Can you add external insulation to a brick home?

You can for sure insulate the exterior of a painted brick house, in fact that would probably help preserve the bricks. Be very careful when painting bricks to choose the right materials  since most paints will  traps moisture, and in a cold climate like Chicago, the freeze / thaw cycle can cause them to crack. So insulating the exterior of  a painted brick wall is actually a good idea to help protect them.

When insulating the exterior of an existing house we often recommend Rockwool, it’s a recycled mineral wool rigid insulation , read more here – 

The difference between Polyiso, EPS & XPS Foam Insulation & Styrofoam

Rockwool isn’t harmed by moisture and it lets moisture move right through it, which is a very good thing to use for an exterior insulation renovation project since it doesn’t trap moisture in any wall system. You could apply Rockwool (rigid Comfortboard, not batts) then a weather barrier / air barrier, then strapping and your final siding.

The only thing that might prevent you from doing this are municipal bylaws, which sometimes in older neighborhoods they often want to maintain the community aesthetics.

One thing we would strongly urge you to do, would be to complete the job, and do all the surfaces including the foundation. If you insulate the bricks from a few feet up and don’t do the foundation, there will be so much thermal bridging from the warmer bricks to the colder foundation that a lot of your efforts will be undone in a way. It would be a bit like buying an awesome new winter coat, but then only wearing a pair of shorts. You need to complete the deal. 

Here are a few other pages that you should check out to make sure this works out properly – 

• How to install siding so walls can dry
• Choosing the right weather barrier