I have an existing sunroom off the back of my house, it's 13'8" deep by 17'6" wide. The current "foundation" runs 2/3 of the addition perimeter with one side open to access a partial dug out crawl space; which has an average of 4'6" headroom. The 2x8 joists are unevenly spaced but average 14" spacing. I'm using a trial of SmartDraw and I've attached a jpeg of the drawings. 1" = 4' The brown is existing framing and the yellow is planned. I basically plan on cladding the rim joists with new 2x8. Creating a 20' beam with 3, 2x10's, glued and nailed. Sitting on 4 6x6 PT posts on metal saddle brackets set into my 18"x18", 6" deep square footings. I'll also be putting another 2x10 fastened to the house wall under the existing ledger board with 6" Lags offset every 12". Does this look good? Any comments would be appreciated. Thanks.