightweight systems that can leave walls feeling hollow. The impact of isolating the internal space from thermal mass of the masonry is also minimised by the relatively high density and the high specific heat capacity of the material.
  • Simple and quick installation using a tiling approach, solidity of boards simplifies detailing and finishing at junctions, eliminates a whole stage of works relative to lightweight systems between studs, and consequently reduces measuring up requirements for stud placement.
  • NBT specification and installation support ensure that specification is appropriate for the building and its context – WUFI dynamic hygrothermal modelling, and the system is installed correctly.