Just finished wrapping my walkout basement walls and the difference is already showing

My house is older, built in the late 80s, and the biggest learning curve I had was realizing that just stuffing insulation in wouldn't cut it. Before I even started looking at batts, I spent a whole weekend just with caulk and expanding foam. Every single penetration, from where the electrical boxes were to the door jambs, got sealed first. That step, the air barrier, felt more important than the actual R-value of the stuff I installed. For the stud cavity, I used dense cellulose instead of rockwool because it felt easier to compress into the gaps without needing as much precise cutting. I ended up going with three inches, which should get me close to the target R-value we were aiming for. The concrete slab itself needed a seperate moisture barrier. Since my slab sits on a gravel perimeter, I used a specialized polyethylene sheeting to run around the entire foundation perimeter before laying down the new subfloor.

I found that the biggest headache was the utility penetrations. Just running a 2x4 through a plumbing pipe is simple, but sealing the gap around a gas line, even with a small foam backer, required careful trimming and plenty of high-quality sealant. My energy bills definitely dipped after this project, so the prep work relly paid off.

My situation was a bit diffrent since my basement alredy had some finished walls when I started. I wasn't dealing with open studs, but the concrete slab itself was the main issue for me. I found that adding insulation to the studs alone didn't do much becuase of the massive heat loss through the foundation. I decided to frame a secondary barrier inside the existing drywall layer.

Instead of just a standard vapor barrier, I used a continuous foam board system that clips directly to the joists. This really helped break the thermal bridge where the wood meets the concrete, which is a massive source of heat loss in this climate. I focused heavily on achieving a continuous perimeter seal where that new framing met the existing foundation walls, using backer rod and expanding foam in every single crack.

I realized that just trying to insulate the wall wasn't enough; I had to address the structure itself. Before I started, I was worried about condensation running down the drywall from the cool foundation, but since I achieved that continuous thermal break, the interior temperature stayed stable and I didn't see any signs of moisture migration after the first winter.

It took a lot of time getting those clips perfectly spaced, but the difference in how quickly the room responds to the thermostat was noticeable right away. It felt like a completely different approach than just adding batt insulation.

That strip of foam under the bottom plate is something I'd never heard of before. I'm redoing a basement room this winter and the bottoms of my walls always felt cold and a bit damp, never figured water could soak up into the wood from the concrete like that. I was just planning to lay the plates right on the slab. Does that foam strip go under every wall sitting on concrete, or only ones along the outside walls? Mine are all interior except the one on the walkout side, so I'm not sure if I need it everywhere.