Wall Insulation

Because of the new SB12 insulation requirements in Ontario, I was forced to do something different.  I always do what is best for my client based on their budget and/or requests.  My current client did not want to spend any more than they had to although they did not object to spending on insulation, if they had to.  Usually, I end up going over the minimum requirements but the Building Code people in their 'infinite wisdom' came up with the most ridiculously complex set of requirements.  We did not want an HRV for this addition, since the main house did not have one.  That meant that we had to have R24 in the framed walls. This is not a problem in that having a layer of rigid insulation on the exterior is always a good idea to create a 'thermal break'.   Only now we HAVE to do it.   I was going to put it on the outside but that means strapping for the siding.  My framer suggested putting 1 inch of AP Foil against the studs.  And then put the 1/2" plywood on top of the AP Foil.  Before the Foil they installed metal wall bracers.  This works really well as now you can do some nailing of the siding directly onto the plywood with some nails going right through to the studs.  This has now become my standard detail.  Amazing what you can learn after 40 years in the business!