I'm adding a 10x10 (100 ft sq) shed workshop to my yard. Walls are 2x4, 16"OC. Rafters are 2x6, 24"OC. I will be insulating the shed and adding climate control so I can use it year round. I'm in Ontario, Canada FWIW.
Currently the rafter ties are about 1/3 of the way up the rafters, creating an area of sloped ceiling on either side of the shed (Blue rafters/ties in pic). I'm wondering if I'm better off adding ceiling joists in order to create a flat ceiling for insulation, essentially converting the rafters to trusses by adding a horizontal span across the building, and tying it to the existing rafter with a vertical member (shown in black in the pic).Wall height is 8ft, so plenty of headroom without the sloped ceiling areas.
If I take this route, are 2x4 members sufficient?