Fence post in solid bedrock on a slope.

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Old 07-13-13, 11:04 AM
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Fence post in solid bedrock on a slope.

I want to put a wooden fence post around my property. The problem I have is that the back half of my backyard is all bedrock and sloped about 30 degrees, maybe more. I want to be able to use wooden fence posts. I have been researching post anchors but none of them say how to deal with a sloped bedrock surface. How would I get the anchor level, and would I need to use anchoring grout underneath the anchor since it will not all be touching bedrock. I was thinking about putting an anchor in with anchor wedge bolt and using setting screws to get it level and then packing anchoring grout underneath it. But what type of fence post anchor would I need. The fence will be 6 feet high. Any body have any suggestions on what post anchors to use? or any suggestions on how I would do this?

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Old 07-13-13, 01:43 PM
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I have no experience with this situation so I'm just throwing out ideas.

I'd consider boring into the rock and inserting a pin. I don't think it needs to be anything fancy. Maybe even a piece of rebar just dropped in the hole. Then bore a hole in the bottom of your fence posts and slide them down over the pin. For added security you can grout or glue the pin into the rock but I imagine the weight of the fence would hold everything in place. But, drilling the hole vertically is the key but if you are off you could just beat the pin with a mallet until the part above ground is vertical.
 
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Old 07-13-13, 02:43 PM
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There is going to be an awful lot of force on the base attachment of a fence held with only one anchor-holding a bracket-holding a 4x4. Your anchors need to have some sort of flange on the bottom to spread the load out and provide multiple attachment points. It also will be fairly flimsy in terms of lateral strength if you build it in a straight line. If you build it in a zig zag fashion where every panel is offset somewhat to the next panel it might work. If you have ever installed handrails using the anchors you are talking about you would understand. The railing is terribly wobbly until you get to a corner and attach a run from another direction. Then it becomes rock solid (no pun intended).

The problem with the post brackets is they do not extend far enough up the sides of the 4x4 to control sway, and a single attachment point will not protect from sway either.
 
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Old 06-29-14, 09:11 AM
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I got around to building my fence a few weeks ago. I had 1/4 inch galvanized steel brackets made up with a 1" diameter, 1 foot long rod on the bottom. I drilled a 1 inch diameter hole into the rock and hammered these brackets into the hole and attached my 4X4 posts with lag bolts. I figured I would need something else to stabilize the fence. I drilled some holes 3 or 4 feet back from the fence into the rock and attached a plate with an anchor bolt and put a brace on the fence. The fence is solid. I was surprised how strong and sturdy it turned out. Here is a picture showing the fence. You can't see the braces on the back side of the fence. I think it turned out great.
 
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Old 06-29-14, 03:34 PM
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Nice job and thanks for the feedback. The braces will help with the strength of the fence. Lets see how it holds up over time. That is the true test. Cheers.
 
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Old 06-29-14, 05:38 PM
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Holy Crap! Thats in your back yard? I think you should open a skate park.
 
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Old 06-07-16, 01:23 PM
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Post My back yard is on bed rock

I have similar situation in my back yard. I tried to make hole using hammer drill but I could not go more than 1/2 inch down in rock. I must be doing something wrong. Also do I have to use concrete with the wood bracket at the bottom because it will elevate the fence clearance from the ground. My house is on top of the mountain so too much wind which I must consider.
 
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Old 06-07-16, 03:37 PM
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Nice fence job. I noticed that you are in Canada. Is the fence intended to keep out moose, wolves, bears or Trump?
 
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Old 06-08-16, 10:45 AM
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The fence is intended to keep out all of the above! LoL!
 
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Old 06-08-16, 03:13 PM
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Most likely you will need a bigger hammer drill. 3/4 or bigger.
 
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