How to fix a bent plinths of a fence?

[NikkyVege]

“Looking for suggestions on how to fix the plinths at the base of my fence. What tools would I need, and what can be done from the inside of the yard to prevent the soil from sliding? Any helpful video recommendations are also welcome. Thanks!”what can be done here so the soil doesn't slide

[JacobZ]

Hi @NikkyVege,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

I am assuming the blue side of the fence is the inside of your garden and the outside with the footpath is council land? Is that correct?

It looks like the main reason the plinths are bowing is that there is only one stake installed at the centre of the span between the posts to hold them in place. Plinths are pretty flexible, so for them to retain soil, they need to be supported at much closer intervals than this.

To fix it, I would start by excavating some soil from your side of the fence to relieve the pressure on the back of the plinth. Once the pressure is relieved, you can remove the old stakes, straighten out the plinths and then drive some additional supports in. Assuming your fence posts are spaced at the standard 2.4m apart, I would want to add supports every 600mm, meaning there would be three between each set of posts.

You could use something like these 400mm Galvanised Steel Plinth Pegs, some star pickets or hardwood stakes. If you used star pickets or hardwood stakes, you would want to screw the plinth to them with some galvanised timber screws.

If the plinths are too far gone, you might consider replacing them with timber sleepers, which would be much better at holding back the soil long term.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob

[NikkyVege]

Hi Jacobz,
Thanks for getting back to me. You’re right — the blue side of the fence is the inside of my garden, and the outside with the footpath is council land. The fence posts are the standard 2.4 m apart.

Do you have any suggestions on which type of timber sleepers would be best for long-term soil retention? And would you recommend using cement sheets on my side of the fence to help reduce soil pressure on the plinths?

[JacobZ]

Hi @NikkyVege,

Really, any timber sleeper would work, as at one sleeper high, you are not retaining all that much soil. These 200 x 50mm 2.4m Treated Pine Sleepers would be fine. The main thing is ensuring they are well anchored. Again, you could use things like ultraposts or hardwood stakes, or sleeper pegs and stakes to anchor them in place.

Cement sheets aren't going to do much to reduce the pressure on your plinths as they are thin and flexible. Giving your plinths adequate support in the form of pegs, posts, or stakes is going to do a whole lot more and would be a much better place to focus your efforts.

Let me know if you have any further questions.

Jacob

[NikkyVege]

Hi JacobZ,
"Noticed that the sleeper lengths between posts seem a bit different from one post to another. I need to replace about 5 sleepers — what’s the best way to get the right sizes or match them properly?"

[EricL]

Hello @NikkyVege 

If the posts are spaced wider than 2.4 meters, it is possible to purchase longer sleepers such as the 200 x 50mm Sleeper H4 Sienna MicroPro 3.0m. Please note that any cut section must be re-sealed with TWA Woodcare 300g Ecoseal Tanalised Timber Treatment - Bunnings Australia. Please make sure to wear personal protection such as gloves, goggles and a mask when using the spray.

If you need further assistance, please let us know.

Eric

[NikkyVege]

"Hi @EricL,
Thanks for the suggestions earlier. After removing the soil from both the inside and outside, I placed the new sleeper and added some extra wooden pegs for more strength. I do have a couple of questions,though — should I be screwing the sleepers in now or just leave them as they are for the moment? Also, what can I add on the inner side to prevent the installed sleeper from bending?
I’ve attached a few images below for reference." 

[EricL]

Hello @NikkyVege 

If you can screw the sleepers to the post this would be the best time to do it before the soil leans back on the sleeper. Your idea of providing extra support using wooden pegs is a good way to keep the sleeper straight. I suggest adding more every half meter along the length of the sleeper to prevent it from bowing. I recommend screwing the support to the sleeper to prevent it from moving.   

If you need further assistance, please let us know.

Eric