Fixing a fence?

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jc100

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Previous house owner didn't put fence posts in concrete. So with the recent drought conditions and now the heavy rain my wooden fence is sagging outwards in one corner. This is a 6ft fence with 4x4 posts and boards.


Whats the best way to fix this? Dig around the loose post, prop up and backfill with concrete? Looks to only be two posts that are the problem right now but the weight of the fence might pull others loose.
 
Do you plan on staying there? If so, I'd figure out how deep those posts are first. If they're not sufficiently deep, you might be wasting your time after a winter. If you want to say there, I'd consider doing a complete rebuild..it's not that expensive or hard to do if you're already doing what you're about to do.
 
Build new posts then remove old posts. If not, as mentioned, rebuild
 
Yes staying there. This is the third summer in the house with no problems before but this summer has been weird for weather. It's a long fence, I don't really want to do a complete rebuild though. The posts aren't rotten below ground, the earth has shifted, I took a look before. I'm just wondering if setting them upright with props, digging out the base and shoving a bag or two of quickrete in will fix it for now?
 
jc100 said:
Yes staying there. This is the third summer in the house with no problems before but this summer has been weird for weather. It's a long fence, I don't really want to do a complete rebuild though. The posts aren't rotten below ground, the earth has shifted, I took a look before. I'm just wondering if setting them upright with props, digging out the base and shoving a bag or two of quickrete in will fix it for now?
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If its deep enough it might work.

But if you're gonna do that you might as well do it once and do it right. Get some concrete in that mofo and you're set
 
invictus43 said:
Do you plan on staying there? If so, I'd figure out how deep those posts are first. If they're not sufficiently deep, you might be wasting your time after a winter. If you want to say there, I'd consider doing a complete rebuild..it's not that expensive or hard to do if you're already doing what you're about to do.
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Missed that the first time round. You're absolutely right about checking the depth of the posts. I'll dig a test hole tomorrow to see. I ****ing hate digging post holes.
 
Do you know what the subsoil is like?

I'm digging a two foot deep hole to plant a tree and had to use a jackhammer to break the dried clay in one spot. Several years ago I put in some fence posts and using a hand auger it took hours per hole because the clay was so hard.

I had the rest of the holes done by a fence company and they used a power auger, much faster. They set the posts in concrete but the hole was flared at the top so when the frost heaves the ground it pushes up on the flared concrete and lifts the posts. If you mess around with just digging near the surface you could end up with the same.

If you can drive a piece of pipe into the ground near the fence you can hopefully extract the core and be an amateur geotechie. You will have some idea of what to expect.

My first thought would be to try and pour some thin slurry in along the posts.

If you can wiggle the posts it might give you an idea of the depth. My gut feeling is that the posts aren't set that deep.
 
Yes they wiggle. Past few weeks the earth has been baked dry with big cracks in it...recent heavy rain seeped into the cracks and I think it's loosened and disturbed the post foundations. By the looks of it and the ease with which I can wiggle these two problem posts (thought it was one, another is slightly loose) I don't think these two are set much more than 12 inches down, either that or they are rotted well below the surface. The earth is an easily moveable loose mud right now where these two posts are, the rest of the land is clay I think. Good news is that I can prop them up to vertical pretty easily, the plan today is to get as much earth as I can from around them on both sides of the fence and hopefully between and under the opposite sides and replace that with quickrete poured right in. The moisture in the soil right now should set it up nicely. I might have to spend a bit of time over the next few months digging each post out the same way and doing the same thing to each one in turn to make sure the frost heave in the winter doesn't do the same thing.
 
jc100 said:
Yes they wiggle. Past few weeks the earth has been baked dry with big cracks in it...recent heavy rain seeped into the cracks and I think it's loosened and disturbed the post foundations. By the looks of it and the ease with which I can wiggle these two problem posts (thought it was one, another is slightly loose) I don't think these two are set much more than 12 inches down, either that or they are rotted well below the surface. The earth is an easily moveable loose mud right now where these two posts are, the rest of the land is clay I think. Good news is that I can prop them up to vertical pretty easily, the plan today is to get as much earth as I can from around them on both sides of the fence and hopefully between and under the opposite sides and replace that with quickrete poured right in. The moisture in the soil right now should set it up nicely. I might have to spend a bit of time over the next few months digging each post out the same way and doing the same thing to each one in turn to make sure the frost heave in the winter doesn't do the same thing.
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The rotting off just below the suface could be the problem. I had it happen to an old cedar 4 x 4 fence post. I was able to carefully pull out the old post and drop in a new one without digging. It took a lot of extended speedbores.
How difficult would it be to remove the fence boards to access the posts?
 
Do not put concrete around them this will guarantee a fence that need torn down and fixed after a winter. Post can be done 2 ways properly, 1 is to dig the holes put concrete in the bottom of the hole only and then fill around the posts, pouring concrete around the post gives the frost a spot to grab onto and heave the posts. The second way is to uses sona tubes around the posts and fill them with concrete, the smooth surface of the tube keeps them from heaving.
 
