I own an older duplex that has a cold room or “cantina” in the basement. The cantina is right below my front porch (see picture below). I recently noticed through a small hole in the gyprock / sheetboard, that there was frozen condensation on the wall, essentially frost. I managed to remove the gyprock around that area (there happened to be a window there) and noticed that there wasn’t enough insulation around the window so I bought a can of spray foam, and filled it up. It helped a little, but I still notice that the frost keeps re-appearing when the temp gets fairly low outside (below -10 c or 14F). The frost isnt as apparent when its around 0 c or 32 F. Although the cantina has gyprock on all the walls, I can stick my finger in a few random spots, and I can feel frost here and there, it doesn’t seem that the window area is the only affected area, other areas as well seem to have frost too.
The cantina is not heated, and there really isn’t any insulation, its essentially cement walls. I don’t plan on heating it either (use it to store ski/snowboards and boots etc…). Sometimes I leave the door to the cantina (door access via basement) open as heat trickles in from the basement, this actually helps reduce the frost quite abit.
How do I avoid the frost from re-appearing? Should I insulate the room with either rigid foam board or pink wool insulation, and then apply a vapor barrier over that, and then re-install the gyprock board that’s there?
What would be the best type of insulation, rigid foam board, or the pink wool type of insulation?
I’m fairly confident that there are no cracks in the cement structure, as there are no water leaks in the spring.
Thanks allot, any help is appreciated.
Outside view, its below the porch...
Frost on wall