I believe it's 20x30. Insulation is non existent and since the slab for it was not either poured level or it settled uneven there's big gaps in the big sliding doors. We had the ends put on recently and the contractors told me about the unevenness. They tried their best, but it is what it is. I plan on throwing up some insulation and plywood on the vertical walls. Not sure about the foam on the arch though. I also have lots of roof leaks to deal with. Couldn't tell they were there until it got sealed from the weather. I'll seal them up this summer.

Got a spare oil heater huh Don?... lol