fence post in concrete drieway/walkway

[mook Johnson]

I need to set two 4"x4" in aluminum fence post through the concrete in my driveway/walkway. This is for an aluminum ornamental fence between my house and deteched garage across the breezeway.

I figure I could rent a core driller from Lowes to drill two 6" holes in the concrete (~4" thick) But I have to dig the post hole to a total depth of

24." I cant get a post hold digger through a 6" hole. I wonder if the cure driller can be lowered to make a 24" deep core? The soil under the concrete is hard gummy grey clay (Houston Tx).

I know I could rent a small augger but I'm trying to save some money and find a cheaper way. I have a post hole digger for the other 3 holes (5 total) so it won't be too bad once the get is installed.

So, any ideas for digging out soil under a 6" diameter hole in concrete? Besides a teaspoon. :)

thanks

[thuddy]

How about anchoring the post to the concrete instead of going through it???

[hrhofmann]

Are the aluminum posts hollow? Probably!

If they are, you could drill a smaller 1" or 2" hole thru the concrete and then use a sledge hammer to drive a 1" or 2" steel/iron pipe into the ground and then put the aluminum posts over the steel pipes. You could put wood inside the aluminum to pad the spaces between the two posts or allow them to touch directly. The dissimilar metals should not be a problem for many years.

Bob Hofmann

[Joe]

How about jamming a 5" diameter piece of vent pipe (two feet long) down the hole in the concrete, and sticking a garden hose down to the bottom while you chop at the clay with a prybar or similar and washing the debris out of the hole. It ought to be real quick, but maybe a bit messy. They do oil wells that way, don't they?

Joe

[Jim]

I think maybe I would just dig out as much as possible with a little garden hand shovel and then drive the pipe straight into the ground with a sledge hammer. Or if you prefer tap with hammer then pull up and clean out the pipe, then hit the hole again, keep doing this cycle until your deep enough. Then cement the top of the hole.

Or you could also use a round end post (for chainlink) and use it to plug drill the hole, just keep moving it around until the hole is big enough to suit you.

Cheers, Jim

[mm]

This is where I came in. We had a long discussion about this within the last 2 months. That was for a guy who wanted the fence to be temporary, and still I think it was concluded that it woudln't work. IIUC, the OP doesn't need that.

[Jim Redelfs]

Take your posts and specifications to a local fence company and have them convert them to "plated posts". These will then bolt to the concrete eliminating the need to cut the concrete or make large holes. I have a VERY large patio fully fenced-in with chain link fabric attached to a dozen or so plated posts. Of course, you will need a good hammer drill and masonry anchors.

[DanG]

I've had good luck doing this. Get some scrap pipe - 2" EMT electrical conduit works well. Drive into the dirt and pull out a plug. Repeat until complete. You can even bell the hole. If you have plenty of pipe, just keep using it up. You could use some type of rod to clear the pipe.

[mook johnson]

WOW, A lot of excellent ideas and things I haven't thought of.

I think I try the plug drill technique first. The clay should help with that as I recall it sticking to my shovel when I dug at flower bed. If thats going too slow, I'll try the oil drillers technique. I'm in the oil drilling business, why didn't I think of that.

I also like the idea of expansion joints around the posts. I'm in Houston and summers get scortching hot. but winters are mild with the occasional freeze during a cold front.

I'll talk with the fence company about the corrosion of aluminum against fresh quickcrete. They claim their powder coating is tough as they come and offer a lifetime guarantee on the finish. I'll have to see if it covers the part that stick into the ground. Theis instructions don't call for

thanks for all the input.

This is an awsome group.

[SteveB]

If you do anything below the surface of the concrete, you're betting it's going to be good for life, or at least until the next buyer. Any breakage or corroding off of the posts, and you have no way to replace it. Aluminum corrodes terribly. I'd surface mount them.

Steve

[Ernie Willson]

If you did this you could fill the aluminum tubes with cement. This should make a strong assembly.

EJ in NJ

[Oren]

In my area some fences/patio covers are made with Aluminum, a product called alumawood . Looks like wood, with visible grains ...

Any post anchored on the pad is on the surface mount. One built in '95 still stands is not corroded.

[mook johnson]

I just got a email from Jerith and they suggested not putting expansion joints but instead using hydraulic cement or grout around the poles to take up the slab expansion. They didnt like expansion joints because they will get loose over time and pull the gate out of alignment.

They also said that their powder coating is protection from the corrosive affects of cement.