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The guy at Bunnings had no idea, and the guy at the local garden centre was nearly as helpful, so I thought I'd try the good folk here.

I've built a retaining wall. It's really just a raised garden bed (in my opinion), but we'll stick with retaining wall for arguments sake. It's in an L-shape, 8 metres in both directions. It's 2 blocks high and comes to 400mm. The wall is about 1.5 metres away from the back and side fence. The fence is colourbond Good Neighbour style. I intend to fill the area between the wall and the fences with soil and then put in some plants.

I have some concerns regarding the soil corroding the fence and the possibility of the soil pushing against the fence and eventually causing it to lean.

So, should I worry about the pressure from the soil against the fence, or is it low enough not to be a problem? What should I put against the fence to prevent corrosion. I've looked at some thick black plastic sheeting or alternatively, treated pine sleepers slotted between some RSJ.

I did wonder about using some blueboard and some star droppers...

Any other options or advice?

colourbond fence shouldnt corode. its aluminium isnt it??

as for the rest NFI! unless you want to build a concrete wall??

I was in the fencing game for 3 years. If ya have good footings around the post, the fence will hold up(600mm deep for a 2.4m fence). Corrosion will appear if (footings) aren't built up to the post... like a pyramid. If water sits in the footings, eventually over years the post will deteriorate, even aluminium post... believe me they do.
The retaining wall sounds fine, just don't put soil against the fence as moisture and chemicals will corrode the fence.
Put up a barrier between the soil and fence. This should be fine.
Need to see some pics of what ya doing just so I have a good idea what it looks like Arrdy.
Hope this helps some.

Sounds like something similar to what we are doing.
When we get our garden sorted, we will put down some posts just off the fence and put some wooden planks down to hold the dirt away from the fence.

Thanks for the input so far guys. Glad I went out and took the photos - reminded me that one fence is post and rail.

Arrdy, between the fence and garden wall is quite high, this could over time push the fence over. Depends whats on the other side. I would build a small brick wall along the fence or put wooden planks standing on there own, not against the post, so no soil gets near it,then fill it in mate, just to be sure.

Can't help with the fence but love the avatar BTW.

JetPilot wrote:Arrdy, between the fence and garden wall is quite high, this could over time push the fence over. Depends whats on the other side. I would build a small brick wall along the fence or put wooden planks standing on there own, not against the post, so no soil gets near it,then fill it in mate, just to be sure.

yep thats what we are doing, got recommended we dont put any pressure on the fence, neighbours are assholes as they are already, so dont want to piss them off any more

JetPilot wrote:Arrdy, between the fence and garden wall is quite high, this could over time push the fence over. Depends whats on the other side. I would build a small brick wall along the fence or put wooden planks standing on there own, not against the post, so no soil gets near it,then fill it in mate, just to be sure.

It looks high, but the wall blocks are only 200 high, so just over 400 all up. I didn't really think there'd be enough soil to create pressure worth worrying about.

I don't think I want to be building a brick wall at the back. It took enough effort to build the damned retaining wall! When you say planks of wood, are you referring to sleepers joned with RSJ or did you have something else in mind?

aardvark wrote:

JetPilot wrote:Arrdy, between the fence and garden wall is quite high, this could over time push the fence over. Depends whats on the other side. I would build a small brick wall along the fence or put wooden planks standing on there own, not against the post, so no soil gets near it,then fill it in mate, just to be sure.

It looks high, but the wall blocks are only 200 high, so just over 400 all up. I didn't really think there'd be enough soil to create pressure worth worrying about.

I don't think I want to be building a brick wall at the back. It took enough effort to build the damned retaining wall! When you say planks of wood, are you referring to sleepers joned with RSJ or did you have something else in mind?

Sleepers Arrdy... If ya think its not going to be to high, lay plastic down against the fence so no moisture gets near the post and bottom rail.
Stops weeds coming through too.

Couldn't he use Formply instead of sleepers?
And screw the ply to the existing fence uprights with gal or stainless screws?

mohawk miss wrote:Couldn't he use Formply instead of sleepers?
And screw the ply to the existing fence uprights with gal or stainless screws?

I thought about that, but with blueboard. Wasn't sure about the pressure against the fence tho.

aardvark wrote:

mohawk miss wrote:Couldn't he use Formply instead of sleepers?
And screw the ply to the existing fence uprights with gal or stainless screws?

I thought about that, but with blueboard. Wasn't sure about the pressure against the fence tho.

You can use what ya like, just don't put to much pressure against the fence... in time it will collapse.

Good luck Arrdy, withh what ever ya come up with.

my sons a landscape gardener,you can have him for $50.00 posted...........but no returns or refunds

aardvark wrote: It took enough effort to build the damned retaining wall!

Mate here is a little one I did 2 years ago ... 2 hours every arvo after work + 1/2 the weekends in the summer heat & took 6 weeks to complete.
I also have a retaining wall that backs onto a colourbond fence & I used 2 layers of black building plastic between the soil & fence, the height is about 500mm
& is about 400mm deep but is only a garden bed & not for walking on ....... 2 years on & the fence has not bulged, moved or showing any signs of corrosion.
I will try to get a pic
Edit found a smaller pic of the back wall against the fence (drainage under the fence)