my wife wishes to add a family room to the house, she wishes it to have 10 foot high 2 x 6 inch walls 24 feet apart with a catherdral ceiling, she is still working on the length. I've found a picture of a vaulted parallel chord but no other info about it. With all the potential problems concerning insulation and ventilation I feel this would be the best way to go. Do you have any info on constructing these chords for 24 feet length and as high as possible and what to avoid etc?

IGG

Either that or a scissor trusses. Same concept but better load bearing and more ventilation space. Easy to run wire and insulate. I have them in a N. GA mountain cabin, 7/12 outside pitch, 5/12 inside, 13 ft. high in middle, 28 ft open.