I need help in planning my piers and beams. I am building a 30x24 cabin w/loft running the length. The plans I have call for 29 piers. the spacing on the lenth are 7'6" and on the width = 8'. The inteior piers are 7'6". I think this is a little much! The outside beams will be 6x12 PT and interior will be 4 x 6 pt. the floor joist are 2x12 on 16" center. the piers will be 10" w/ 6"x6" posts on the outside and 8" with 4"x6" post inside.
The building inspector said to use 10 piers!
what do you think?
29 is alot of piers, thats alot of digging,a lot of concrete.
To understand your options you will need to do a full load trace through the building using the local dead and live loads. Then you can trace the loads to the beams and design the supports and spans. You can often trade off deeper beams against fewer piers if you have good bearing soil. However, this is not something a builder or designer can do "by the seat of their pants".
You should visit a practical engineer who may be able to do such a trace and redesign while you wait. I find I get better value when I sit there and work with the engineer. At the same time the two of you can look at racking resistance and if the house has enough bracing against sideward (wind and earthquake forces). These will also have local design criteria that can vary in the next county.
This kind of customization of a stock plan is a good investment in long term durability and may even end up costing less to build than what you have now. Such a design review may only take an hour or so if all you need is a grid paper layout rather than new stamped drawings.