I'm burying the 6x6. UC4C - like 4 times the amount of preservative in PT wood in stock at lumber yards and such. The existing 10 posts are 30 years old and fine and probably not near the UC4C treatment. I am considering digging a foot or so around existing and adding some of the wrap stuff.
16" is big, even for the towable, depending on your soil conditions. I own 2 handheld augers, a one man and a two man and 8" is as big as I like to go with them. I've rented the towables and they are good but depending on soil conditions I would say 10-12" max is what I'm comfortable with. I've use augers on mini skids, skids, and mini excavators before and that's the only way I would do a 16" hole, especially that deep. We did a leg tower for a farmer a few years ago and di 48" diameter 16' deep holes for that. Hired that out to a guy that brought in a big excavator and big auger. The noise of the concrete filling those tubes was loud but trucks emptied quick filling those.
Do you consider the trailer mounted 16" auger with 15hp engine pictured above, to be manual?
This one?
Yes
When that thing hits a rock/root what do you think happens to the end you're holding onto?
I wish and may spend it but hiring it has to be near $1500, and the rental is just over $100. No guarantee if no rocks but other, deeper excavation has revealed all sand.
Fist sized or boulder sized?This one?
Yes
When that thing hits a rock/root what do you think happens to the end you're holding onto?
I've used the towable trailer auger many times for fence and deck posts using 8-12" augers. I would not try a 16" on it unless your soil is very soft. I've gotten a 10" auger stuck in the ground before and had to use a skid to lift the auger out of the ground.
Rent machine w SSQA auger and be done with it. 5' deep holes are hard and depending on your soil can be pure hell. I'm still in the process of building a perimeter fence and in fact getting dressed to go dig the final two holes of the gate entry. 4" and 3.5" pipe set 5' in compacted dry red clay. We used a one man auger for areas of inaccessibility. We fought for every inch some days with a rock bar, sharp t shooter shovel and the auger. To date we have dug 21 such holes 5' deepx9". For areas we could get a machine I rented a Bobcat Toolcat twice and after I bought my tractor I used the SSQA FEL auger. Both machines made posts easier, even if the ground was dry and compacted.
All sandy. Dug - had an excavator - for a 28 x 32 building with 4' deep footing and cut into hill 2 to 3' - on small boulder. Maybe a few fist sized rocks.
You’ve got several more year’s experience than I do, but I don’t think I’d try that without expert assistance, or paid help. If your rental yard is that far away, sounds like you are kinda rural. Seems like somebody closer would have a bobcat with auger, or an auger of some size, for a reasonable price. I’m on the edge of rural, and have three or four earthworks guys close.
I'd like a 14 or 16" round footing. I calculate the load at around 3000 pounds and the soil is good for at least 3000 PSF so 14" is about right. Since I can't imagine it being occupied (40 psf) at same time there max snow on roof (60 psf) I'm not worried much about 12" round.
