Step 3: building wall frames
The walls are basic, 2 inch by 4 inch stud walls with studs built on 16 inch centers. There are headers built over each of the openings; the door opening on the back wall and two (2) side openings. The side openings were constructed in case I wanted to dry boards longer than the kiln or to extend duct work to the work shop.
I also framed in two (2) openings for the fans that measured 18 inches by 18 inches.
I also cut a 4 inch by 4 inch post diagonally in half and lengthwise to create a header for the front and back walls that would match the slope of the roof. Regarding the slope of the roof, the VT plans state that for the best solar efficiency, your roof should slope at the same degrees as your degrees of latitude. It would be approximately 39 degrees for us; however, 45 degrees is simpler to build, will work OK, and is what I constructed with.