As of January 1, 2012, the Ontario Building Code has made significant changes to its insulation and building envelope criteria.  In the past a rating of R-20 was the benchmark for residential walls.  This has now been changed to an R-24 for renovations and R-27 for all new construction.  Attic spaces have been changed from R-40 to R-50.   Both of these changes can effect the way your house needs to be constructed.  Be informed about your project, call WYGA.