08-24-2009, 06:01 AM
I tried to dig a post hole for a gate post in pahoehoe using a small to medium sized hammer drill and an o'o. I gave up. I was making some progress but is was extremely slow going. I think that a larger drill would have made enough difference to keep me going. In fact, if you are going to do it right I would buy a dedicated jackhammer.
A friend of mine cast concrete gate posts using sonotubes. He cleared away all the rubble down to solid rock and drilled into the rock. Somehow he fixed the rebar into the rock either with epoxy or cement. Either way, if you are building on top of a sizeable piece of rock and if you have truly fixed the rebar into said bedrock, then you just achieved the largest possible footing for your post. Why dig out solid rock only to replace it with solid concrete? The answer would be it there was no rebar in the rock. If however you find a good way to set the rebar in the rock then you get around that and can take advantage of what would otherwise be an obstacle.
A friend of mine cast concrete gate posts using sonotubes. He cleared away all the rubble down to solid rock and drilled into the rock. Somehow he fixed the rebar into the rock either with epoxy or cement. Either way, if you are building on top of a sizeable piece of rock and if you have truly fixed the rebar into said bedrock, then you just achieved the largest possible footing for your post. Why dig out solid rock only to replace it with solid concrete? The answer would be it there was no rebar in the rock. If however you find a good way to set the rebar in the rock then you get around that and can take advantage of what would otherwise be an obstacle.