For concrete basement walls, we typically use 2" rigid foam board (about R-10) installed directly against the concrete.

  All seams are taped, and gaps, corners, and penetrations are sealed with foam. This creates a continuous insulation and air-control layer, helping prevent warm, humid indoor air from reaching the cold concrete surface.

  Why not fiberglass?
We don't install fiberglass or mineral wool directly against concrete. Moisture can reach the cold wall and create condensation. Batt insulation can be used between studs, but only as part of a properly designed wall assembly.

  Where do we use spray foam?
We typically use closed-cell spray foam at rim joists, around pipes and penetrations, and in areas where rigid foam is difficult to install and seal properly. The thickness depends on the location, required R-value, and wall assembly.

The goal isn't just to make the basement warmer. It's to build a wall system that helps control heat loss, condensation, moisture, and mold risk.