I’ve searched e-bay… and the net… I have about 80 2″ sq 1/4″ wall steel fence posts to put in… every 4th post will be 6″ sq these will be set in concrete…
in the past i’ve had good luck drive’n 4″ wood post… better & faster than setting them in concrete…
most of the chain link fence contractors around here drive the posts with a hand held hydraulic post driver that operates off their bobcats hyd system…
with the rockhard ground i have that has few if any big rocks to hit i even considered using a 1.5 auger i have (predrill the hole) then drive the post? i can drill 24″ with the bit i have…
or i can drill 80 6″ holes and set them in concrete…
does the concrete really do anything other than “lock/set” the post in the hole… anything more than if the post was driven into the same ground? what am i missing here? does the mass of the concrete add anything?
thanks in advance
p
Replies
I'm currently setting 6" wood posts in washed crushed stone (auger hole, place post, place stone, compact). These posts were previously buried in dirt for a decade or few, little degradation but I soaked them in an oil bath anyhow. Solid foundation for my roof. Set one wrong and was surprised how difficult it was to extract.
For small fence posts, I'd use a heavy loader bucket 'cause I've got one and don't have a post driver. Put a few tons on top and posts tend to go down. Requires a helper (not under the bucket) to ensure they're plumb.
Concrete'll do a good job of keeping the water with the post. Also makes the post more difficult to remove. I've pulled a few.
Your auger sounds good. so long as you don't leave rain water standing inside your posts.
PAHS Designer/Builder- Bury it!
Edited 8/18/2007 11:17 am ET by VaTom
few if any big rocks to hit
Around my place, I'd hit a basketball sized rock 1 out of 5 times, so ususally just dig holes if needed.
Have driven a few posts with the backhoe bucket similar to Tom, but cant keep any perfectly straight.
My experience with concrete around posts (esp for the 2" guys) is that the concrete provides a larger bearing surface against the softer dirt. Lots of soil here is cemented hardpan, so if it is wet down good when it goes back in the hole it is about like concrete.
I'd try a few of each of the methods you described, and go with the one that works best. I dont have a percussion hyd. driver, probably not worth trying to scrounge one for 80 posts.
"does the concrete really do anything other than "lock/set" the post in the hole... anything more than if the post was driven into the same ground? what am i missing here? does the mass of the concrete add anything?"
Good question. I've always wondered the same thing.
Back in 2001 in Edmonton we had to put in several hundred round pipes 2 1/2inch(inside diameter) by 1/4 inch thick by about 4 feet long into the ground to support hundreds of 20 foot flag poles. I hired a big fence company to do it and I was expecting them to have either a post driver on a skid steer or an electric pounder that vibrated the pole into the ground. 2 really muscular guys showed up with a 2 handed sliding post driver and between the 2 of them they drove in the pipes so fast I couldn't believe it.
I was really sceptical about them being plumb because any problem would be amplified with 20 foot flag poles all in a row, Well, I checked and they were all bang on.