Building Science Corp’s recent study on humidity in walls in the North East was interesting, but it only looked at “…relatively vapor open Class III vapor retarder (latex paint on gypsum board) as the interior vapor control layer.” Unfortunately for Ontarians, the building code requires a vapour barrier in many cases, so the results of that study aren’t really applicable.
Adding insult to injury, Ontarians don’t really know what IECC climate zone they’re in. What we do know is that Ontario’s climate is both “cold” and “wet” which means high R-value wall assemblies have a lower drying potential in cold months, which can make them prone to condensation.
IECC climate zone map doesn’t cross political boundaries…
Now the good news…
The Canadian Wood Council and Chris Timusk of George Brown College have teamed up to assemble a data base of hundreds of wall assembly variations with WUFI analysis for each scenario. This is a brilliant resource for energy modelers as it gives a WUFI simulated durability analysis and the composite R-value of the wall assembly – a fantastic resource!
Below is but one sample of hundreds of variations:
