Open letter to Bunbury shire council on 14/9/2025.
This document links to a number of other documents, which are all available from https://gigswa.com/wall/shire/
My uphill neighbour added new retaining walls to their front lawn, and raised the ground level 700mm at the boundary fence / boundary retaining wall with no other support.
The boundary fence broke and at the same place the 1.7 meter high retaining wall beneath it cracked and bulged.
Neither the boundary fence nor the retaining wall were designed to restrain this 700mm of extra sand.
Council regulations require all retaining walls should not have additional loading placed on them above what they were designed for, regardless of who's land the retaining wall is built on.
Structural engineer's reports stated that the extra over burden could cause the boundary retaining wall to collapse, however the Marshes refused to remove this overburden because of fears that it would undermine their new retaining walls, which have their foundations approx 700mm higher than the top of the original boundary retaining wall, and 550mm higher than an abutting retaining wall on our common neighbour at 14 Keble Heights.
Structerre were originally asked to come up with a solution to this problem, but not only failed to do so also failed to notify anybody that it was too difficult for them. I did not find out until much later that Structerre were the cause of this problem in the first place.
This letter is to get the Bunbury council to get a new engineering report, signed by an independent engineer, on this issue.
Basic principles for any building
All engineered retaining walls and most retaining walls under 1 meter, (which do not need a building permit) slope inwards towards the high side, so if for any reason the wall rotates there is a safety margin before it will fall over. Once the top of a retaining wall rotates to the point it has no downward support it will fall over.
All boundary retaining walls built must legally be within the height of a retaining wall brick, otherwise an extra layer of bricks must be used.
All retaining walls need a drain of some sort to prevent water build up behind the retaining wall.
If for some reason the retaining wall has to much overburden, and starts rotating outwards, it will leave a cavity between the backing blocks and the wall itself, the size of that cavity depending on the amount of rotation.
A retaining wall holds all the weight of the ground against it, and less and less weight as the ground gets father and father away from the retaining wall. As a rule of thumb, heavy equipment cannot be driven closer to the edge of a retaining wall than the height of the retaining wall, giving a 45 degree angle for any load on the retaining wall. All high risk licence holders know this, as well as most other people.
If the ground around the area in question is mostly sand, it will naturally start collapsing at about 30 degrees and will require twice the horizontal distance of the vertical drop.
Ie; with sand and a 1 meter high boundary retaining wall, the ground must be kept level above it for at least 2 meters.
Putting a second retaining wall within this distance requires the lower retaining wall to be engineered to accept the weight of both walls.
If the combined height of any retaining wall is greater than 1 meter it will need a building permit.
Engineers must be registered to undertake design, construction or production work in prescribed areas of engineering for a building or incidental structure under the Building Act 2011 and the National Construction Code.
Any engineer signing any paper is putting that registration at risk if it can be shown that it is wrong.
Any Engineering report without an Engineers signature is not an engineering report, but instead is a good indication that a registered Engineer has refused to sign off on it for good reason.
Getting a person / company to report on an issue that was caused by themselves is a extreme conflict of interest.
When the properties in question were subdivided, it was common practice to have the contour drawings relative to a local point.
When sewerage lines are run it is important to have the right angle for flow, too steep and the solids get left behind, too shallow and it does not flow. For this reason sewerage drawings are relative to the Australian Height Datum, (AHD), as are all modern contour drawings.
Sewerage system
The people installing the sewerage system pipes and manholes have only a vague idea of where the ground level will finish up.
The owners of the land are subdividing and also have only a vague idea of what the land buyers will do.
If the manhole covers are set too low, there is a very real danger the manhole cover will be buried and hard to find in 10 or 20 years time.
If the manhole covers are set too high, there is only minor inconvenience to the land owner, who will see it there before they buy the land.
Therefore, on the side of a hill, sewerage manholes are more likely than not to be above the original ground level as they are set in concrete, and any plastic pipe is likely to be well above the original ground level as it is very easy to change once the new ground level has been determined.
Bunbury shire
Report from Shire of Bunbury.
Mentioned in court, David Brightwell from the city of Bunbury sent the Marshes an email stating that he had visited site and found no evidence of a raised ground level.
So David Brightwell visited site, saw retaining walls stacked on top of each other between 14 Trinity rise and 12 Trinity rise, saw the contour drawing showing the ground level at the manhole on the 36 meter contour ,saw the Sewer map showing the top of the manhole at 36.94 M, saw the ground level raised to the height of the sewerage manhole, saw a 700mm difference in the hight from the top of the boundary retaining wall(s) to the new ground level, saw that same boundary retaining wall extend over two extra uphill properties, where the ground level was level with the top of the other sections of the same retaining wall, and over two different downhill properties on the same retaining wall on the downhill side, and found no evidence ? I would suggest that this is not complete incompetence but blatant corruption.
In that same email David also stated that there were no other previous records for retaining wall building permits for 11b Kebel heights, after looking at Building Approval 11489 issued on 7/7/1994, for the boundary retaining wall in question and Building permit (11335) given for an additional retaining wall at 11b Keble heights, College Grove. (West)
By itself this is pure incompetence, in combination with everything else it is hard to imagine this is anything but corruption.
Gary Bruhn from the city of Bunbury signed off on a document stating, amongst other things, that the new retaining walls on 14 Trinity rise were unlikely to affect other properties.
Either he did this without visiting the site, he is totally incompetent, corrupt or a combination of all three.
Building permit issued for new retaining walls at 14 Trinity Rise to be built parallel to their lower boundary fence. Design, Permit, requirements,
compliance.,
Marsh contour drawing I was denied access to before the magistrates court hearing.
All the above was done without getting an independent structural engineer to look at it, and instead consulted the same people that caused the problem (Structerre). Structerre Report concerning soil at foot of new retaining wall.
This was requested to determine how much overburden on the original boundary retaining wall could be removed, but the report does not cover this scope, and was signed off by an assistant, not an licensed engineer, implying that an engineer knew full well that it was wrong, but did not want to risk his licence.
I was not aware of this until revealed in court paperwork in 2015
Requested building permits
I requested building permits for the disputed boundary retaining wall and I was told they did not exist.
It was only after I paid for a full set of drawings that I discovered that not only did they exist, but there were two retaining wall building permits, including one for a different retaining wall.
It also came to light that not only did they lie to me, David Brightwell from the city of Bunbury send the Marshes an email stating that 11b Keble Heights has no building permits for the original retaining walls.
As well as being wrong in fact it also breached confidentiality laws. I did not discover this for a long time.
This also reeks of corruption.
Persistent danger
With the retaining wall stacking issue between 12 & 14 Trinity rise, there is a danger that this illegal retaining wall will collapse, with anything and anyone near it being damaged / destroyed or killed.
Signing off on building permits
Signing off on building permits that "it did not affect other properties", when it fact it caused well over $30,000 damage also reeks of corruption.
New Civil engineers report scope
I am willing to guarantee a new independent, ie not Structerre or anyone associated with Structerre, Civil engineer report, signed by an actual Civil Engineer will find problems with the ground level and retaining walls at 14 Trinity rise, College Grove, on the condition that I, Andrew Laughton, also get a copy of this report.
The scope of any civil engineers report should include;
The legality of the stacked retaining walls between 12 & 14 Trinity rise.
Relevance to the building act 2011, section 77, Raising the ground level not affecting other properties.
Comment on the relationship between the top of the sewerage manhole to the current ground level.
Comment on the relationship between the top of the sewerage manhole and where the contour drawing shows the ground level should be.
Comment on the building permit form BA3 point 10
A Balustrade shall be provided if any level is more than 1 meter above the surface level below, with a {balustrade} minimum height above finished floor level (FFL) of 1 meter or 865mm above the nosing line on stair.
The building permit plan showing 7 steps 190mm high = 1.33 meter drop to both levels.
The Uniform Building By-laws 1974, section 33.4 states in part that “Where two footings of a building abut or touch one another, the underside of the footings shall be placed at the same level”.
A Retaining wall on 15 Keble heights abuts the new retaining wall at 14 Trinity rise, however there is a difference in height between the underside of the footings of about 550mm.
This guarantee is limited to 6 months from 14/9/2025, and $1,000, which should be more than adequate for this report, and on the condition that Andrew Laughton gets a copy of this report.
