Smart vapor barrier
Smart vapor barriers are appearing in the building construction, mainly in Europe to improve moisture performance of building envelope. They are based on the variability of permeability according to relative humidity levels.This trend should and could be transferred and developed for Canadian market. The cold climate and wood frame wall make it a potential source of gains.
" CertainTeed has begun marketing MemBraina, developed by a German subsidiary of CertainTeed's parent company, Saint-Gobain. This so-called "smart" air/vapor barrier, made from 2-mil nylon, becomes more permeable as the humidity increases. It may even be effective as an exterior housewrap product in hot, humid climates" -- http://www.shelterecology.com/articles/art_Moisture.html
See 
PATH Technology Inventory on toolbase.org
Related References:
- ASTM , (2001), Performance of exterior envelopes of whole buildings VIII: integration of building envelopes
- Kunzel, H. M., (1998), The smart vapor retarder: an innovation inspired by computer simulations
- Kunzel, H. M., (1998), Smart vapor retarder: an innovation inspired by computer simulations
- Kunzel, H. M., (1998), More moisture load tolerance of construction assemblies through the application of a smart vapor retarder
- Kščnzel, H. M., (1999), Flexible vapor control solves moisture problems of building assemblies - smart retarder to replace the conventional PE-film
- Messadi, T. and Augenbroe G., (2001), A configurable smart facade unit for on-site calibration and control optimization