What is the best exterior insulation to put over existing double brick?

Andrew T

We are in the process of doing a major rennovation + second story addtition to a double brick 1940's bunglow. The inside will be be well insulated to code with an HRV, etc., but we also are looking to add 1" of rigid insulation (our builder has suggested 1" GPS) to the full exterior and finally clad it with Hardie Board. My question is around the best approach to the wall construction and application of the insulation & siding over the existing brick. I've done a fair bit of research and had a couple of people suggest that it might be a good idea to wrap the entire house (including the existing brick) with a house wrap used as an air barrier and installing the insulation on top of that.

This however, does not seem to be a common practice in the industry from what I can tell. So I'm wondering if adding housewrap directly over the brick is right thing to do, or is there a more appropriate approach to this scenario? The reason we are adding the insulation to the exterior it so help combat any possible freeze/thaw issues as well the continous insulation benefit. My main concern is around allowing the existing brick to breath. What would be the most appropriate approach for our situation here? Thanks!

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