It looks like Barney threw up on my basement walls doesn't it? We've had the three exterior walls covered with spray foam insulation. We debated going with batt insulation, but in the end, we felt the additional investment in spray foam would be worth it. Because spray foam can adhere to almost anything and expands to fill any crevice or irregular shape, it can provide a 100% air tight seal resulting in reduced HVAC costs.

As well, the 3" of foam applied acts both as an air barrier and a vapour barrier so there is no opportunity for wall condensation that can result in mould or mildew. Oh, and it is also more resistant to rodents and other creepy crawlies.  Did I tell you that we found a mouse in the basement last fall? YUCK - so rodent resistance is very high on my list :)

This is going to be one toasty warm basement. Since we had the walls open (see, there's that scope creep popping up again), we had AirForce Insulation also spray the first three feet under the kitchen exterior door. When we renovated the kitchen three years ago, we thought of adding in-floor heating under the floor tile but it was late in the game - we would have to bring the electrician back in and delay the drywall. So we decided not to do it, but since our galley kitchen opens to a pair of sliding doors at one end, we've been living with a cold tile floor every winter since. Now with the spray foam underneath, we could make it at least a little bit warmer.