The Drips of Condensation in the Tunnel

We went into the tunnel, our cold cellar, many times over this past winter, as we had pumpkins and spaghetti squash awaiting our use.  We noticed drips on the ceiling.

Thinking about it, we realized that the ceiling is only about a foot underground, so the winter cold was getting thru to our tunnel and the warm air from our entering the tunnel was condensing on the ceiling. We had the insulating umbrella on the tunnel near the house, but not at the end thinking that we wanted the earth temperature to keep the tunnel cool. Our problem was that there was not enough earth to keep it warm when 10 degrees F outside. 

To fix the problem, at the end of the tunnel, we dug down to find the roof of the tunnel. Then we applied a sealant on the end wall to repair any damages from digging down. Knowing at this point exactly where the concrete started, we were able to leave about 6 inches of dirt on top of the tunnel's concrete shell as we dug back about 6 feet. 

We installed the umbrella onto this portion of the tunnel and covered it back up.  If there is a portion of the tunnel without the insulating umbrella covering it, it now has at least 3 feet of hard packing clay 'dirt' on top of it. The new covering of the tunnel has 4 inches of closed cell foam on top which should give at least R20 insulation. The insulation is tapered where the dirt is deeper, such as on the sides and the end. For example, the end which is shown in the picture has 3 inches.

We also built a segmented wall around the end of the tunnel, so in addition to the 3 inches of insulation, there is over a foot of dirt and 16 inches of block wall before daylight. Notice the pink flags. These flags indicate the line of insulation at the end of the tunnel.

The next project is to complete the umbrella installation, that we started last fall, on the rest of the house. There may be some adjustments/repairs to the segmented wall, and a beautification process of the landscape once the machinery and dirt moving is done.