How to fix leaning Colorbond fence?

[dant]

Hi,

3 posts in my colorbond fence are leaning.  It was a result of somebody falling into it with force.

I made an effort over the weekend to dig down to the footers.  I only got about 500mm before I ran out of puff.  It is thick clay for the most part.  I have done this on my side and 2 of the posts on my neighbours side (although not as deep on his side as the footer starts nearer the surface due to slope down to his yard).

My thinking was that if I left enough space on my side and got below the footer I could lean some 4x2 against my neighbours side at say 45 degrees, stake the end and force it down the end against the post with a mallet thereby realigning the fence vertical.

Is this a reasonable approach?  I didn't get around to it and now I'm second-guessing myself and whether I should just pay someone with the right tools to fix it.

The water was foolishly added by me as I thought it would help when I went to try and straighten it but never got there.

[EricL]

Hello @dant 

Your proposal to install 2x4's to push the posts back into alignment sounds like a good idea. Looking at the photo you posted, it appears that the installer did not use a lot of concrete for the footing. I think this is good opportunity to reinforce the post by adding more concrete to the footing. With the extra concrete in place, it should be enough to hold the post in place. My best advice is to make sure to give the concrete enough time to cure before covering the post hole.

Let me call on our experienced members @Dave-1 and @Nailbag for their recommendations.

If you have any other questions we can help with, please let us know.

Eric

[MikeTNZ]

Hi @dant,

Thanks for posting this.

This looks like a significant amount of corrosion and rust in these members of your fence.

What I would do first off, is talk to your neighbour regarding replacing all of the vertical members that hold up this fence.

Once one of these starts to go, the rest of them will, via attrition, as they are all the same age.

@EricL mentioned 4 x 2" posts, however, for longevity of the fence, I would suggest 4 x 4" H5 posts set into concrete, with the posts set at least 2000mm into the concrete.

Use bracing both ways as the posts are set and the concrete poured, this will give you a better finish to your fence.

Don't use that cheap "pour it into the hole" concrete, mix it in a wheelbarrow.

Also, if you're keen on the fence never falling over again, drill the bottom of the posts out to take 2 x 16 mm dia rebar at right angles, 300mm up from the bottom of the post, before the holes are filled.

If you have further questions, by all means, let us know, we are only happy to help.

Cheers,

Mike T.

[dant]

Thanks @MikeTNZ 

The 4x2 idea was just to use as a lever to push it back vertical if that makes sense and then reconcrete.

[Nailbag]

Hi @dant 

It shouldn’t be possible to push over 3-4 sections of a new fence by someone falling into it no matter how hard. The photos highlight that there was never enough concrete in the post holes to start with. 

Personally I don’t believe the posts need replacing as the corrosion appears to be surface only effecting the colour layer. 

To rectify the fence posts you will need access to both sides to prop the fence plumb (vertically straight). Then dig 360deg 150-200mm out around each post hole further than the existing concrete which will be too difficult to remove. At 500mm you are very close to the 600mm the post are probably dug to. 

You will need about 3 bags of Rapid Set concrete per hole which is structurally suitable and recommended by the manufacturers for this application, just follow the instruction. Then allow 24hrs before removing the props. 

Nailbag

[Dave-1]

Evening @dant 

You have done the same steps as I would have, right down to running out of puff Going through your photos and explanations I agree that not enough concrete was used in teh first place which is why someone falling onto the fence has pushed it out of alignment.

@EricL 's suggestion to follow your lever idea and push it back to vertical and then fill the holes with more concrete is how I would approach it in the first place.

@Nailbag's thoughts on the posts being ok is where I went as well. You could paint the surface with a rust converter / then rust proof but really its going to be encased in concrete so "wiggles hands"

The only extra bit I can add is maybe use some formwork to limit the size of the hole if you have dugg out too wide. I would also do the repair sooner then later as you have dug out the support for the posts to a resonable degree. When you go to use the lever I would try and put the weight about half way up the posts and not the top, it may be tempting as it will be easier but I wouldnt want to chance the post kinking. 

Dave

[dant]

Thanks @Dave-1 and @Nailbag 

So basically, remove panels to leave 3 posts and dig around the whole post and then try to lever/straighten?

Am I best just hiring a small post hole digger with an 80-100mm auger?

Initially I thought once I hit concrete I would be able to break it up but I think it was put into maybe a 200mm hole and seems to tough to break up (with the angle).

Cheers

[Dave-1]

Afternoon @dant 

Id be lazy and try to leave as is and stand them vertical. Then fill with concrete. The holes look like you have dug out enough already to allow movement?. If it dosnt feel like the fence will be easy to stand vertical then I would remove the panels. At the moment I figure they are helping to hold the fence up.

Dave

[dant]

Thanks @Dave-1 

It just felt very firm when I was testing it out from the neighbour's side giving it a good push.  Didn't move a bit but holes aren't as deep on his side. 

Will try with the lever and see how that goes first.

[Nailbag]

Hi @dant 

Agree with @Dave-1 with boxing the holes to limit the amount of concrete. If the posts aren't budging it's going to be a matter of keep digging around. Don't bother trying to break up the concrete as that won't be required. 

Remember if you're going to remove the panels, the spacings for them once the posts are straight will be critical. Personally I would have a crack at keeping the panels in place during this process of propping and re-propping until everything is realigned.

Nailbag