I'm building a 12x24 building with 8' of the roof 10psf. being supported with one 2x12 on each side cantaleverd 8'from the other 16' of the building. Will a single 2x12 on either side of the 8 x 12 roof support the roof being cantaleverd?
The International Residential Code (IRC) that governs most residential construction in the US provides for short cantilevers in some situations. 8'-0" cantilevered from a 16'-0" is way out of bounds for IRC tables. You would need an engineer to size beams for this cantilever.