Scuba Steve said:
Do not put concrete around them this will guarantee a fence that need torn down and fixed after a winter. Post can be done 2 ways properly, 1 is to dig the holes put concrete in the bottom of the hole only and then fill around the posts, pouring concrete around the post gives the frost a spot to grab onto and heave the posts. The second way is to uses sona tubes around the posts and fill them with concrete, the smooth surface of the tube keeps them from heaving.
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This sounds like the voice of experience. Any tips on a new installation? Minimum depth etc? I may have to help someone in Hamilton.
 
How much room is around the fence? You might be able to support the fence by using 2x4's and bracing it and remove the 4x4's and dig a deep hole or get a auger and reset the 4x4's.....



basically what this guy is doing....sepratethe fence and reinstall he 4x4 into a ground below the frost line.

http://www.youtube.com/watch?v=Ja1idbbKo58[video=youtube;Ja1idbbKo58]http://www.youtube.com/watch?v=Ja1idbbKo58[/video]
 
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jc100 said:
Yes staying there. This is the third summer in the house with no problems before but this summer has been weird for weather. It's a long fence, I don't really want to do a complete rebuild though. The posts aren't rotten below ground, the earth has shifted, I took a look before. I'm just wondering if setting them upright with props, digging out the base and shoving a bag or two of quickrete in will fix it for now?
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Like Scuba Steve said, that'll work for a year. You want to make it a yearly chore?
 
Nah...you're all correct. It ****** down with rain the other day so all I could do was prop them up anyway. I'll separate the fence at the posts individually and sonotube the ****ers in when I can. The props will hold until the soil stabilizes. Anyone seen the new stuff used for setting posts? It's not concrete, some new fangled thing. I'll try to get a link.
 
It's fence post setting foam.....utility companies use it apparently. Still trying to get a good link. Anyone used this?
 
Hi John, I haven't used the new stuff, just saw it at Lowes this past weekend. I don't know how well it works, but like anything, if you don't get it deep enough, the frost will just grab it and lift it. If the posts are only a few inches (a foot or so) deep, it dosen't matter how well you set it, it will fail. If it is shallow, and you don't want to replace them with longer posts, get some t-rail posts and drive them into the ground right beside your wood posts and then bolt the wooden post to the t-rails. That should give the lateral strength so they won't tilt, but they may still lift. L
 
Lyndsay said:
Hi John, I haven't used the new stuff, just saw it at Lowes this past weekend. I don't know how well it works, but like anything, if you don't get it deep enough, the frost will just grab it and lift it. If the posts are only a few inches (a foot or so) deep, it dosen't matter how well you set it, it will fail. If it is shallow, and you don't want to replace them with longer posts, get some t-rail posts and drive them into the ground right beside your wood posts and then bolt the wooden post to the t-rails. That should give the lateral strength so they won't tilt, but they may still lift. L
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Hey Lindsey...how's the summer going? I have a new toy to show you.

Anyway..the fence is in Ottawa...going to have to dig a bit deeper to get below that frost line. The foam looks interesting as I can pack more of it in the truck and lifting it isn't as bad for my back as a few dozen bags of concrete. My only problem is wondering how it works without the mass?
 
I don't know specifics about the foam but have worked with 2 part stuff for boat floatation. I would trust concrete first but I'm a luddite.
 
How I would fix it properly..

- Remove 1st and last fenceboard on the two panels of fence adjacent to the post that is sagging.
- Support fence panels on blocks of wood or equivalent.
- Unscrew or cut the nails (with a hack saw or sawzall) that secure the stringers (2x4 cross rails) to the post
- Remove two complete fence panels and lay them down keeping them as intact as possible. Keep track of how they are positioned in the fence
- Dig up the sagging post. If it's not rotted you can re-use it. If its rotted replace it.
- For a 4x4 post use an 8" auger or rent a clam shovel an dig a roughly 8"-10" diameter hole to a minimum depth of 3 feet. Try to keep the sides vertical, or even flared out at the bottom to prevent frost heaving. If re-using the old post make sure it's long enough. It may not have been deep enough originally and the deeper hole will make the old post too short.
- Measure the length of the two bottom stringers on the two fence panels.
- Run a string line between the two posts on either side of the post being replaced
- Using braces, set the post level and on the string line, and position so the gaps between posts match the lengths of the two bottom stringers. This is the tricky part, take your time and make sure you get it right otherwise you'll need to do some trimming/shimming to get the fence panels back in.
- Use two bags of quick-set (perhaps 3 if you have to make the hole bigger to get rocks out and such). Fill with quick-set to about 3" below grade then level it off with soil. Leave it for a few hours.
- Position the fence panels on blocks in their original position. Secure to the old and new post then remove blocks. Re-use old fence boards or put up 4 new ones.
- Cut/cap top of new post off to match the rest of the posts (if you have a new post)
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