Rafter Ties

[cibula11]

The ceiling joists in our garage are 2x4's and I would like to get rid of them and raise the ceiling using 2x8's as rafter ties for our conversion. I know about the 1/3 rule when installing ties. The rafters currently (2x6) span 12 feet from top plate to ridge board. I would like to have the 2x8 rafter ties at the 4 ft mark, but they would not be in the 1/3 range, but rather right AT the 1/3 mark. Is this still acceptable?

If not, could I have part of the tie in the lower 1/3 and part above it? If I were to have the entire rafter tie in the lower 1/3, I'd have a door opening of only 79" rough opening.

 

[911handyman]

. Those 2x4's act as a bottom chord on a truss keeping the build plumb and level. I think you are trying to create a vaulted ceiling or A frame type with a door for upstairs is that correct. If not where does the door come in. You will need rafter ties unless your ridge beam is self supporting. You can only install the 2x8's at the lower 1/3 from the top plate. Hope this helps

 

[cibula11]

Handy man, you are correct. I planned on adding 2x8 rafter ties. So I could NOT add the ties above that 4 ft. line? The door will come into the space near the point where the vaulted ceiling will flatten out.

The problem is that if I put in a regular (6'8") door, when you open it, you could be staring at 3-4 inches of ceiling. If I raise the ties, I get outside of that 1/3 rule.

My option are to shorten the door (not sure inspector would approve of that)

Lower the ties so they are exactly at 80", keeping most of the tie in the lower 1/3 but also having a portion in the upper 2/3 (if that makes sense). Also, not sure if inspector would like that option either. Any idea of that would still suffice?