Hi,

I would like to discuss a budget-saving building method on foundation. I am planning to build a 16' X 24' shop using a 3-bent with queen post design. 2nd story will be a small living quarter (kitchen/bathroom in a 12'x16' section and living room/bed in other 12'x16' section. On the slab, you notice short sill on front.. I am planning to add 4x6 post on the end to support the garage door and 2nd floor beam.

I made a quick drawing using the Sketchup and without putting too much effort into the TF design because my main focus was the foundation itself.. but to give you some rough idea.. the structure will be of 6x6 sill plates, 6x6 posts, 6x8 summer beam to support 2nd floor joist, and a 4x6 rafters.

I want to use Alaskan slab for the shop using 4" thickness. The question is to support the structure using 24"x36" at the edge to support the load. See first pic below on left side. Or the 3'x3'x3' footing seen on 2nd pic below.



The reason I came up with 3'x3'x3' is because when I built a huge outdoor stage which is 40' wide and 20' length.. the architecture had me using 8"x8"x24' treated posts at front corners to support a 40' "board" so it can support the 24' roof rafters (lean-on design). Because it is outdoor in the open and exposed to high wind, a 200MPH wind load requirement design was kept in mind, I had to make a 4'X4'X4' concrete footing for each post. At bottom of the post where the pouring would be, 4-5/8" rebar was drilled through and it was 3' long. So duplicating this idea, I was thinking it might work for the 16'x24' TF structure design? I was using 3'x3'x3' at each post so the anchor can hold down the sill plate and steel strapping to hold down posts. The difference between bottom one and above one is that bottom one needs only 11 yards while above needs almost 19 yards. That is almost $700 in saving.



I am curious on your input!