I omitted the two horizontal rebars that I had planned to drill and epoxy into the main patio slab because the ridges made by the hammer drill will provide a mechanical bond between the new footer and existing patio slab. We set ours in dirt/gravel and realized it was exactly the right choice when our fence was hit by a car 4 months after we built it. The car shattered two 4×4 posts, a gate, and several rails, a 3rd posts was pulled from the ground, and every other post along the run titled about 5 degrees including a 6×6 corner post; 10 posts had to be reset in all.
Often the wood post is rotten or deteriorated so there is nothing remaining above ground that is sturdy, the concrete footing is of unknown size and depth, and the fence to be repaired is in a location close to buildings or utilities that restrict access of heavy equipment (not even considering the rental expense or the damage they may cause to lawns).
The reason you don’t see any concrete at neighboring homes is most contractors will allow for a small amount of sod to sit right up against the post so you don’t see the concrete, this looks nice but can lead to your wood rotting, the steel post ties are garbage most of the time they bend and hit a rock or something on the way down an shift a weird way strongly don’t recommend them.
Applying a brute force method of lifting concrete is simply a bad idea; concrete is extremely strong when compressed, but extremely weak when pulled – in fact, the tensile strength of concrete is only about 10% of its compressive strength ( Properties of concrete reference ). Pulling the concrete out of the ground is likely to cause dangerous flying chips as the concrete fractures under the tension.
I’ve heard of the same thing, but have never tried it. It probably depends upon how wet the ground is. Right now it my back yard a post hole would fill with water as fast as you can dig it. I know that concrete will set up in the bags after a while if they are stored in a damp location for very long, so I would guess the ground dampness would make it set up as well.
To prevent this, we use our tried and true method of setting fence posts that goes far beyond just digging a hole and throwing some concrete in before inserting the post. But I’d have to figure out a way of securing the jack to the post first, maybe using some kind of lag bolt with a hook or eye on it. I forgot to mention this:put a few shovels full of soil in the hole first before poring the concrete so the concrete can’t ooze under the post. You will find a solid concrete top, but as you pull it out of the ground, the lower portion is probably going to be drier and brittle. Cut a piece of 1-by-4-inch or 2-by-4-inch lumber to twice the length of the fence post diameter.
It will also help the do it yourselfer set a solid footer that will keep their new fence in a nice straight line for years to come! TIP – Start the pry bars at 45-degrees or less – if they are too vertical the bars will be pushing against each other and not push the concrete plug UP. Hole depth should be 1/3 the overall post length, plus 6 inches (150mm) for the gravel base.
With the water turned on fully to the spike, apply even downward pressure to both pry bars requires 2 people, lifting the concrete footing and fence post. Put 6inches of gravel in the bottom of the hole and tamp the gravel firmly every 2-3inches as you fill the hole and plumb the post. Snap the top rail into one post, slip it over the picket tops and snap it into the other post. There is a new product on the market called The Post Collar that solves that problem.
The real problem that I’ve run into revolves around the fact that wind stresses build up at the point where the wood exits the concrete. If the Ice & Water shield is above the concrete your post should last…. well I dont know 100% but I will bet it will last 50+ years. Shovel or pour concrete into the hole until it reaches the top of the flared section.
If the pier shown just above was made using steel re-bar reinforcement I don’t think we face an imminent collapse of the structure above but if not, that’s possible. You’ll be able to straighten posts that get a little out of line just by pushing them around up to a couple of hours after the concrete is added. Put gravel in each hole so the bottom inch or two of the post is set in gravel.
The change in the way I do my fences was actually taught to me by Norm from This Old House and I would never use concrete again unless the soil required it. Not sure which is best either, but I will say in hindsight there is a section of my deck where I wish I had set 8′ 4x4s for the railings. I have put many fences up on my properties over the years; when I was just learning, I put fences up with concrete and have since had to do repairs and even replace them. If the masonry bit becomes clogged with concrete dust, rinse it in the can of water.
However, warmer outside temperatures (summer) means a faster set time, colder temperatures (winter) means a slower set time. Then dig and set the end posts (Photo 1). (Read the next section for details on setting posts.) Use the rail holes on the posts to determine how deep the holes should be. (Read your fence instructions. Now that you have removed the concrete plugs and have a nice clean hole, don’t repeat the mistake by setting your post with concrete. For more information on selecting and prepping your fence posts, see the method above.
The top half of the Simpson is above ground and holes for bolts and nuts to go through to hold the post in place. So if you want it to be portable or something, you will eventually just have to grab it by the stake or the concrete to move it around. Use a gravel bed for the footer, it allows drainage and doesn’t retain water that can wick up the endgrain of the post. The author covered both concrete and compact dirt/rock footers for wooden fences. I saw some homeowners building some pergola/fence and they used gravel in the holes instead of concrete. I live in NH just as you do, so digging a hole 3′ deep and trying to remove concrete is terrible.
I would place the post in the hole, back fill it with a small amount of soil or stone, tamp the post level and then back fill the rest of the hole with cement. Roughly measure the steepest slope that your fence must span (measure the rise for each horizontal foot) and ask your fence supplier for advice. The earth itself can serve as the form for concrete, or you can set the post in a large cardboard tube. I am concerned about the metal brackets having enough support on the axis perpendicular to the fence line.
The post can be set in a hole that is partially filled with concrete, then topped off with soil or gravel or, for even greater stability, the hole can be filled to the top with concrete. Once you’re down to the dirt, use post hole diggers and go another foot or so into the dirt. Allowing concrete into any rail could eventually cause that rail to sag from the weight.
As I said before, this eccentric load is also actively working to overturn the cantivlevered posts and results in much larger moment and shear values than most simple post and beam structures. In your case, the posts are already set, so adding concrete won’t make the drainage any better or worse. Pour up to one gallon of water into the hole until is soaks into the QUIKRETE Fast Setting Concrete Mix and allow the concrete to set for 20 to 40 minutes. Post bases do not provide adequate resistance to prevent members from rotating about the base and therefore are not recommended for non top-supported installations (such as fences or unbraced carports).
If we’d had concrete I suspect more would have broken, and we would have been unable easily reset any that had titled (granted fewer might have tilted but that energy had to go somewhere, hence the assumption about more broken posts). Keep in mind that you will need to remove the bottom of the sleeve or moisture/ water will trapped in a fence post application. During installation of your new fence you will find it easier to start at the top of any slope and work down hill.
Setting them in concrete was the standard way, I thought…. As you also mention, build up the concrete at the top and add a downward-cone taper so that water runs off and away from the wood. Concrete gravel boards that are used with morticed posts for closeboard fencing are attached using metal two pin push-in cleats. YES you must brace the end posts-this is a tension fence-same kind of idea if you did a wire, or wire mesh tension fence (which I would assume every fence installer is familar with??).
Ironically many concrete manufactures recommend poor installation methods, and common old school methods die-hard. A hole filled with concrete keeps the post straight, and a narrow trench from the house carries the wiring – you could do that all in a day, as This Old House technical editor Mark Powers shows here. In order to increase the life expectancy of the post, it is recommended to use post anchors that are above ground, such as a galvanized metal post support. Set the post in the hole, check the sides with a level and adjust the post until it is plumb.