So... I'm a little down on my luck with my accident and all. A quick and easy comes my why. Yeh right! 520 sq' addition should only need footing pads. But, we got engineers and the likes. Mine shafts are the cause. Nanaimo and the coal boom left a cottage cheese like maze down under. The local ground penetrating radar (GPR) surveyor opens up our way forward. Adding a reinforced foundation is a must. Anyway, nice job just waiting for permits and off we go! 18"min Foundation walls. x2 - 15 mm in the bottom and 12" centers for the Vert. 12mm solves the mine shaft worries. With 30' long trusses and 2.4/12 slope. Winter Guard must go on. Little bit of experience and educated tradesmanship, helps tie into the existing Post and Beam structure. And we have a Project. I love my Job!! Just gotta make lock up before next snow! lol. Have a peak...