Ceiling joist question

[MattMM]

I am getting ready to start building a small addition onto my garage and have a question about the ceiling joists. The addition is going to be 8'x10' with the ceiling joists running the 10' length perpendicular to ridge of the roof. Studs, rafters, and joists are all 16" O/C. The way that I have the design drawn up now has the joists sitting on the top plate of the wall next to the rafters. My father in law suggested that instead of the rafters sitting on the top plate, I should instead attach them to the wall studs directly below the top plate to gain some additional attic space. Does anyone see any issues with doing this? I would definitely like the additional space above, but I don't want to compromise the structure in any way.

 

[PAY22]

I have a classic car and want to install a lift in my 2 car garage built in 1939. To install the lift i would have to remove the 3 rafters running from wall to wall.is there another bracing system i can use to replace those rafters. Pay22

 

[GBR]

Welcome to the forum, both of you!

Matt, the rafters are required to sit on the top plate of the two plates or within 1" of the studs below if one plate is acceptable to your local Building Department. IRC 602.3.2X, steel ties used if one plate on top- -- 1-1/2" min. bearing for end of rafter = 802.6. The rafter/tie (every 4') or rafter/ceiling joist connection is critical so the walls don't spread and collapse: Common Nails Required for Rafter Ceiling Joist Heel Joint Connections - Engineers Edge

Pay22, check locally with the B.D. as you are in a seismic zone, same as me. You might be able to raise the joists to stay in the bottom 1/3 of the total rafter rise: Myers Construction Company

Gary