I've picked the highest elevation, which is perhaps 6' above the top of the stream bank, and in the past the water hasn't reached the building site level--not even when Katrina hit. I would like a pier and beam foundation, but do I use a sono-tube method or cinder blocks. Most everyone uses cinder blocks, here in East Texas, but I'm not sure they're the best method, especially if there's any force of water against them.
Also, which sort of professional should I try to find to install this foundation? If it's the consensus that cinder blocks are substantial, who is the best at doing this type of building?
Any help is appreciated. I don't want any sleepless nights, wondering if my tiny house will float away. However, my budget is as tiny as my house, so cost is a factor, too.
Concrete block, especially filled with grout and rebar are very subtantial. You just have to make sure you have enough depth since you already have a substantial footing under them.
Sonotubes are great IF they have enogh bearing area and depth to resist and stream flow and erosion, which would be likely.
Bottom line - The block piers have more vertical load capacity. If you rent an auger for the tubes, then you can go deeper and they will work in wet soil.
The best thing I saw on the coast of Mississipi after checking 300-500 homes after Katrina was 8"x32" concrete block piers on spread footings 6-8' deep. They were perpendicular to the surge and had maximum strengrth to resist the surge and debris. Wood piling was worthless and snapped at 5-6' above grade - good fuel for a fire pit. Steel leaned and bent and had to be scrapped. Poured or driven concrete leaned because of the lack of soil support (too narrow) and not the 15-20 depth that was necessary. - This is based on a predictable flow direction, which may ne be possible with a local stream.
Just some observations.
For a 16x24, you may just want to takes you chances on the history being repeatable.