I've dusted off my calculator, made some tape measure measurements and drew a bunch of triangles on a sheet of paper. Using a standard 22.5° pitch, 38' wide from a base corner height of 8' tall gives a 12½' ceiling in the center section, which is what my workshop used to have before the weather rearranged the floor plan and has forced me to rebuild from the ground up. Now, down to the crux; 12½' ceiling is too high. All it does it makes it hard to change light bulbs and difficult to chase the wasps away. So, what say you for garage ceiling height?
No intention of putting a lift. The ceiling was previously 12'+ because the building was used to house a large RV.
Short person + Chopped , channeled ,sectioned and lowered custom = less ceiling height , and Less ceiling height = lower heating bills.
If you feel 12-1/2 feet is too high, you only have 2 choices to lower that height. Build shorter side-walls, or change the roof pitch. Even with 7 foot side-walls and a 22.6 (about 5-12) pitch over 38 foot width, your building is almost at 15 feet Roof Pitch Calculator | Pitches To Angle Chart (pole-barn.info)
I ran a couple calculations on paper. 22.5 degrees and 9.5 degrees (standard and minimum most shallow recommended). The difference in the roof center was minimal. I was considering just putting the primary cross beams in at 8' all the way across and paneling it all in, leaving the rest as attic space. Doing that would also mean installing an air conditioner would be a viable proposition. However, the interior portion of the roof would have 7' of rise at the apex, meaning I could go up to 12' in the center room. Having that open to the roof would be best, to allow convective circulation inside. I suppose the better question would be is: Who has an 8' ceiling in their garage and wishes it was taller?
Mine was 9 1/2' and I wished I had made it taller as I wanted a lift. Other than that it was fine especially as it had 8' overhead doors at either end.
I just measured my ceiling, it's not quite 10', looks are deceiving I guess. Not tall enough for a lift, but tall enough to use a cherry picker at full height. I was in a guy's shop once where the ceiling was so low he had problems using a cherry picker to pull engines with.
Mine is 10ft with 14.5 ft peak and not tall enough for a hoist , which would be nice now that I'm 64 .
The heat will stay up above you with a high ceiling. Be sure to put in a fan at the peek to draw the heat out and create a nice draft