Who pays for the retaining wall: me, my neighbour or 50:50?

I am building a house in an estate in QLD. One of the neighbours has asked me to split the cost of the retaining wall between us ($3,425 / 2). When I was buying the land the developer's sales person told me that the cost of the retaining wall would be my neighbour's expense. The neighbour's seller (a construction company) told him that the retaining wall would be my responsibility. I can see the pattern there now... So, what's the common rule, e.g. 50:50 cost split for the retaining wall in addition to the fence later on?
Thank you in advance.

 

Who needs the wall?

 

I've been given contradicting answers to the same questions when looking at investment properties with retaining walls at the end of their life, to the best of my understanding the person who needs the retaining wall to hold up their land pays the whole cost.

 

The answer lies here

So As a general rule, each owner is responsible for retaining the portion of earth that they (or the previous land owner) have altered from the natural ground level. This could be fill placed on top of the natural ground level or excavation below the natural ground level.

So has you'rs been excavated or the neighbors raised?

 

Where is that from @HD_ACE?
It's a lot messier than working out fences!

 

Yes. Although it may have a fence on it, They do not have the same definitions/ responsibilities of a fence.

Here's a law book stating some of the above. Albeit it is a SA one.

http://www.lawhandbook.sa.gov.au/ch31s04.php

 

Thank you, guys, for the responses.

Technically speaking, we both need it. Yes, retaining walls are much messier as they are not treated the same as fences.

I think HD_ACE is right about the changes to the ground level. I'll contact the builder to find out how the knee-high difference in height has turned into something that requires an 800mm retaining wall. Fortunately, both the neighbour and I are using the same builder.

 

If its gone from knee high to 800 they may be increasing the height. So you should only look at paying 1/2 of "knee high" (my kind of technical lingo!) , then they pay the additional height

Where is this? new development I assume. Were the blocks not level when you bought?

If you had to have your block cut and their block filled, which sounds like it's the case 50:50 is fair.

Just did a quick measure and my knee height is 600, so going up to 800 may just be rounding up to nearest sleeper or to retain grass

 

My in laws have an absolute night mare on their hands with one. It's 5m high and for their block but the neighbour at the bottom has played a part in its deterioration. Bill is up to $200k! Crazy stuff. It's moved 200mm at the top off vertical in one section.
Fear of the house falling down through Hill is a good excuse not to visit!

 

@M$ ANNA

In new estate, mostly who ever builds first and most likely it will be within in your own boundry!

(May not apply to OP)

One of the big negative of buying a land OTP...retaining wall,fencing and piering alone can cost upward of 30k on stock standard 400+ sqm block..may be forced to change design due to slope of land.

 

http://hub.planning.nsw.gov.au/Portals/0/Pdfs/prepare/Earthworks_and_retaining_walls.pdf

The info is for NSW, but it might be of some help. This information sheet provides details about earthworks and works to provide associated structural support, such as retaining walls that can be undertaken and constructed on lots across NSW as either exempt development or complying development.